CA2558003A1 - Method for producing a three-dimensionally formed armouring component for vehicle bodies - Google Patents
Method for producing a three-dimensionally formed armouring component for vehicle bodies Download PDFInfo
- Publication number
- CA2558003A1 CA2558003A1 CA002558003A CA2558003A CA2558003A1 CA 2558003 A1 CA2558003 A1 CA 2558003A1 CA 002558003 A CA002558003 A CA 002558003A CA 2558003 A CA2558003 A CA 2558003A CA 2558003 A1 CA2558003 A1 CA 2558003A1
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- Prior art keywords
- component
- armoring
- steel sheet
- producing
- vehicle bodies
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- Abandoned
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 34
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 55
- 239000010959 steel Substances 0.000 claims abstract description 55
- 238000010438 heat treatment Methods 0.000 claims abstract description 26
- 238000001816 cooling Methods 0.000 claims abstract description 24
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 7
- 239000000956 alloy Substances 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims abstract description 7
- 239000002184 metal Substances 0.000 claims abstract description 7
- 229910052751 metal Inorganic materials 0.000 claims abstract description 7
- 238000010791 quenching Methods 0.000 claims abstract description 6
- 238000009997 thermal pre-treatment Methods 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 22
- 238000003483 aging Methods 0.000 claims description 7
- 238000005275 alloying Methods 0.000 claims description 6
- 230000001419 dependent effect Effects 0.000 claims description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 4
- 230000032683 aging Effects 0.000 claims description 4
- 238000005496 tempering Methods 0.000 claims description 4
- 239000002826 coolant Substances 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 229910021529 ammonia Inorganic materials 0.000 claims description 2
- 229910001566 austenite Inorganic materials 0.000 claims description 2
- 238000005261 decarburization Methods 0.000 claims description 2
- 230000017525 heat dissipation Effects 0.000 claims description 2
- 238000003825 pressing Methods 0.000 claims description 2
- 238000007669 thermal treatment Methods 0.000 abstract description 2
- 230000006835 compression Effects 0.000 abstract 3
- 238000007906 compression Methods 0.000 abstract 3
- 238000003754 machining Methods 0.000 abstract 1
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000004880 explosion Methods 0.000 description 4
- 238000005755 formation reaction Methods 0.000 description 4
- 230000001681 protective effect Effects 0.000 description 4
- 239000003570 air Substances 0.000 description 3
- 238000000137 annealing Methods 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000011268 retreatment Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000011265 semifinished product Substances 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- 230000008646 thermal stress Effects 0.000 description 2
- 229910000919 Air-hardening tool steel Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000760 Hardened steel Inorganic materials 0.000 description 1
- 206010041662 Splinter Diseases 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000011089 mechanical engineering Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 230000000930 thermomechanical effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/42—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for armour plate
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/58—Oils
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/62—Quenching devices
- C21D1/673—Quenching devices for die quenching
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49616—Structural member making
- Y10T29/49622—Vehicular structural member making
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Physics & Mathematics (AREA)
- Heat Treatment Of Articles (AREA)
- Body Structure For Vehicles (AREA)
- Forging (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
- Fittings On The Vehicle Exterior For Carrying Loads, And Devices For Holding Or Mounting Articles (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention relates to a method for producing a three-dimensionally formed armouring component for vehicle bodies. The aim of the invention is to be able to produce armouring components in a repeatedly accurate manner with minimal post-machining requirements and with lower dimensional tolerances than comparable weldments. To this end, sheet metal moulded parts are produced from hardenable steel by means of a thermal pre-treatment, the heating speed and temperature being selected at least until the austenitic or partially austenitic state depending on the alloy content is achieved, and the formed armouring components are then press-formed and optionally subsequently subjected to quench or thermal treatment. According to the invention, the hot-forming and quench-hardening of the steel plates is carried out in one working cycle, the austenitic steel plates are formed within a maximum period of 90 seconds by means of a compression mould, the entire formed component is held in contact with the compression mould, and the formed component is cooled in the closed compression mould, with a cooling speed which corresponds at least to the material-specific critical cooling speed.
Description
Method for producing a three-dimensionally formed armoring component for vehicle bodies The invention relates to a method for producing a three-dimensionally formed armoring component for vehicle bodies by the production of sheet metal preforms from hardenable steel, with the thermal pre-treatment of these steel sheet blanks, the heating speed and heating temperature being selected until the austenitic state dependent on alloy content is reached, and with subsequent press forming and hardness treatment of the formed armoring components. Technical solutions of this kind are required, for example, in the motor vehicle construction of armored limousines.
