JPS63270467A - Coated ferrous alloy excellent in surface accuracy and its production - Google Patents

Abstract

PURPOSE:To improve the adhesive strength and peeling resistance of an outside Ti-compound layer at the time of forming a hard Ti-compound layer on the surface of an Fe-base alloy, by interposing a layer consisting of Ti compound and Fe-Ti intermetallic compound between Ti-cpd. layer and Fe-alloy. CONSTITUTION:At the time of forming a layer of hard Ti compound, such as TiC, TiCN, TiCO, TiCNO, and TiN, on the surface of an Fe-base alloy, the Fe-base alloy is placed in a reaction chamber, to which, while applying heating up to 800-1,100 deg.C, Ti halide such as TiCl4 and hydrocarbon such as H2 and CH4 and, if necessary, one kind among N2, NH3, CO, hydrazine, and CO2 are supplied so as to form an intermediate layer consisting of Ti compound and Fe-Ti intermetallic compound, such as TiC-FeTi and TiCN-Fe2Ti, to <=1mum thickness. Successively, a hard coating layer of TiC, TiCO, TiCN, TiN, etc., is formed on the above-mentioned intermediate layer to 1-20mum thickness. In this way, a coating layer consisting of hard Ti compound and excellent in wear resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to wear-resistant tool parts such as dies, plugs, rolls, punches or various molds, and drills.

Drilling tools such as taps, end mills and reamers, cutting tool parts such as turning tools and price tools, various tool parts such as scissors, razor blades and cutting blades, precision machine parts and for nuclear reactors, space development, semiconductors, etc. The present invention relates to a coated iron-based alloy with excellent surface precision that can be applied to special purpose parts such as chemical reaction equipment, medical equipment, etc., and a method for manufacturing the same.

(Prior Art) A coated iron-based alloy in which a coating layer of titanium carbide, titanium carbonitride, or titanium carbonitride oxide is formed on the surface of an iron-based alloy such as stainless steel, die steel, or high-speed steel has been put into practical use. Methods for forming a coating layer on the surface of an iron-based alloy can be broadly classified into chemical vapor deposition (CVD) and physical vapor deposition (PVD).

Of these, the latter coated iron-based alloy can be processed at low temperatures, but the coating layer tends to peel off when used under harsh conditions such as wear-resistant tool parts or cutting tool parts including drilling tool parts. There is. Additionally, there is a problem in that it is difficult to uniformly form a coating layer over the entire surface of a complex-shaped product due to the directionality of the deposit. On the other hand, the former coated iron-based alloy has better coating coverage than the latter, and is treated at high temperatures, so the coating layer has better peeling resistance. There is a problem in that interdiffusion becomes intense at the boundary between the two, resulting in variations in peeling resistance. However, since the peeling resistance of the coating layer is superior to that obtained by the PVD method, there are increasing expectations for stabilization of the coated iron-based alloy by the CVD method.

(Problems to be Solved by the Invention) The present inventors discovered that, while direct formation of a coating layer of titanium carbide on the surface of cemented carbide using the CVD method has been put to practical use without any problems, It was confirmed that the following problems occur when a titanium carbide coating layer is directly formed on the surface of the base alloy.

When a coating layer of titanium carbide is directly formed on the surface of an iron-based alloy by the CVD method, unevenness occurs on the surface of the coating layer, and this unevenness on the surface of the coating layer induces peeling of the coating layer, and there are problems with resistance. When applied as wear tool parts or cutting tool parts, there is a problem in that the processed surface becomes rough. Further, since the surface of the coating layer has irregularities, when the coated iron-based alloy is used in a mirror-like state like a roll, there is a problem in that it is difficult to make the surface of the coating layer a mirror-like surface.

The present invention solves the above problems. Specifically, the present invention has an intermediate layer made of a titanium compound and an iron-titanium intermetallic compound on the surface of an iron-based alloy, and an outer layer made of a titanium compound. The object of the present invention is to provide a coated iron-based alloy with excellent adhesion of the coating layer, peeling resistance of the coating layer, and surface roughness of the outer layer.

