JPH06207297A - Method and equipment for plating strip material with zinc - Google Patents

Abstract

PURPOSE: To produce a galvanized strip having stable and uniform quality by measuring an iron component quantity on the strip surface where a zinc layer is formed and heat treatment is applied in a furnace opened at both ends, and controlling calorific value in the heat treatment furnace.

CONSTITUTION: The steel strip 1 with the zinc layer formed by a zinc coating means (galvanizing means) 4 is taken out through a scraping-out means 7, the furnaces 10, 11 opened at both ends as the heat treatment means 13 and a cooling means 15. At this time, a measuring means 16 is arranged on the downstream side of the cooling means 13 and the iron component quantity in the galvanized Zn-Fe layer is measured over the whole width and the whole length of the strip 1 by an on-line X-ray fluorometry. The measured actual value is inputted into a control computer 18 and compared with a reference inputted value to control the calorific value in the furnaces 10, 11 opened at both ends through an automatic control means 19. In this way, the stable and uniform Zn-Fe layer can be formed on the strip 1.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to continuous coating of a strip material, particularly a steel strip, with zinc by a continuous treatment with a zinc bath by an electrolytic method or a hot dip galvanizing method, and then Z coating.
Performing heat treatment in a double-ended open furnace to form an n-Fe layer, further on-line control of the zinc layer, and performing strip galvanizing and galvanizing methods to control the galvanizing process as a function of online control parameters. Regarding galvanizing equipment.

[0002]

2. Description of the Related Art A galvanizing process of this kind for the production of so-called heat treated (galvannealing) galvanized strips, i.e. steel strips coated with a thermally post-treated metal, is described, for example, in EP-A 473. , 154, the galvanized strip is continuously galvanized in a continuous process. Therefore, the strip is formed as a double-ended open furnace for galvannealing and soaking (soaking) after passing through the galvanizing section (zinc bath + extraction system of hot dip galvanizing plant, galvanizing cell of electrolytic galvanizing plant). Is guided into the furnace. This furnace can be, for example, an electric induction furnace or a gas furnace.

[0003]

The galvannealing process converts a pure zinc layer into a Zn-Fe layer by diffusion of iron. Products with different mechanical properties (toughness, strength, etc.) are manufactured depending on the amount of iron component of Zn-Fe alloy, and their application fields (wear resistance, weldability, paintability, corrosion resistance, deep drawing) Characteristic). For example, as described in the above-mentioned EP-A 473,154, the iron component is measured by an appropriate measuring means (for example, X-ray fluorescence, X
Continuous, ie online, by means of line diffraction or other similar technique) and the measurement result is Zn-F of the iron component.
The average value in the thickness direction of the e layer is given. For the quality of the product, it is very important that the Zn-Fe layer has completely finished the reaction, that is, that iron penetrates to the surface of the Zn-Fe layer and forms a stable phase with zinc. The present invention is
By further developing the above-mentioned galvanization method, it is possible to obtain a galvanized strip having a completely reacted layer structure, directly and immediately intervening in the manufacturing process, while minimizing the occurrence of defective products, The purpose is to provide a homogeneous galvanized strip.

[0004]

The process according to the invention, inter alia, automatically incorporates both planned changes in process parameters and unintended changes in these parameters, so that the manufacturing process does not require human intervention. It is always optimized without. According to the present invention, the above object is to determine a certain value of the iron component amount of the Zn-Fe layer as a reference input value, and compare the actual iron component value in the Zn-Fe layer with the reference input value. By changing the calorific value of the open-ended furnace as the manipulated variable, these 2
It is achieved by compensating for the deviation of two values. The present invention is based on the finding that the diffusion process of the iron component (iron component diffusivity) into the zinc layer depends on the temperature in the double-ended open furnace and the heat treatment time. Temperature control in a double-ended open furnace has a crucial influence on the structure of the galvannealing layer and thus on the mechanical properties of the product. By the way, the temperature detection of the strip in the area inside the galvannealing furnace is not practical in practice because there is no non-contact type inexpensive measuring means that can detect the temperature with sufficient accuracy under the condition of the inside of the furnace. It is possible. In an embodiment of the invention, the temperature in the furnace is adjusted indirectly from the heating value, thereby ensuring a very uniform quality of the galvanized strip.