In the production of special protective vehicles, armorings are used which are inserted into the outer planking of vehicle bodies. Since high-grade steels are difficult to process, these armorings are mostly designed as welding subassemblies. The known susceptibility to distortion and the considerable temperature sensitivity, which may bring about a decrease in strength even above a temperature of 200°C, often lead to crack formations and stress problems in the direct weld seam region and to strength problems in the heat influence zones. These undesirable effects rise with an increasing content of alloying elements and armoring hardness. This leads to an impairment of the protective effect required.
The production of three-dimensional components by hot forming with subsequent heat treatment is known.
Thus, DE 198 21 797 C1 discloses a method for the production of hardened parts from steel. This method serves particularly for obtaining preliminary products which, for example for the production of rolling bearings and transmission parts, on the one hand, are particularly resistant to fatigue, have a high load-bearing capacity and are wear-resistant and, on the other hand, are to be capable of being produced particularly adaptably in the interests of minimal mechanical remachining. For this purpose, an air-hardening steel is used, which is obtained after heating to at least 1100°C first with hot forming to a temperature of at least 800°C and then with cooling by means of air to about 280°C, at the same time with thermomechanical treatment by calibration, subsequent cooling in air to room temperature and final expansion treatment at a temperature of 150 to 250°C.
Furthermore, US 5, 454, 883 A discloses a method, with the aid of which hardened steel plates are produced in that the heating rates during thermal treatment and the holding times at selected treatment temperatures are optimized. Moreover, in a variant, this technical solution suggests dispensing with calibration during the cooling of the components.
The common shortcoming of the known technical solutions is that they are unsuitable for the production of three-dimensionally formed sheet metal preforms from hardenable steel sheets, particularly when a cutting surface retreatment of the hardened sheet metal preforms is to be avoided. To that extent, the known technical solutions for the production of semifinished products, such as are required in mechanical engineering for the production of high-strength steel structures, highly load-bearing structural machine elements in the form of rolling bearing parts and transmission parts, are unsuitable for the production of three-dimensionally formed armoring components for vehicle bodies.
The object, therefore, is to provide a technical solution, with the aid of which the shortcomings of the known prior art are overcome. In particular, a method is to be developed which is suitable for the production of armoring components for vehicle bodies, while avoiding weak points in the armored region. The armoring components are to be capable of being produced as comparable welded structures with repeating accuracy and markedly lower dimensional tolerances along with minimized remachining requirements.
The object is achieved, according to the invention, by means of the features of claims 1 and 2. Advantageous refinements are described in the subclaims.
Accordingly, the method provides for the production of a three-dimensionally formed armoring component for vehicle bodies by the production of sheet metal preforms from hardenable steel. For this purpose, the steel sheet blanks are thermally pretreated, the heating speed and heating temperature being selected such that the austenitic or partly austenitic state dependent on alloy content is reached. In the austenitized state, the predominant part of the alloying elements contained in the material of the steel sheet blank is dissolved in the austenite. During austenitization, the heat treatment time is selected as a function of the carbon content, of the quantity and type of alloying elements and of the sheet thickness, such that scaling, skin decarburization and grain growth are minimized. Thereafter, press forming takes place, with subsequent heat treatment, if necessary, as a result of which the desired three-dimensionally formed armoring components are obtained.
The method provides for carrying out the hot forming and quench hardening of the steel sheet blanks in one operation. The austenitized steel sheet blank is formed by means of a press die as immediately as possible, preferably still in the austenitic or partly austenitic state, and, as a result of the high cooling rate which is aimed at, the desired hardness structure in the formed steel sheet blank is achieved.
The required critical cooling rate is in this case selected such that a hardness structure is obtained.
In the production of special protective vehicles, armorings are used which are inserted into the outer planking of vehicle bodies. Since high-grade steels are difficult to process, these armorings are mostly designed as welding subassemblies. The known susceptibility to distortion and the considerable temperature sensitivity, which may bring about a decrease in strength even above a temperature of 200°C, often lead to crack formations and stress problems in the direct weld seam region and to strength problems in the heat influence zones. These undesirable effects rise with an increasing content of alloying elements and armoring hardness. This leads to an impairment of the protective effect required.
The production of three-dimensional components by hot forming with subsequent heat treatment is known.
Thus, DE 198 21 797 C1 discloses a method for the production of hardened parts from steel. This method serves particularly for obtaining preliminary products which, for example for the production of rolling bearings and transmission parts, on the one hand, are particularly resistant to fatigue, have a high load-bearing capacity and are wear-resistant and, on the other hand, are to be capable of being produced particularly adaptably in the interests of minimal mechanical remachining. For this purpose, an air-hardening steel is used, which is obtained after heating to at least 1100°C first with hot forming to a temperature of at least 800°C and then with cooling by means of air to about 280°C, at the same time with thermomechanical treatment by calibration, subsequent cooling in air to room temperature and final expansion treatment at a temperature of 150 to 250°C.