(Means for Solving the Problems) The present inventors have discovered that the cause of the unevenness on the surface of the coating layer that occurs when titanium carbide is coated on the surface of an iron-based alloy is, firstly, that the iron in the iron-based alloy is At the beginning of the CVD process, it diffuses into the titanium carbide coating layer and exists as iron metal.Secondly, a large amount of iron locally occurs near the interface between the iron-based alloy and the coating layer. It was confirmed that this was due to the fact that columnar crystals of titanium carbide developed in a fan shape from the location. Therefore, we were considering preventing the presence of iron alone in the coating layer, and discovered that if the iron diffused into the coating layer was made into an intermetallic compound with titanium, the surface of the coating layer would become smooth. That's what I got. Based on this knowledge, we have completed the present invention.

That is, the coated iron-based alloy of the present invention with excellent surface precision comprises a base of iron-based alloy, an outer layer made of at least one of titanium carbide, titanium carbonitride, titanium carbonate, titanium carbonitride oxide, and titanium nitride. In a coated iron-based alloy having an intermediate layer interposed therebetween, the intermediate layer comprises at least one of titanium carbide, titanium carbonitride, titanium carbonate, and titanium carbonitride oxide.
It is characterized by consisting of a seed titanium compound and an iron-titanium intermetallic compound.

The intermediate layer in the coated iron-based alloy with excellent surface precision of the present invention is, for example, Tic and Fe2Ti.

TiC, Fe2Ti and FeTi.

TiC and FeTi.

Ti(C,N) and Fe2Ti.

Ti(C,N), Fe2Ti and FeTi.

Ti(C,N) and FeTi.

Ti(C,N,O) and Fe2Ti.

Ti (C, N, O), Fe2Ti and FeTi.

Ti(C,N,O) and FeTi.

Examples include Tic, Ti(C,N), and Fe2Ti. The titanium compounds in the intermediate layer and the titanium compounds forming the outer layer mentioned here may be stoichiometric or non-stoichiometric, provided that these intermediate layers have an average thickness of 2 JLm or less. A coated iron-based alloy with excellent surface precision can be obtained.Although it varies depending on the application, an average thickness of 0.05 to Iμm or less improves the peeling resistance between the iron-based alloy and the outer layer. It is preferable because it is excellent.

The coating layer consisting of the intermediate layer and the outer layer in the coated iron-based alloy with excellent surface precision of the present invention varies depending on the application, but
20 μm thick, especially 2 to 10 μm thick. If it is wm, it has excellent wear resistance and peeling resistance, so that a significant improvement in life can be achieved. The outer layer in this coating layer is composed of at least one layer. Further, on the surface of the outer layer, carbides of metals of groups 4a, 5a, and 6a of the periodic table,
Nitride, carbonate, nitride, oxide of A, nitride,
At least one of Si carbides, nitrides, mutual solid solutions thereof, diamond, cubic boron nitride, etc.
It is also preferable to laminate the outermost layer of a highly rigid material.

To produce the coated iron alloy (alloy) of the present invention with excellent surface precision, the surface of the substrate is coated with iron and titanium or an iron-titanium alloy by plating or PVD, and then an outer layer is formed by CVD. It is also possible to form an intermediate layer at 800°C to 1100°C by increasing the carbon potential in the atmosphere, and then forming an outer layer by lowering the carbon potential in the same reaction vessel.However, the process can be simplified. The following method is particularly preferred from the viewpoint of stabilization of the coated iron-based alloy.

That is, in the method of manufacturing a coated iron-based alloy with excellent surface precision of the present invention, an iron-based alloy substrate placed in a reaction vessel is maintained at 800°C to 1100°C, and the inside of the reaction vessel is heated with titanium halide. Hydrogen and hydrocarbons and optionally nitrogen,
A method for producing a coated iron-based alloy comprising forming a coating layer on the surface of the substrate by maintaining the substrate in an atmosphere consisting of at least one of ammonia, hydrazine, carbon monoxide, and carbon dioxide, wherein the hydrocarbon/hydrogen gas volume ratio is 17
Titanium carbide, titanium carbonitride, titanium carbonate, carbon an intermediate layer consisting of at least one titanium compound among titanium nitride oxides and an intermetallic compound of iron-titanium; and at least one of titanium carbide, titanium carbonitride, titanium carbonate, titanium carbonitride oxide, and titanium nitride. It is characterized by forming a covering layer consisting of an outer layer of seeds.