According to a preferred mode of operation of the present invention, the amount of radiation emitted by the strip surface (radiation intensity or power), in addition to determining the actual value of the iron content in the Zn--Fe layer, Measured by at least one pyrometer during or after heat treatment. As a result, Zn-
Irrespective of the amount of iron component in the Fe layer, it was determined whether the reaction of said layer was completed (at least galvannealed) with respect to at least the surface or whether pure zinc was still present on the surface, resulting in both ends. The calorific value of the opening furnace is adjusted. Preferably, a plurality of pyrometers are continuously arranged in the transport direction along the strip transport path to perform measurement, thereby
By determining the place (position) where the reaction of the n-Fe layer is completely finished and controlling the heat generation amount of the double-ended open furnace, this position is set as a desired position on the strip transport path that functions as a reference input value. It According to a preferred mode of operation, the value of the iron component of the Zn-Fe layer is determined as another reference input value in addition to the reaction completion position, Z
The set value of the iron component of the n-Fe layer is compared with the reference input value,
The deviation is compensated by automatic control by changing the calorific value of the double-ended open furnace as the manipulated variable.

Preferably, the control is performed by a computer that stores the control error, and by a closed loop control circuit that executes various instructions to control the heating value of the double-ended open furnace. The computer measures the dimensions of the strip, the chemical composition and structure of the base material of the strip, the thickness of the zinc layer, the composition ratio of the zinc bath, such as the amount of aluminum component, the strip speed, and the strip temperature at the entrance of the double-ended furnace. Control is executed by inputting various parameters such as room temperature. In a preferred embodiment of the present invention, the calorific value of the double-ended opening furnace and the temperature inside the furnace are individually adjustable in each heating zone. When the amount of iron component in the iron-zinc alloy or the amount of radiation emitted from the surface is a different measurement value in the width direction of the strip, it is preferable to make the heat generation amount different in each region in the width direction of the strip.

In another embodiment of the present invention, the heat generation amount can be adjusted differently in each heating zone continuously arranged in the strip conveying direction, and the heating rate of the strip and the predetermined temperature can be adjusted. The soaking time is variable to achieve optimum strip quality. More suitably, the radiation amount and / or the iron component amount may be measured at a plurality of positions in the strip width direction. The equipment for carrying out the galvanizing method according to the present invention comprises a strip transport means for continuously transporting strips along a transport path, a heat treatment means for continuously arranging strips constituted by a galvannealing furnace, and a strip transport means. It is arranged in the heat treatment means on the road or in the downstream thereof, and comprises a measuring means for measuring the amount of iron component in the zinc layer, while the measuring means is connected to an automatic control means,
The automatic control means is characterized in that it is connected to the heating means of the heat treatment means via a control line. The automatic control means is preferably connected to a process control computer in order to incorporate and control a plurality of parameters which influence the quality of the paint strip. In order to determine whether the reaction of the Zn-Fe layer has been completed, at least one additional radiation measuring means configured as a pyrometer is provided inside or downstream of the heat treatment means and an automatic control means. Connected to.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As is apparent from FIG. 1, a galvanized steel strip 1 has a strip transport path from a take-out station (not shown) to an take-in station by means of strip carrying means consisting of a plurality of strip guide rollers 2. 3 is continuously conveyed. Strip transport path 3
Along the way, the steel strip is first coated with zinc 4
Reach In the present embodiment, the zinc coating means 4 comprises hot dip galvanizing means. This galvanizing means comprises a zinc bath 5 and a zinc bath 5 in the strip transport direction 6.
And stripping means 7 for ensuring a constant zinc layer of uniform thickness across the width of the strip. Next, the steel strip 1 includes a thermal type thickness measuring device 8 and a temperature measuring means 9 for measuring the thickness of the zinc layer, and the heat treatment means 1 comprises two end-opening furnaces 10 and 11.
Introduced in 3. In a first double-ended furnace 10, the steel strip 1 is first heated to the required galvannealing temperature. The steel strip 1 is maintained at a constant galvanile temperature in another double-ended open furnace 11 arranged in the next stage.

