KR880001381B1 - Surface coated high speed steel member - Google Patents

Abstract

A high speed steel substrate is coated with a thick layer comprising one or more of Ti carbide nitride carboxide and carbonitride two or more hard layers having thickness 0.2-3 microns and a metallic Ti layer interposed between the hard layers. The metallic Ti layer has thickness 0.1-1 microns. The total thickness of these layers is 2-15 microns. The coated steel member is useful as machining tool, etc. The hard layer is controlled to possible thinnest extent and divided into two or more parts to suppress the growth of a dendritic structure. In add., the divided hard layers are bonded together by the metallic Ti layer excellent in toughness and adhesiveness.

Description

Surface-coated high speed steel member

The present invention relates to a surface-coated high-speed steel member formed by alternating three or more layers of a hard layer and a metal Ti layer having excellent toughness, and forming an excellent wear-resistant surface coating layer with a strong bonding force on a high-speed steel base surface.

Titanium carbide (hereinafter referred to as TiC), titanium nitride (hereinafter referred to as TiN), titanium carbonitride (hereinafter referred to as TiCN), titanium carbonitride (hereinafter referred to as TiCNO) and titanium carbonate on the surface of the conventional high speed steel base The surface-coated high-speed steel member which forms the hard coating layer of 0.5-10 micrometers of the thickness which consists of one type | mold single layer or two or more types of layers of the group (henceforth collectively called Ti compound) consists of a cutting tool. It is used as.

In general, the inert coating layer of the conventional surface coating high speed steel member is formed at a low temperature by soybean physical vapor deposition (including plasma chemical vapor deposition) at a relatively low temperature below the annealing temperature of the high speed steel so that the heat treatment effect on the high speed steel is not lost. In the case of forming the hard coating layer, even if the hard coating layer is formed thick on the substrate, the expected wear resistance is not improved.

There are various reasons for this, but the treatment at low temperature by physical vapor deposition tends to make the hard coat layer into columnar crystal structure, so when the hard coat layer becomes thick, it becomes a long columnar tissue, and the fragility is significantly increased. It is thought that the desired wear resistance improvement cannot be obtained even if the thickness of the layer is simply increased in accordance with the weak bonding strength between the columnar crystals.

From the above point of view, the present inventors conducted a study to form a hard coat layer on the surface of high-speed steel by using physical vapor deposition (including plasma chemical vapor deposition) that can be processed at low temperature, and excellent adhesion to gas and excellent wear resistance. As a result, the thickness of one layer of thin film becomes thinner to suppress the development of columnar crystal structure, and at least two layers of this hard layer are formed, while at least between the hard layers, the adhesion between the gas surface and the hard layer is excellent and the toughness is excellent. If the surface coating layer has a multi-layered structure having three or more layers through this rich metal Ti layer and has a predetermined layer thickness as a whole, the excellent toughness and interlayer bonding strength of the electrometal Ti layer, for example, prevent the strong stress acting upon cutting. As a result of the quenching effect, the hard layer is also subjected to chipping (c It was found that there is no hipping, and that the layer thickness of each layer is thin but excellent wear resistance is ensured by hard layers of two or more layers.

Therefore, the present invention is based on the above-mentioned knowledge, and in the surface-coated high-speed steel member in which the surface-coated layer is formed on the surface of the high-speed steel body, the hard layer 2 having a layer thickness of 0.2-3 μm in which the electrical surface-coated layer is a Ti compound. It consists of alternating lamination | stacking of three or more layers with the metal layer of the layer thickness 0.1-1 micrometer which consists of a metal Ti interposed between more than a layer and at least an electric hard layer, and makes the total layer thickness 2-15 micrometers.