Furthermore, US 5, 454, 883 A discloses a method, with the aid of which hardened steel plates are produced in that the heating rates during thermal treatment and the holding times at selected treatment temperatures are optimized. Moreover, in a variant, this technical solution suggests dispensing with calibration during the cooling of the components.
The common shortcoming of the known technical solutions is that they are unsuitable for the production of three-dimensionally formed sheet metal preforms from hardenable steel sheets, particularly when a cutting surface retreatment of the hardened sheet metal preforms is to be avoided. To that extent, the known technical solutions for the production of semifinished products, such as are required in mechanical engineering for the production of high-strength steel structures, highly load-bearing structural machine elements in the form of rolling bearing parts and transmission parts, are unsuitable for the production of three-dimensionally formed armoring components for vehicle bodies.
The object, therefore, is to provide a technical solution, with the aid of which the shortcomings of the known prior art are overcome. In particular, a method is to be developed which is suitable for the production of armoring components for vehicle bodies, while avoiding weak points in the armored region. The armoring components are to be capable of being produced as comparable welded structures with repeating accuracy and markedly lower dimensional tolerances along with minimized remachining requirements.
The object is achieved, according to the invention, by means of the features of claims 1 and 2. Advantageous refinements are described in the subclaims.
Accordingly, the method provides for the production of a three-dimensionally formed armoring component for vehicle bodies by the production of sheet metal preforms from hardenable steel. For this purpose, the steel sheet blanks are thermally pretreated, the heating speed and heating temperature being selected such that the austenitic or partly austenitic state dependent on alloy content is reached. In the austenitized state, the predominant part of the alloying elements contained in the material of the steel sheet blank is dissolved in the austenite. During austenitization, the heat treatment time is selected as a function of the carbon content, of the quantity and type of alloying elements and of the sheet thickness, such that scaling, skin decarburization and grain growth are minimized. Thereafter, press forming takes place, with subsequent heat treatment, if necessary, as a result of which the desired three-dimensionally formed armoring components are obtained.
The method provides for carrying out the hot forming and quench hardening of the steel sheet blanks in one operation. The austenitized steel sheet blank is formed by means of a press die as immediately as possible, preferably still in the austenitic or partly austenitic state, and, as a result of the high cooling rate which is aimed at, the desired hardness structure in the formed steel sheet blank is achieved.
The required critical cooling rate is in this case selected such that a hardness structure is obtained.
After the closing of the press die, the formed component is held in full-area contact with the press die. The full-area contact of the formed steel sheet blank with the press die ensures the avoidance of deformations as a result of thermal stresses up to the partial or complete structural transformation of the formed steel sheet blank and serves for producing the required hardness structure in all the part regions of the armoring component generated. Weak points within the armoring component are consequently reliably avoided.
The cooling of the formed component is an integral part of the hardness treatment and therefore takes place in the closed press die.
Preferably, the forming in the press die takes place such that, during a pressing operation, with the formed steel sheet blank bearing over its full area against the impression of the press die, the rate of cooling of the austenitized or partly austenitized steel sheet blank is as far as possible above the critical cooling rate.
Alternatively to this method variant, it is possible, furthermore, that the austenitized steel sheet blank, after being inserted into the press die, is first formed and held in complete contact with the press die, the press die being cooled at least to approximately 70°C before the forming process. After the forming process, the further cooling of the formed steel sheet blank is carried out, with the press die open or outside the press die in the ambient air. In this case, it is assumed that the shock-like cooling of the austenitized formed steel sheet blank in the precooled press die leads not only to the formation of the fundamental hardness structure, but also to a sufficient dimensional stability of the three-dimensional armoring component produced. In this case, the press die can be used at a higher frequency for the production of components with repeating accuracy.
Preferably, the steel sheet blanks used are sheets of hardenable and maraging steels.
The method provides for the initial hardness of the armoring steel during hardening in hardening oil to be higher than 45 HRC or for the hardness after artificial ageing to be higher than 45 HRC.
Three-dimensionally formed armoring components with high dimensional accuracy are obtained, in particular, in that, after the forming operation, the press die is held closed for a period of time of 50 to 500 seconds until the desired cooling temperature is reached. As a result, the component is held in calibration up to the complete formation of the hardness structure, as a consequence of which deformations due to thermal stresses can be largely ruled out.
The cooling rate via the contact of the formed steel sheet blank with the press die is influenced in that the press die consists of highly thermally conductive material, for example steel, and/or can be cooled by coolants, preferably, for example, water, ammonia and/or compressed air.