Steel strip 1 from a second open-ended furnace 11
Then, the radiation amount of the completely galvannealed steel strip 1 is measured by the pyrometer 14. Subsequently, the cooling means 15 is arranged along the strip conveying means. The strip conveying path 3 downstream of the heat treatment means 13 is provided with another measuring means 16 for measuring the amount of iron component in the Zn-Fe layer. Preferably, this measuring means is a double arrow in the figure. As indicated at 17, the strip is displaceable in the width direction so that the measurement can be performed at various positions in the width direction. It is preferable that this measuring means be capable of performing measurement by a measuring method using X-rays. An automatic controller 19 in combination with a process control computer 18 cooperates with a heat treatment means 13 composed of two double-ended open furnaces 10 and 11, as shown by a double-headed arrow 20, to adjust the heat generation amount of each furnace.

The operation of the above equipment is as follows. Due to its high affinity for iron, the aluminum dissolved in the zinc bath 5 first forms an iron-aluminum layer (Fe ₂ Al ₅ ) on the steel strip, whereby the iron component of the steel strip 1 and the zinc Prevent layer reaction.
The system consisting of the steel strip 1, the Fe-Al layer and the liquid zinc layer enters the first double-ended open furnace 10, where there
It is heated to a temperature in the range of 700 ° C. In the second open-ended furnace 11, the steel strip 1 is maintained at a predetermined temperature or heated to a higher temperature. The pure zinc layer is converted into a zinc-iron layer in the process of diffusion of iron into the zinc layer induced thereby. As a result, the Fe-Al barrier layer formed first in the zinc bath is destroyed by Zn-Fe growth at the grain boundaries of the substrate, and Zn-F
Initiate mushroom-shaped growth of the e-complex. Depending on the iron content, different metallographic phases with different properties are formed.

The most important phases are listed in the table below. ─────────────────────────────────── Phase% Fe Crystal structure Hardness (MPa) η <0.03 Hexagonal system 300-500 ζ 5-6 Monoclinic system 1800-2700 δ 7-12 Hexagonal system 2500-4500 γ 21-28 Cubic system 4500-5500 ────────────── ────────────────────── As is clear from the above table, as the iron content increases, the phases become harder and brittle. This means that a larger amount of wear is generated in the subsequent deformation (for example, deep drawing), which means that the adhesive force of the Zn—Fe layer is significantly weakened. In the case of electrolytic galvanizing equipment, the treatment process is the same, but the amount of aluminum component is not important. In order to adjust the optimum iron content, ie the iron content which allows the deformation of the galvanized steel strip 1 without any problems, the iron content of the Fe-Zn layer is in addition to the complete reaction control and determination. Therefore, it is advantageous to determine by an on-line X-ray fluorescence measurement with the measuring means 16, which is preferably done over the entire width and the entire length of the strip. The actual value of the iron content of the Zn-Fe layer is the Zn-Fe preset as the reference input.
The iron component value of the layer is compared with the automatic control means 19.
The deviation that may occur is compensated for by the automatic control means 19 by changing the amount of heat generation as the operating variable of the first and second double-ended open furnaces 10, 11. For example, when the measured amount of iron component is less than the desired value, the calorific value of the double-ended open furnace becomes zero or falls below a preset value (dead zone), as described below with reference to FIG. Will be increased up to.

Curve I shows the relationship between the iron component of the Zn-Fe layer and the amount of heat generation. This is empirically determined and, for example,
It is applied to the control computer (automatic control means 19) as a formula of internal correlation and table format. Steel strip 1
If B behaves exactly as in curve I, the preferred value of the iron component Fe ₁ (point A) is achieved by adjusting the heating value to P ₁ . If the steel strip 1 behaves a little differently as shown by the curve II due to, for example, fluctuations in ambient temperature, fluctuations in the transformer output for electric heating of a double-ended furnace, and other external factors, the iron content is set to the set value Fe.
_The value Fe ₂ (point B) deviates from ₁ . Therefore, the heat generation amount is, for example, the degree of increase dp / d at the point A ′ of the curve I.
As a function of Fe, for example, the equation k × (dp / dFe) ×
It is changed according to ΔFe. When the gain factor k is 1, the changed heat generation amount is input at P ₂ in the figure.
Thereby, the iron component has a more preferable value (point C).
The control is as long as the deviation is detected (Fe component ≠ Fe ₁ )
Done.