In the method of manufacturing a coated iron-based alloy with excellent surface precision of the present invention, the gas volume ratio of hydrocarbon/hydrogen and the volume ratio of titanium element in titanium rogenide/carbon element in hydrocarbon are as follows:
If an intermediate layer consisting of titanium carbide and an intermetallic compound of iron-titanium is to be formed on the surface of the substrate, which has a large influence on the carbon potential in the reaction vessel, the hydrocarbon/hydrogen gas volume ratio should be set to 1710. ~5/10G, an intermetallic compound of titanium carbonitride and iron-titanium, an intermetallic compound of titanium carbonate and iron-titanium, or an intermetallic compound of titanium carbonitride and iron-titanium is formed on the surface of the substrate. When forming a hydrocarbon/hydrogen gas volume ratio of 8/100 to 1
/100 is preferable because the surface precision of the coating layer is particularly excellent. In addition, when forming these intermediate layers on the surface of the substrate, it is recommended to keep the volume ratio of titanium element in titanium halide/carbon element in hydrocarbon to 175 or less, especially to improve the adhesion between the substrate and the intermediate layer and the coating. This is preferable because the surface accuracy of the layer is excellent.

Furthermore, the carbon potential inside the reaction vessel fluctuates depending on the atmospheric gas pressure, especially from 350 tart to 650 tart.
It is preferable to use a reduced pressure state of torr.

(Function) In the coated iron-based alloy with excellent surface precision of the present invention, the intermediate layer plays a mediating role in increasing the adhesion between the base and the outer layer, and also functions to smooth the surface of the outer layer. It is something. In addition, in the method of manufacturing a coated iron-based alloy with excellent surface precision according to the present invention, the atmospheric gas composition ratio in the reaction vessel facilitates control of the carbon potential and has the effect of stably forming an intermediate layer on the surface of the substrate. This is what we do.

(Example) Example 1 After installing a substrate made of a mold made of 5KDII in a reaction vessel, the interior of the reaction vessel was filled with TiC, CH4, and H2 at a volume ratio of Ti/C 2/25, CH4/H2
# 1/25 (7) atmosphere, pressure 600 torr,
The temperature was kept at 1030°C for 30 minutes, and then the volume ratio of Ti
/C 2/25, CH4/)I2# 2/25
A product A of the present invention was obtained by forming a coating layer on the surface of the substrate under the same conditions as described above except for the IHI I ao content during holding.

For comparison, the volume ratio is Ti/C# 17150,
CH4/H2 #3150 atmosphere, pressure 10
A coating layer was formed on the surface of the substrate under the same conditions as above except that the temperature was 0 torr and the holding time was 210 minutes.
I got it. The surfaces of the product A of the present invention and the comparative product A thus obtained were subjected to a lapping process, and an Al2O3 ceramic powder molding process was performed. Table 1 shows the working time required for finishing, the surface dimensional accuracy after finishing, and the life time during powder molding.

Table 1 When the coating layers of the invention product A and the comparative amount A were examined using X&1 diffraction and a scanning microscope, it was found that the coating layer of the invention product A was Fe2
The intermediate layer containing a mixture of Ti, FeTi, and Tic had a thickness of about 1 μm, and the outer layer of TiC had a thickness of about 77 zm. Comparison amount A
The coating layer was a TiC layer of about 81 Lm x&! of Invention Product A. The diffraction results are shown in FIG. Fe in Figure 1
The diffraction line is due to 5KDII of the substrate. Also 1
FIG. 2 shows the structure of the coating layer of the product of the present invention.

Example 2 After installing a substrate made of a punch made of 5KH9 in a reaction vessel, the interior of the reaction vessel was filled with Ti/C# 4/25, C2 in volume ratio using TiC pattern a + C2H6 + H2.
H6/H2#1150 atmosphere, pressure 500
torr.

Hold at a temperature of 1000°C for 30 minutes, and then mix at a volume ratio of 8 and 1.
i/C=4/25, C2H6/H2? /100
A coating layer was formed on the surface of the substrate under the same conditions as described above except that the atmosphere was 150 minutes and the holding time was 150 minutes to obtain product B of the present invention.

For comparison, the volume ratio of Ti/C is 8/25, C2
H6/H2#1/8 atmosphere 7 pressure 10 torr
A comparative amount B was obtained by forming a coating layer on the surface of the substrate under the same conditions as described above except for a holding time of 180 minutes.