It is possible to subject the cooled and formed steel sheet blanks to final heat treatment in the form of an expansion and/or tempering process, annealing or age-hardening treatment.
Alternative to this, measures, such as hardening, age hardening or artificial ageing, are also possible as thermal retreatment procedures, depending on the alloy composition. These measures serve for compensating possible uneven distributions of the degrees of hardness in the component and consequently to rule out unreliability in safety against the effects of bombardments or explosions. The thermal distortion occurring during thermal retreatment is known to be about only 10% of the armoring components produced by means of welding technology.
It is particularly advantageous that hot forming and quench hardening of the austenitized or partly austenitized steel sheet blanks are carried out in one operation.
The advantages of the invention, when combined, are that, for the special case of the production of three-dimensionally formed armoring components for vehicle bodies, specific requirements regarding the production of hardened steels, such as are known for the production of tools or semifinished products, do not have to be fulfilled. This refers, for example, to resistance to rolling fatigue, wear resistance or the fatigue limit under alternating stresses.
It may be assumed that the body of a vehicle of the special protection class is distorted completely or at least in respect of the loaded armoring components after being subjected for the first time to load by bombardment or explosion. In light of these particular requirements, the armoring components to be produced must have, in particular, continuous or full-area quality and, if possible, not require a mechanical remachining of the surface of the three-dimensionally formed armoring component. The proposed method takes these particular requirements into account to a high degree. As compared with known welded structures, three-dimensionally formed armoring components of high quality are obtained in a comparatively simple way by conjoining a hot forming process with a hardening process, starting from sheet blanks which have previously been pretreated in an austenitized or partly austenitized state.
In accordance with the desired protection class, WO 2005/078143 - '7 - PCT/DE2005/000169 characterized by defined bombardment safety and possible safety against explosions, the aim is to achieve the required heat treatment parameters.
Some annealing steels for use in protective class VR6 in this case, by the application of the proposed method, achieve, even without subsequent heat treatment, all the protective requirements, including safety against explosions by hand grenades of the type DM51, without splinter outbursts on the rear side of armoring elements.
In the design of the press dies, care must be taken to ensure that sufficient heat dissipation can be ensured at every point on the formed steel sheet blank.
Furthermore, the flow properties of the material must be borne in mind, so that, during the forming operation, the component comes to bear under uniform surface pressure completely and uniformly against the impression of the die and thinnings of the material thickness are avoided. To stabilize the component during heat treatment, beads or stabilizing forms extending continuously may be embossed in the blank.
After the hot pressing or possible heat treatment, the final form of the component is cut out by means of a laser or preferably a water jet.
By means of the proposed method, then, three-dimensionally formed armoring components for different protection classes can be produced, and their wall thickness may even amount to more than 10 mm. By hot forming, then, armoring components for vehicle bodies can be implemented, which it has hitherto been possible to produce only as complicated welding structures with ballistic weak points in the weld seam region.
Owing to the high process reliability, the large-series use of the method for the production of three-dimensionally formed armoring components with high dimensional accuracy is possible.
WO 2005/078143 - g - PCT/DE2005/000169 The invention will be explained in more detail below by means of implementation examples.
Implementation Example 1:
A steel sheet with a thickness of 6.5 mm has the following content of alloying elements:
0.5% C
1.1 - 1.3% Ni 1.0 - 1.5% Si 0.5 - 0.6% Mn 0.1 - 0.5o Mo.
From this steel sheet, a sheet blank is obtained and is heated to an austenitizing temperature in the amount of 950°C. In this state, the sheet blank is inserted into the press die and is formed as a result of the closing of the press die. Within a total of 300 seconds, the quench cooling of the formed steel sheet blank to the die temperature takes place. The die may in this case be cooled by coolant. The closing pressure of the press die is maintained over the entire cooling time.
Subsequently, heat treatment takes place by annealing to the quality HRC 50. The three-dimensionally formed armoring component corresponds to bombardment class VR6, this having been demonstrated by bombardment tests.
Implementation Example 2:
A steel sheet blank with a thickness of 6.5 mm has the following fractions of alloying elements:
0.25 - 0.4 $ C
0.0 - 1.0 % Ni 0.2 - 0.4 % Si 0.0 - 2.0 o Mn 0.0 - 0.55% Mo 0.0 - 1.1 o Cr.