Irregular iron profile in the strip width direction is caused by various causes: 1) uneven feed thickness 2) strip lateral bulge 3) strip profile 4) strip width direction Non-uniform heat generation 5) Non-uniform temperature distribution in the strip width direction at the strip entrance to the galvanizing furnace. First, the coating thickness is adjusted uniformly within a narrow tolerance in the strip width direction (known layer thickness control process). Despite the uniform layer thickness in the strip width direction, the non-uniform distribution of the iron component in the strip width direction is caused by the causes 2) to 5). The uneven heat input to the steel strip 1 results in an iron component distribution as shown in FIG. 3, for example, even if the coating thickness is uniform in the strip width direction. What is required is a coating thickness and iron component distribution that are as uniform as possible in the strip width direction (and length direction). By reducing the heating value of the double-ended furnaces 10, 11 mainly in the heating zone 12 acting in the width direction of the strip, or by increasing the heating value in the heating zone 12 'mainly acting on the edges of the strip. The uniformity of the iron component in the width direction can be improved and a complete reaction over the entire width of the strip can be guaranteed.

Several further factors are taken into consideration by the processing steps according to the invention: 6) Thickness of the zinc layer The diffusion path and the structure of the coating also change with the layer thickness. Under equal furnace calorific conditions, thinner layer thickness (thinner coating layer) results in higher iron content. This is also seen at the edges of the strip, which may have different layer thicknesses than the central region of the strip. 7) Aluminum component in the zinc bath The aluminum dissolved in the zinc bath 5 adheres, inter alia, to the following two layers: a) The boundary layer between the iron substrate and the zinc layer: its high affinity for iron. Due to its properties, in a zinc bath the aluminum first forms a Fe ₂ Al ₅ barrier layer, which is a brittle Z
Prevents premature growth of the n-Fe phase. This barrier layer must be destroyed in the galvanizing process to initiate zinc-iron growth. b) Surface oxide layer: Most of the aluminum is present as Al ₂ O _{3 on} the surface of the zinc layer. 8) The speed at which the steel strip 1 is moved in the installation: this affects the time of presence (soaking time) of the steel strip 1 in the double-ended furnaces 11, 12 and thus the temperature control of the steel strip 1. give. Therefore, the reaction time changes, which in turn affects the iron content. 9) Chemical composition and structure of steel strip 1: Zn-F
Since the growth of the e-composite first begins at grain boundaries, the reactivity depends on the composition and structure of the substrate. 10) Additionally, the strip dimensional parameters influence the heat input and thus the diffusion conditions.

According to the present invention, all the factors that influence the amount of iron components as described above can be taken into consideration by inputting all the data that determine these factors into the control computer 18, and the automatic control means 19 These factors are taken into account by connecting the automatic control means 19 to the control computer 18 in determining the heating value of the heat treatment means 13 according to. Intentional changes in the process parameters, such as changes in the dimensions of the steel strip 1, changes in the chemical composition of the steel strip 1, changes in the thickness of the zinc layer, changes in the transport speed of the steel strip 1, etc. It is output to the control computer 18 in order to consider (determine) the heat generation amount. Since the Zn-Fe layer rapidly changes as soon as the Zn-Fe layer contains iron as the zinc layer is converted into the Zn-Fe layer, the radiation dose of the pyrometer 14 is measured by the pyrometer 14. It is necessary for the evaluation of. Pyrometer 14
It is arranged within the range of the heat treatment means 13 (for example, between the galvanizing furnace 10 and the soaking furnace 11) or at a subsequent stage. This measurement serves to give information about the radiant energy emitted from the surface of the steel strip 1, ie its Zn--Fe layer, which radiant energy is a function of the temperature and the radiation coefficient of the surface layer. The emission coefficient of pure zinc surface is less than 0.2, while that of fully reacted Fe-Zn surface is about 0.6. If the Zn-Fe layer has not completely reacted at the position of the pyrometer 14, the calorific values of the open-ended furnaces 10, 11 are connected to the process control computer 18.
An automatic control means 19 to which the measured value of the pyrometer is input is controlled to increase until the pyrometer detects a complete reaction. In this case, the calorific value is an operation variable amount of the control process.