In the present invention, in the surface-coated high-speed steel member, in the formation of the hard layer by physical vapor deposition, the surface-coated layer has excellent abrasion resistance, and the metal component and the reactant gas line are reacted on the gas surface by the action of gas plasma or plasma. In this case, in the case of the metal Ti layer, nitrogen, oxygen, or excess contained in the atmosphere or reaction due to the influence of the reaction temperature and reaction temperature, or by the invasion of molecules or ions of the atmosphere gas or the reaction gas, or It is thought that carbon and the like are absorbed and stabilized in the metal Ti layer, and as a result, the crystal bonding force in the layer is enhanced, and the coating layer itself has excellent wear resistance and chipping resistance.

The reason why the thicknesses of the hard layer, the metal Ti layer, and the entire coating layer in the surface-coated high-speed steel member of the present invention are respectively limited as described above will be described below.

(a) stratum corneum

If the thickness is less than 0.2 μm, the desired excellent wear resistance cannot be secured. On the other hand, if the thickness exceeds 3 μm, the columnar structure will develop and the strength of the hard layer itself will be reduced. Therefore, the thickness is set to 0.2-3 μm.

(b) metal Ti layer

When the layer thickness is less than 0.1 μm, not only the strength of the hard layer itself and the bonding strength of the crystal layers constituting the hard layer can be secured, but also the firm bonding force between the layer and the gas surface cannot be secured. Insufficient chipping resistance can not be obtained. On the other hand, if the thickness exceeds 1 μm, the wear resistance of the coating layer itself is reduced, so that the layer thickness is set to 0.1-1 μm.

(c) coating layer

In order to obtain the desired wear resistance and chipping resistance, a minimum thickness of 2 μm is required. However, if the thickness exceeds 15 μm, the coating layer itself becomes weak, so the thickness of the entire coating layer is set to 2-15 μm.

In addition, the coating layer in the surface-coated high-speed steel member of the present invention can be formed by carrying out at a reaction temperature below the annealing temperature of the high-speed steel by a method such as a conventional molybdenum deposition method or a chemical vapor deposition method using a low-temperature plasma, moreover, in this case a hard layer The layers constituting the layer may be compositionally and continuously changed, and the formation of alternating hits between the hard layer and the metal Ti layer is desired for continuous formation in the same apparatus in order to ensure a more firm interconnect strength.

Next, the surface-coated high-speed steel member of the present invention will be described in comparison with the comparative example.

Example 1

As a high-speed steel, a blower tip made of JIS SKH-9 having a shape specified in JIS SNP 432 was prepared.

Next, a Ti holding part is installed in the vacuum chamber, and an ion framing device is used in which the Ti holding part is irradiated with an electric beam, and the evaporating Ti and the introduced gas are passed through the plasma. The surface was washed by plasma etching, and then Ar was changed into a mixed gas of N ₂ + CH ₄ + Ar and reacted at a heating temperature of 450 ° C. to form a hard layer having a thickness of 4 μm of TiCN. The obtained surface-covered trough-away tip (closed tip) is referred to as a comparative tip below)

Meanwhile, except that the thickness of the hard layer of TiCN was 1 μm, the coating tip was manufactured under the same conditions as those of the comparative coating tip, and the thickness of the introduction gas was changed to Ar on the electrically hard layer. m metal Ti layer was formed, and then, under the same conditions, _two hard layers having a thickness of 1 μm TiCN and a layer thickness of 0.5 μm metal Ti were repeatedly formed by repeated introduction of N ₂ + CH ₄ + Ar mixed gas and Ar. The present invention covered flyaway tip (hereinafter referred to as the present invention coating tip) was prepared by forming an alternating stack of 5 layers as a whole, namely 5 layers, and forming a surface coating layer having a total thickness of 4 μm.

Next, with respect to the above-mentioned drawer tip (hereinafter referred to as a non-coated tip) without a metallic Ti layer and a TiCN layer prepared as a coating tip, a comparative coating tip, and an ultrahard alloy base material for cutting tools obtained as a result, Using a 44-inch collada, the outer diameter cutting test was performed under conditions of round bar of S45C (hardness H _D 190), cutting speed 20m / min, and 0.1mm / rev cutting oil. The cutting time to reach was measured and the wear state of the surface coating layer was observed. The results are shown in the first table.