This steel sheet blank is heated to an austenitizing temperature in the amount of 970°C and is immediately inserted into the press die and formed as a result of the closing of the press die. The press die has previously been cooled to approximately 70°C. As a result of the shock-like cooling due to the optimized dissipation of a large part of the heat from the steel sheet blank to the press die, the formation of a sufficient hardness structure occurs. Consequently, after the conclusion of the forming operation, the press die can be opened and the further cooling of the three-dimensionally formed armoring component can be carried out at room temperature.
A subsequent heat treatment is dispensed with. The three-dimensionally formed armoring component obtained corresponds to bombardment class VR6, this having been demonstrated by bombardment tests.
The cooling of the formed component is an integral part of the hardness treatment and therefore takes place in the closed press die.
Preferably, the forming in the press die takes place such that, during a pressing operation, with the formed steel sheet blank bearing over its full area against the impression of the press die, the rate of cooling of the austenitized or partly austenitized steel sheet blank is as far as possible above the critical cooling rate.
Alternatively to this method variant, it is possible, furthermore, that the austenitized steel sheet blank, after being inserted into the press die, is first formed and held in complete contact with the press die, the press die being cooled at least to approximately 70°C before the forming process. After the forming process, the further cooling of the formed steel sheet blank is carried out, with the press die open or outside the press die in the ambient air. In this case, it is assumed that the shock-like cooling of the austenitized formed steel sheet blank in the precooled press die leads not only to the formation of the fundamental hardness structure, but also to a sufficient dimensional stability of the three-dimensional armoring component produced. In this case, the press die can be used at a higher frequency for the production of components with repeating accuracy.
Preferably, the steel sheet blanks used are sheets of hardenable and maraging steels.
The method provides for the initial hardness of the armoring steel during hardening in hardening oil to be higher than 45 HRC or for the hardness after artificial ageing to be higher than 45 HRC.
Three-dimensionally formed armoring components with high dimensional accuracy are obtained, in particular, in that, after the forming operation, the press die is held closed for a period of time of 50 to 500 seconds until the desired cooling temperature is reached. As a result, the component is held in calibration up to the complete formation of the hardness structure, as a consequence of which deformations due to thermal stresses can be largely ruled out.
The cooling rate via the contact of the formed steel sheet blank with the press die is influenced in that the press die consists of highly thermally conductive material, for example steel, and/or can be cooled by coolants, preferably, for example, water, ammonia and/or compressed air.
It is possible to subject the cooled and formed steel sheet blanks to final heat treatment in the form of an expansion and/or tempering process, annealing or age-hardening treatment.
Alternative to this, measures, such as hardening, age hardening or artificial ageing, are also possible as thermal retreatment procedures, depending on the alloy composition. These measures serve for compensating possible uneven distributions of the degrees of hardness in the component and consequently to rule out unreliability in safety against the effects of bombardments or explosions. The thermal distortion occurring during thermal retreatment is known to be about only 10% of the armoring components produced by means of welding technology.
It is particularly advantageous that hot forming and quench hardening of the austenitized or partly austenitized steel sheet blanks are carried out in one operation.
The advantages of the invention, when combined, are that, for the special case of the production of three-dimensionally formed armoring components for vehicle bodies, specific requirements regarding the production of hardened steels, such as are known for the production of tools or semifinished products, do not have to be fulfilled. This refers, for example, to resistance to rolling fatigue, wear resistance or the fatigue limit under alternating stresses.
It may be assumed that the body of a vehicle of the special protection class is distorted completely or at least in respect of the loaded armoring components after being subjected for the first time to load by bombardment or explosion. In light of these particular requirements, the armoring components to be produced must have, in particular, continuous or full-area quality and, if possible, not require a mechanical remachining of the surface of the three-dimensionally formed armoring component. The proposed method takes these particular requirements into account to a high degree. As compared with known welded structures, three-dimensionally formed armoring components of high quality are obtained in a comparatively simple way by conjoining a hot forming process with a hardening process, starting from sheet blanks which have previously been pretreated in an austenitized or partly austenitized state.
In accordance with the desired protection class, WO 2005/078143 - '7 - PCT/DE2005/000169 characterized by defined bombardment safety and possible safety against explosions, the aim is to achieve the required heat treatment parameters.
Some annealing steels for use in protective class VR6 in this case, by the application of the proposed method, achieve, even without subsequent heat treatment, all the protective requirements, including safety against explosions by hand grenades of the type DM51, without splinter outbursts on the rear side of armoring elements.
In the design of the press dies, care must be taken to ensure that sufficient heat dissipation can be ensured at every point on the formed steel sheet blank.
Furthermore, the flow properties of the material must be borne in mind, so that, during the forming operation, the component comes to bear under uniform surface pressure completely and uniformly against the impression of the die and thinnings of the material thickness are avoided. To stabilize the component during heat treatment, beads or stabilizing forms extending continuously may be embossed in the blank.