When the complete reaction has taken place, ie due to the large change in the radiation dose when the iron penetrates to the surface of the zinc layer, it is possible to recognize the site in the strip transport direction 6 at which the complete reaction has been realized. it can. This is possible, for example, by arranging two or more pyrometers in the strip transport direction 6 at suitable intervals. By knowing the sudden increase in the radiation amount due to the complete reaction of the Zn-Fe layer and measuring the radiation intensity by the pyrometer 14, the position where the Zn-Fe layer has completely reacted is determined in the strip transport path 3. Can be detected. Open-ended furnace 10,
Each calorific value of 11 is controlled by the automatic control means 19 so that a complete reaction is realized at a predetermined preferred position. Another method of recognizing the position where a complete reaction has occurred in the strip transport direction may be to compare the pyrometer measurements with some thermal model calculations. For this reason, the pyrometer measurement is performed on the basis of the empirically determined change in the radiation amount of the pure zinc layer, and the second time on the empirically determined change of the radiation amount of the completely reacted Zn-Fe layer. Based on the degree. The result of this calculation gives two different pyrometer temperature values for the strip running according to different radiation coefficients. By comparing these two values obtained by model calculation of the temperature at the time of entry of the steel strip into the heat treatment means and the temperature which can be calculated from the heat value of the heat treatment means, which are carried out in parallel for the strip part in question.
It can be found which of the four pyrometer temperature values corresponds to the calculated temperature. This temperature value is regarded as the correct temperature of the running steel strip 1. The associated radiation dose will indicate whether the steel strip is still in the pure zinc layer or the layer has completed the reaction.
The heat generation amount of the heat treatment means is controlled at the position of the pyrometer 14 so that the reaction is completed.

For the quality of the product, the Zn-Fe layer is completely reacted, ie zinc forms a stable phase with iron on the surface of the steel strip 1 coated by the infiltration of iron during the diffusion process. What you do is most important.
Although the iron component of the Zn-Fe layer cannot be directly and immediately derived only by the information on the complete reaction of the Zn-Fe layer, the amount of iron component is still very important for the properties of the product, and the two information It is effective to adjust the calorific value distribution over the entire length of the heat treatment means based on the combination of the amount, that is, the amount of iron component of the Zn-Fe layer and the determined emissivity. Each of the control methods described above is operable within a closed control circuit. The variable (manipulation amount) that can be operated by the heat treatment means 13 is calculated by the computer of the automatic control means 19 from the deviation between the measured value and the set value of the radiation amount and the actual value, and further, if desired. To be done.
In the calculation, high temperature measurement (layer thickness measurement) and / or temperature measurement downstream of the double-ended opening furnace 10, strip speed, and various measurement values from heat input in each zone of the heat treatment means 13 are indicated by arrows 20 and 21. As required to increase the accuracy of the control process.

The calculation of the manipulated variable is performed by using a certain control model, and the model can be changed according to the measuring device and control means used in each facility. In a specific configuration of an equipment, the control model is described by model parameters. These model parameters differ depending on different base materials, strip size specifications, the amount of aluminum components in the zinc bath, etc. These base material, strip size specifications, and the amount of Al component in the zinc bath are transmitted to the control computer 18 by a superset computer (for example, a production planning computer) or an external input unit. These data are transmitted to the computer of the automatic control means 19 together with the set values applied to the product to be manufactured (see arrow 22). The computer of the automatic control means 19 calculates each control command by considering these model parameters of the control model. Depending on the structure of the double-ended open furnaces 10 and 11, the total calorific value and the calorific value in each furnace part (zone in the length direction of the strip) are adjusted within a predetermined limit range. As shown in FIG.
Since it is possible to compensate for the shift of the Fe component that may occur despite the uniform thickness of the Fe layer, the distribution of the heat input of the strip, that is, the both-end opening furnace 1 in the strip width direction
It is particularly advantageous if the heating value of 0, 11 can be adjusted within a predetermined control range.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a facility for galvanizing a strip.

FIG. 2 is a graph showing the dependence of iron components on the amount of heat generation.

FIG. 3 is a graph showing changes in the iron component in the Zn—Fe layer in the strip width direction.

FIG. 4 is a graph showing the dependence of the radiation dose on the soaking time.