When the thus obtained product B of the present invention and comparative amount B were used for cold punching of a 0.5 m + * thick plate made of 5US304, product B of the present invention
The lifespan of the product A was approximately twice as long as that of the comparative amount B. When the WIM of the inventive product B and the comparative amount B were examined in the same manner as in Example 1, the coating layer of the inventive product A was found to be Fe2
The intermediate layer containing Ti and TiC has a thickness of approximately 0.7 μm and T
The outer layer of iC was approximately 4 μm thick. The coating layer of comparative amount B was a Ti 0 layer of about 5 pm.Example 3 A die made of SKH57 was used as a base, and the atmosphere in one reaction vessel was Ti/C=2/25, CHa/H2/L/ 2
5, the holding time was 10 minutes, and then the atmosphere in the reaction vessel was Ti/C# 2/25, CHa/H2# 2/2.
5 Te, invention product A of Example 1 except for holding time 80 minutes
A coating layer was formed on the surface of the substrate under the same conditions as described above to obtain product C of the present invention.

For comparison, the comparative amount A of Example 1 was used except for the retention time of 90 minutes.
A comparative amount C was obtained by forming a coating layer on the surface of the substrate under the same conditions as described above.

After finishing (lapping) the product C of the present invention and the comparative product C, they were used for drawing of permalloy tape recorder parts. Table 2 shows the working time required for the finishing process, the surface dimensional accuracy after finishing, and the number of pieces processed until the life of the drawing process.

Table 2 The coating layers of the invention product C and the comparative amount C were examined in the same manner as in Example 1.1 The coating layer of the invention product C was Fe2T.
i, FeTi, and TiCc7) mixed intermediate layer is approximately 0.5
pm thickness and the outer layer of TiC was approximately 2.5 μm. The coating layer of comparative amount C was about 31 m of Ti0 layer.

Example 4 After forming a coating layer using a seaming roll made of SUS44OC as a base under the same conditions as the invention product C of Example 3, a coating layer was formed using TiC material a, N2, and H2 in the same manner as before. Atmosphere: 1000'C, 450torr, 6
The outermost layer of TiN was formed by holding for 0 minutes to obtain a product of the present invention.

For comparison, a coating layer was formed on the same substrate under the same conditions as the comparative amount C of Example 3, and then a TEN coating layer was further formed under the same conditions as described above to obtain a comparative sample.

After finishing the products of the present invention and comparison scales thus obtained, they were used for seaming the can bodies and can lids together. Table 3 shows the working time required for the finishing process and the number of cans sealed with a chisel.

Table 3: The coating layer of the product of the present invention and the comparison weight were examined in the same manner as in Example 1, and the coating layer of the product of the present invention was found to be
In addition to the same intermediate layer and outer layer, a TiN outer layer of about 3 μm was formed. The comparative coating layer is approximately 3 m
A TiO layer of about 3 pm and a TiN layer of about 3 pm were formed.

Example 5 Using a mold made of SKD61 as a base, using TiC pattern a, CH4, and H2, holding time was 20 minutes in the atmosphere in the first stage, holding time was 40 minutes in the atmosphere in the second stage, Other conditions were the same as those for product A of the present invention in Example 1! ! After forming two layers, 20va
i%N2 and 80voi% (T i 0 sentence 4, CH4
, H2) at a volume ratio of Ti/C# 1/10.
, CH4/H2? /+00 atmosphere, pressure 450
torr, a temperature of 1000°C, and a holding time of 30 minutes, and then TiC, NHa, and H? under the same atmosphere as before, at a pressure of 400 tarr.

A product E of the present invention was obtained by processing at a temperature of 800° C. and a holding time of 30 minutes.

For comparison, a similar substrate was treated under the same conditions under which comparative amount A of Example 1 was prepared, except for a holding time of 60 minutes, and then a pressure of 4 was applied using TiCfJ,a, NH4, and H2.
00 tarr, temperature of 800° C., and holding time of 30 minutes to obtain product E of the present invention.

The product E of the present invention thus obtained and the comparative amount E were subjected to finishing processing and then used for injection molding of Plasti-7.

At this time, we investigated the working time required for finishing, the surface dimensional accuracy after finishing, the number of molded pieces until the service life during injection molding, and the surface condition of the workpiece after injection molding, and the results are shown in Table 4. It was shown to.