After the hot pressing or possible heat treatment, the final form of the component is cut out by means of a laser or preferably a water jet.
By means of the proposed method, then, three-dimensionally formed armoring components for different protection classes can be produced, and their wall thickness may even amount to more than 10 mm. By hot forming, then, armoring components for vehicle bodies can be implemented, which it has hitherto been possible to produce only as complicated welding structures with ballistic weak points in the weld seam region.
Owing to the high process reliability, the large-series use of the method for the production of three-dimensionally formed armoring components with high dimensional accuracy is possible.
WO 2005/078143 - g - PCT/DE2005/000169 The invention will be explained in more detail below by means of implementation examples.
Implementation Example 1:
A steel sheet with a thickness of 6.5 mm has the following content of alloying elements:
0.5% C
1.1 - 1.3% Ni 1.0 - 1.5% Si 0.5 - 0.6% Mn 0.1 - 0.5o Mo.
From this steel sheet, a sheet blank is obtained and is heated to an austenitizing temperature in the amount of 950°C. In this state, the sheet blank is inserted into the press die and is formed as a result of the closing of the press die. Within a total of 300 seconds, the quench cooling of the formed steel sheet blank to the die temperature takes place. The die may in this case be cooled by coolant. The closing pressure of the press die is maintained over the entire cooling time.
Subsequently, heat treatment takes place by annealing to the quality HRC 50. The three-dimensionally formed armoring component corresponds to bombardment class VR6, this having been demonstrated by bombardment tests.
Implementation Example 2:
A steel sheet blank with a thickness of 6.5 mm has the following fractions of alloying elements:
0.25 - 0.4 $ C
0.0 - 1.0 % Ni 0.2 - 0.4 % Si 0.0 - 2.0 o Mn 0.0 - 0.55% Mo 0.0 - 1.1 o Cr.
This steel sheet blank is heated to an austenitizing temperature in the amount of 970°C and is immediately inserted into the press die and formed as a result of the closing of the press die. The press die has previously been cooled to approximately 70°C. As a result of the shock-like cooling due to the optimized dissipation of a large part of the heat from the steel sheet blank to the press die, the formation of a sufficient hardness structure occurs. Consequently, after the conclusion of the forming operation, the press die can be opened and the further cooling of the three-dimensionally formed armoring component can be carried out at room temperature.
A subsequent heat treatment is dispensed with. The three-dimensionally formed armoring component obtained corresponds to bombardment class VR6, this having been demonstrated by bombardment tests.
Claims (11)
1. A method for producing a three-dimensionally formed armoring component for vehicle bodies by the production of sheet metal preforms from hardenable steel, with the thermal pre-treatment of these steel sheet blanks, the heating speed and heating temperature being selected at least until the austenitic or partly austenitic state dependent on alloy content is reached, and with subsequent press forming and, if appropriate, subsequent hardness or heat treatment of the formed armoring components, characterized in that the hot forming and quench hardening of the steel sheet blanks are carried out in one operation, in that the austenitized steel sheet blank is formed by means of a press die within a time of at most 90 seconds, in that the formed component is held in full-area contact with the press die, in that the cooling of the formed component takes place in the closed press die, and in that the cooling of the formed component in the closed press die takes place at a cooling rate which corresponds at least to the material-specific critical cooling rate.
2. A method for producing a three-dimensionally formed armoring component for vehicle bodies by the production of sheet metal preforms from hardenable steel, with thermal pre-treatment of these steel sheet blanks, the heating speed and heating temperature being selected at least until the austenitic or partly austenitic state dependent on alloy content is reached, and with subsequent press forming and, if appropriate, subsequent hardness or heat treatment of the formed armoring components, characterized in that the hot forming and quench hardening of the steel sheet blanks are carried out in one operation, in that the austenitized steel sheet blank is formed by means of a press die still in the austenitic or partly austenitic state, in that the formed component is held in full-area contact with the press die, in that the press die is cooled at least to approximately 70°C before the forming process, and in that, after the forming process, the further cooling of the formed steel sheet blank takes place without calibration, but with the pressing force being maintained, for the purpose of heat dissipation from the sheet blank in the press die.
3. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 1 and 2, characterized in that the steel sheet blanks used are sheets of hardenable and maraging steels.
4. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 2 and 3, characterized in that steels with an initial hardness of the armoring steel during hardening in hardening oil higher than 45 HRC or with a hardness after artificial ageing higher than 45 HRC are used.
5. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 1 to 4, characterized in that, during heating to the austenitizing temperature, the alloying elements are dissolved predominantly in the austenite.
6. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 1 to 5, characterized in that the heat treatment time and temperature for austenitization are selected as a function of the component material and material thickness in order to minimize scaling, skin decarburization and grain growth.
7. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 1 to 6, characterized in that the forming of the austenitized steel sheet blank takes place approximately at the austenitizing temperature dependent on alloy content or at temperatures at which the steel sheet blank is in the partly austenitized state.
8. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 1 and 3 to 7, characterized in that, after the forming operation, the press die is held closed for a period of time of at least 50 to 500 seconds in order to achieve the desired cooling temperature.
9. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 1 to 8, characterized in that the press die can be cooled by coolants, preferably water, ammonia and/or compressed air.
10. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 1 to 9, characterized in that the cooled and formed steel sheet blanks are subjected to a final heat treatment in the form of expansion and/or tempering.
11. The method for producing a three-dimensionally formed armoring component for vehicle bodies as claimed in one of claims 1 to 9, characterized in that the cooled and formed steel sheet blanks are finally retreated by tempering, hardening and tempering, age hardening or artificial ageing.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102004006093A DE102004006093B3 (en) | 2004-02-06 | 2004-02-06 | Method for producing a three-dimensionally shaped armor component for vehicle bodies |
DE102004006093.2 | 2004-02-06 | ||
PCT/DE2005/000169 WO2005078143A1 (en) | 2004-02-06 | 2005-02-03 | Method for producing a three-dimensionally formed armouring component for vehicle bodies |
Publications (1)
Publication Number | Publication Date |
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CA2558003A1 true CA2558003A1 (en) | 2005-08-25 |
Family
ID=34853400
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002558003A Abandoned CA2558003A1 (en) | 2004-02-06 | 2005-02-03 | Method for producing a three-dimensionally formed armouring component for vehicle bodies |
Country Status (6)
Country | Link |
---|---|
US (1) | US20070130772A1 (en) |
EP (1) | EP1711639B1 (en) |
AT (1) | ATE419401T1 (en) |
CA (1) | CA2558003A1 (en) |
DE (2) | DE102004006093B3 (en) |
WO (1) | WO2005078143A1 (en) |
Families Citing this family (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102005014298B4 (en) * | 2005-03-24 | 2006-11-30 | Benteler Automobiltechnik Gmbh | Armor for a vehicle |
DE102006035153A1 (en) * | 2006-07-29 | 2007-11-22 | Audi Ag | Auto body for armored motor vehicle, has multiple supporting body sections and bullet-proof armoring, where B-pillars are formed from ballistic operative material, which is ballistic steel |
DE102007019173B3 (en) | 2007-04-20 | 2008-05-29 | Benteler Automobiltechnik Gmbh | Method for press-forming and hardening a steel workpiece in a stamping machine comprises partially moving the stamps away from each other after deforming and passing coolant through the gap between the stamps and the workpiece |
DE102007039993A1 (en) | 2007-08-23 | 2009-02-26 | Edag Gmbh & Co. Kgaa | Structural part for use in vehicle e.g. passenger car, has ballistic plate three-dimensionally molded into piece by using process of hot deformation in molding press and hardened by using vacuum oven after hot deformation |
DE102008014914B4 (en) | 2007-08-23 | 2013-07-04 | Vps Vehicle Protection Systems Gmbh | Structural part for a vehicle armor |
DE102007039998B4 (en) | 2007-08-23 | 2014-05-22 | Benteler Defense Gmbh & Co. Kg | Armor for a vehicle |
DE102008010168B4 (en) | 2008-02-20 | 2010-04-22 | Benteler Automobiltechnik Gmbh | Armor for a vehicle |
DE102008012720A1 (en) | 2008-03-05 | 2009-09-10 | Benteler Automobiltechnik Gmbh | Armor for a vehicle |
DE102008035388B4 (en) | 2008-07-29 | 2011-01-20 | Benteler Automobiltechnik Gmbh | Method for producing a motor vehicle armor component |
WO2010061007A1 (en) * | 2008-11-03 | 2010-06-03 | Fundacion Labein | Method for hardening a component obtained by hot-forging and device used |