[Explanation of symbols]

1 ... Strip, 5 ... Zinc bath, 7 ... Scraping means, 8 ...
Heat thickness measuring means, 10, 11 ... Both end opening furnace, 13 ... Heat treatment means, 14 ... Pyrometer, 15 ... Cooling means, 16 ... Measuring means, 19 ... Automatic control means, 18 ... Process computer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Josef Fadel Austria, Ar-4493 Wohlfern, Stifterstraße No. 6 (72) Inventor Manfred Machek Austria, Ar-4030 Linz, Lillienthalstraße No. 3 (72) ) Inventor Alois Stattlebauer Austria, Ah-4040 Linz, Asan Gerweg No. 20 (72) Inventor Klaus Zemann Austria, Ah-4020 Linz, Croer Tengasse No. 33

Claims (14)

[Claims] 1. A method of galvanizing a strip material such as a steel strip having a strip surface and conveyed along a strip conveying path, the strip being formed by a zinc bath used in an electrolytic method or a hot dip galvanizing method. The surface is continuously coated with zinc to form a zinc layer on the strip, and the strip having the zinc layer is heat-treated in a furnace having openings at both ends to form a Zn-Fe layer, and further the iron component in the zinc layer. In the galvanizing method of strip material, which controls the zinc layer online by measuring the amount, and obtains the actual value of the iron component for controlling the zinc plating process as a function of the iron component in the zinc layer. , Determining the iron component reference input value in the Zn-Fe layer, comparing the actual iron component amount of the Zn-Fe layer with the iron component reference input value, and deviating these two amounts. Detecting, zinc plating of the strip material, characterized by comprising automatic control means for compensating for the deviation by changing the heating value of the open ends furnace as an operation amount. 2. Equipped with at least one pyrometer for measuring the radiation dose on the strip surface during or after the heat treatment and for providing information for determining the reaction completion of the Zn--Fe layer. The method for galvanizing a strip material according to claim 1, wherein: 3. A plurality of pyrometers are continuously arranged in the strip conveying direction to determine the position where the reaction of the Zn—Fe layer is completed, and at least the calorific value of the double-ended open furnace is controlled, thereby controlling the position. 3. The method of galvanizing a strip material according to claim 2, wherein is set as a boundary position in the strip transport direction at which the reaction of the Zn-Fe layer should be completed. 4. A closed control circuit for executing the above control and a computer, wherein the computer stores the above deviation and controls the heat generation amount of the double-ended open furnace through execution of various commands. The method for galvanizing a strip material according to claim 1. 5. The computer comprises the dimensions of the strip material, data such as at least the chemical composition and structure of the base material forming the strip, the thickness of the zinc layer, the composition of the zinc bath such as the amount of aluminum component, and the strip. The method of galvanizing a strip material according to claim 4, characterized in that the transport speed of the strip material is used as a control factor. 6. The galvanizing method for strip material according to claim 5, wherein the computer further uses additional parameters such as strip temperature and room temperature at the inlet of the double-ended opening furnace as control factors. 7. The double-ended opening furnace has a plurality of heating zones, and the calorific value and the internal temperature of the double-ended opening furnace can be adjusted to be different in each of these heating zones. Zinc plating method for strip material. 8. The galvanizing method for strip material according to claim 7, wherein said heating zones are arranged adjacent to each other in the width direction of the strip. 9. The galvanizing method for a strip material according to claim 7, wherein the heating zones are continuously arranged in the strip conveying direction. 10. The zinc of strip material according to claim 7, wherein at least one of the amount of iron component and the amount of radiation is measured at a plurality of points distributed in the width direction of the strip material. Plating method. 11. A facility for galvanizing a strip material such as a steel strip having a strip surface, the strip transport means for guiding the strip along the strip transport path, and the strip transport means disposed on the strip transport path. Zinc coating means for applying zinc to obtain a coated strip having a zinc layer; heat treatment means arranged downstream of the zinc coating means and comprising a double-ended open furnace including heating means;
In a galvanizing facility for strip material, which is arranged downstream of the heat treatment means and has an iron content measuring means for measuring the iron content of the zinc layer, an automatic control means coupled with the iron content measuring means, and an automatic control means And a control line that connects the control means to the heating means of the heat treatment means. 12. The galvanizing equipment for strip material according to claim 11, further comprising a process computer connected to the automatic control means. 13. A pyrometer, further comprising at least one radiation measuring means arranged on the strip transport path downstream of the heat treatment means, said radiation measuring means being connected to said automatic control means. 11. A strip material galvanizing facility according to item 11. 14. A pyrometer, further comprising at least one radiation measuring means arranged on the strip transport path in the heat treatment means, said radiation measuring means being connected to said automatic control means. Characteristic strip material zinc plating method.