Below, the coating layers of the present invention product E and the comparative amount E were examined in the same manner as in Example 1, and it was found that the coating layer of the present invention product E was Fe;
The intermediate layer containing Ti, FeTi, and Tie is approximately 0.8B.
A Tic outer layer with a thickness of about 0.8 μm, a Ti(C,N) outer layer with a thickness of about 1.0 μm, and an outer layer of TiN with a thickness of about 1.0 μm were formed. . The comparative amount E of the coating layer is approximately 2.5 μm P
m thick TiN layer was formed.

(Effects of the Invention) The coated iron-based alloy of the present invention has a smooth surface compared to conventional coated iron-based alloys, so when used after mirror finishing, the coated iron-based alloy has a surface precision of about 40% It is possible to shorten the machining time by ~10 times, and the machining surface accuracy at that time is approximately 2.
The effect is that a product that is 5 to 3 times better can be obtained. In addition, the coated iron-based alloy of the present invention has excellent surface precision, and the intermediate layer improves the adhesion between the base and the coating layer, which improves the service life by approximately 1.4 to 25 times. There is an effect. Furthermore, the surface roughness of workpieces machined using the coated iron-based alloy of the present invention is superior to that of workpieces machined using conventional coated iron-based alloys.

In addition to these, if an outermost coating layer, such as titanium nitride, aluminum oxide, diamond, or cubic boron nitride, which has excellent adhesion to the outer layer, is formed on the surface of the outer layer of the coated iron-based alloy of the present invention, The coated iron-based alloy of the present invention is
Furthermore, it is industrially useful because it can extend its lifespan and expand its uses.

[Brief explanation of drawings]

FIG. 1 shows the results of X-ray diffraction of the intermediate layer of product A of the present invention obtained in Example 1. FIG. 2 shows the structure of the coating layer of the product A of the present invention obtained in Example 1. In FIG. 2, 1 represents the outer layer, 2 represents the intermediate layer, and 3 represents the base body. Patent Applicant: Toshiba Tungaloy Co., Ltd. Fuji Dice Co., Ltd. 1 Figure 2 Figure 2 Supplement 1 EJF (method) 1 , -1+ indications Patent Application No. 105733/1982 2 Name of the invention Coating with excellent surface precision Iron-based alloys and their manufacturing method Persons/If ('l) Relationship with patent applicant 1-7 Tsukagoe, Yozaki City, Kanagawa Prefecture July 28, 1988 (shipment date) 5. Supplement! Subject 4 of E, Brief explanation of drawings 6, Contents of amendment (1) Page 21 of the specification, line 3 of the brief explanation of drawings column ~
The "structure of the covering layer" in the fourth line is corrected to "crystal structure of the covering layer". that's all

Claims (4)

[Claims] (1) A coated iron base formed by interposing an intermediate layer between a base of an iron-based alloy and an outer layer made of at least one of titanium carbide, titanium carbonitride, titanium carbonate, titanium carbonitride, and titanium nitride. In the alloy, the intermediate layer is made of at least one titanium compound selected from titanium carbide, titanium carbonitride, titanium carbonate, and titanium carbonitoxide, and iron-titanium, and an intermetallic compound. Excellent coated iron-based alloy. (2) The coated iron-based alloy with excellent surface precision according to claim 1, wherein the intermediate layer has an average thickness of 1 μm or less. (3) The above intermetallic compound is FeTi and/or Fe_
The coated iron-based alloy with excellent surface precision according to claim 1, characterized in that it is 2Ti. (4) The iron-based alloy substrate installed in the reaction vessel
°C to 1100 °C, and the inside of the reaction vessel is made into an atmosphere consisting of titanium halide, hydrogen, hydrocarbons, and, if necessary, at least one of nitrogen, ammonia, hydrazine, carbon monoxide, and carbon dioxide. In the method for producing a coated iron-based alloy in which the hydrocarbon/hydrogen gas volume ratio is 1/10 or less, and the titanium element in the titanium halide/ At least one titanium compound selected from titanium carbide, titanium carbonitride, titanium carbonate, and titanium carbonitoxide is added to the surface of the substrate in an atmosphere in which the volume ratio of carbon element in the hydrocarbon is 1/4 or less. and an intermetallic compound of iron-titanium, and an outer layer of at least one of titanium carbide, titanium carbonate, titanium carbonate, titanium carbonitride, and titanium nitride. A method for manufacturing a coated iron-based alloy with excellent surface precision.