DE102009049584A1 (en) | 2009-10-16 | 2011-04-21 | Benteler Automobiltechnik Gmbh | Armored vehicle grill, has sectional strips cut from curable armor steel and heated to temperature above point, where strips are brought into final shape in press tool and are hardened in press tool |
DE102009053349B4 (en) * | 2009-11-17 | 2014-07-03 | Benteler Defense Gmbh & Co. Kg | Armored steel component |
DE102010009183B8 (en) * | 2010-02-24 | 2015-06-18 | Benteler Defense Gmbh & Co. Kg | Method for producing an outer wall, method for producing an armored motor vehicle and side wall of a motor vehicle |
DE102010050499B3 (en) * | 2010-11-08 | 2012-01-19 | Benteler Automobiltechnik Gmbh | Use of a wear-resistant steel component |
WO2012097976A1 (en) | 2011-01-17 | 2012-07-26 | Tata Steel Ijmuiden B.V. | Method to produce a hot formed part, and part thus formed |
DE102011109660B3 (en) * | 2011-08-08 | 2013-01-17 | Benteler Defense Gmbh & Co. Kg | Molded component, useful for armor of a person or an object e.g. building, comprises protective or armor steel alloys, and many partial areas of increased hardness and a partial area of increased ductility on one of the two surface sides |
DE102011114691A1 (en) | 2011-10-04 | 2013-04-04 | Benteler Defense Gmbh & Co. Kg | Three-dimensional partial hot-working and subsequently partial hardening of a workpiece, comprises partially heating a workpiece by a heating device to a temperature, which is greater than or equal to the workpiece-specific-temperature |
US9671199B1 (en) * | 2014-05-06 | 2017-06-06 | Premier Body Armor, LLC | Armor steel products and method for making same |
KR101665819B1 (en) * | 2014-12-24 | 2016-10-13 | 주식회사 포스코 | Steel material for heat treating, formed component having extra high strength and high fatigue resistance and method for manufacturing the formed component |
TWI655977B (en) * | 2018-02-14 | 2019-04-11 | 中龍鋼鐵股份有限公司 | Hot rolled test piece leveling device |
DE102019209666B4 (en) | 2019-07-02 | 2020-06-04 | Audi Ag | Structural components for armor |
DE102022105458B3 (en) | 2022-03-08 | 2023-05-11 | Benteler Automobiltechnik Gmbh | Protective housing and method for its manufacture |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2911408C1 (en) * | 1979-03-23 | 1990-03-08 | Thyssen Ind Ag Maschb | Method for producing ballistic protected articles, such as vehicle bodies or housings for tanks and articles produced by this method |
FR2652821B1 (en) * | 1989-10-09 | 1994-02-18 | Creusot Loire Industrie | HIGH-HARDNESS STEEL FOR SHIELDING AND PROCESS FOR PREPARING SUCH STEEL. |
DE4223895C1 (en) * | 1992-07-21 | 1994-03-17 | Thyssen Stahl Ag | Process for the production of thick armored sheets |
US5454883A (en) * | 1993-02-02 | 1995-10-03 | Nippon Steel Corporation | High toughness low yield ratio, high fatigue strength steel plate and process of producing same |
DE19743802C2 (en) * | 1996-10-07 | 2000-09-14 | Benteler Werke Ag | Method for producing a metallic molded component |
US5972134A (en) * | 1997-10-02 | 1999-10-26 | Benteler Ag | Manufacture of a metallic molded structural part |
DE19821797C1 (en) * | 1998-05-15 | 1999-07-08 | Skf Gmbh | Hardened steel parts used for roller bearing parts |
US6146472A (en) * | 1998-05-28 | 2000-11-14 | The Timken Company | Method of making case-carburized steel components with improved core toughness |
JP2003231915A (en) * | 2002-02-08 | 2003-08-19 | Jfe Steel Kk | Press hardening method |
US6723182B1 (en) * | 2002-11-14 | 2004-04-20 | Arthur J. Bahmiller | Martensitic alloy steels having intermetallic compounds and precipitates as a substitute for cobalt |
-
2004
- 2004-02-06 DE DE102004006093A patent/DE102004006093B3/en not_active Revoked
-
2005
- 2005-02-03 AT AT05726399T patent/ATE419401T1/en active
- 2005-02-03 EP EP05726399A patent/EP1711639B1/en not_active Revoked
- 2005-02-03 CA CA002558003A patent/CA2558003A1/en not_active Abandoned
- 2005-02-03 DE DE502005006377T patent/DE502005006377D1/en active Active
- 2005-02-03 US US10/588,620 patent/US20070130772A1/en not_active Abandoned
- 2005-02-03 WO PCT/DE2005/000169 patent/WO2005078143A1/en active Application Filing
Also Published As
Publication number | Publication date |
---|---|
EP1711639A1 (en) | 2006-10-18 |
WO2005078143A1 (en) | 2005-08-25 |
US20070130772A1 (en) | 2007-06-14 |
EP1711639B1 (en) | 2008-12-31 |
ATE419401T1 (en) | 2009-01-15 |
WO2005078143A8 (en) | 2006-11-30 |
DE502005006377D1 (en) | 2009-02-12 |
DE102004006093B3 (en) | 2005-12-01 |
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