As shown in Table 1, it can be clearly seen that the tip of the present invention shows no abnormal wear, an extremely long cutting time of 3 times that of the non-coated tip and 4.5 times that of the uncoated tip, and excellent cutting performance. .

Example 2

The same high shear steel tip as in Example 1 was used. The ion fritting apparatus applied to Example 1 on the surface thereof, and a spiting apparatus for sputtering a Ti-gel made in a vacuum vessel in a predetermined atmosphere (sputtering apparatiis) ) And the mixed gas is introduced into the plasma generated in the reaction vessel to perform a chemical reaction, and by using a plasma chemical vapor deposition apparatus for chemical vapor deposition, the Ti layer and the hard coating layer of the layer thicknesses shown in Table 2 are formed. Inventive coating tips ab and comparative coating tips ac were prepared respectively.

In addition, the comparative coating tip a is a coating layer composed of one hard layer made of TiCN without forming a metal Ti layer, and the comparative coating tip b is a coating layer in which the layer thickness of the metal Ti layer as the second layer deviates from the range higher than the scope of the present invention. The comparative coating tip c is composed of a coating layer in which the layer thickness of the hard layer of TiC, which is the second layer, is out of the range of the present invention.

The outer diameter cutting test was carried out under the same conditions as in Example 1 for the coating tip af and the comparative coating tip ac of the present invention, and the cutting time until the drawing wear of the tip reached 0.3 mm was measured. Observed and merged in the second table.

[Table 2]

As shown in the comparison coating tip ac from the results shown in Table 2, the cutting time is extremely short even in the case where there is no formation of the metal Ti layer or the formation of the metal Ti layer, the thickness of the two layers becomes too thick. In addition, it is evident that the surface coating layer is abnormally worn or the cutting finish is caused by severe chipping wear, resulting in the cutting stop. It was normal.

Example 3

As the high-speed steel, the same waste type tips as used in Examples 1 and 2 were prepared, and the sputtering method, which is a conventional coating method, was used on the surface of the tip to form a laminated coating layer having the configuration shown in Table 3, respectively. Comparative coating tips A were prepared, respectively.

[Table 3]

Next, the present invention coating tip AC and comparative coating tip A were subjected to the outer diameter turning test under the same conditions as in Example 1, and the cutting time until the drawing wear of the tip reached 0.3 mm and At the same time, the wear state of the coating layer was observed. As a result, it collectively displayed in the 3rd table | surface.

As apparent from the results shown in Table 3, the tip AC of the present invention has a comparative coating tip A in which the surface coating layer is made of two layers of the metal Ti layer and the TiCN hard layer, and the layer thickness of the hard layer is out of the range of the present invention. It showed a significantly longer life time compared with that of the coating layer and was normal in abrasion state of the coating layer.

As described above, the surface-coated high-speed steel member of the present invention has a structure in which the surface coating layer is an alternating stack of three or more layers of the metal Ti layer and the hard layer, and furthermore, the metal Ti layer is strongly bonded to the hard layers and has excellent toughness. For example, the cushioning effect is also applied to the strong stress acting during cutting, so that the coating layer does not cause chipping, and excellent wear resistance can be secured by lamination of the hard layer. .

Claims (1)

In the surface coating high-speed steel member formed by forming a surface coating layer on the surface of a high-speed steel body, the layer thickness of 0.2-3 μm in which the surface coating layer is one or two or more of Ti carbide, nitride, carbonitride, carbonate and carbonitride is hard. Surface coating high speed steel, characterized by consisting of three or more layers of alternating layers with at least a layer of metal Ti with a thickness of 0.1-1 μm interposed between at least two layers and at least the hard layer, and having a total layer thickness of 2-15 μm. absence.