JPH0771742B2 - Joining method of titanium carbide sintered alloy and stainless steel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining technique between a titanium carbide sintered alloy and stainless steel, and more specifically, it requires wear resistance, and the stainless steel portion requires post-joining working and welding. The present invention relates to a joining method of a titanium carbide sintered alloy and stainless steel suitable for joining a die plate tile part used in a part such as a plastic pelletizer.

[0002]

2. Description of the Related Art Conventionally, when a member requiring abrasion resistance is manufactured, as shown in FIG. 3, a material 51 having abrasion resistance is applied only to a portion requiring abrasion resistance. The inexpensive ordinary material 52 is used for the other parts. In this case, a titanium carbide sintered alloy (hereinafter referred to as TiC sintered alloy) is used as the wear resistant material, and carbon steel is used as the normal material.

In order to manufacture a member requiring abrasion resistance by this, it is necessary to join TiC sintered alloy and steel, and as a method therefor, the inventors of the present invention previously invented the method. There is a joining method as described in Japanese Patent No. 5072.

[0004]

As described above, even in the above-mentioned conventional technique, it was possible to join the TiC sintered alloy and the steel to manufacture a member having abrasion resistance at a low cost. However, according to the method described in the above publication, a TiC sintered alloy whose matrix is a precipitation hardening type material,
When martensitic stainless steel is joined, as described below, the martensitic stainless steel after joining becomes too hard and cracks, or the hardness of the TiC sintered alloy is too low, resulting in wear resistance. There were various problems such as poor quality.

The present invention has been made in order to solve the above problems of the prior art, and is TiC having wear resistance.
An object of the present invention is to provide a joining technique capable of producing a joined body of a sintered alloy and a stainless steel which has sufficient ductility that does not cause cracks or the like during welding and is easy to process after joining.

[0006]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above-mentioned problems in joining TiC sintered alloy and stainless steel by the conventional method, and as a result, they are described in the claims. It was confirmed that the above object was achieved by the joining method of the TiC sintered alloy and the stainless steel. That is, when joining a TiC sintered alloy whose matrix is a precipitation hardening type material and a martensitic stainless steel, a Ni-containing insert material is used, the insert material is heated and melted to join the two, and then the solid of the insert material is fixed. Cool at a rate of 5 ° C / min or less to a temperature 10 ° C or more and 70 ° C or less lower than the phase line temperature, then 8 ° C / mi
cooling to 650 ° C or higher and 750 ° C or lower at a speed of n or higher,
This is a method for joining a TiC sintered alloy and martensitic stainless steel in which the temperature is maintained for 120 minutes or more and 360 minutes or less and then cooled. Hereinafter, the operation and the like of the present invention will be described based on Examples.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining a joining method of a TiC sintered alloy and stainless steel according to the present invention, FIG. 1 is a diagram showing a relationship between time and temperature in each joining step, and FIG. 2 is a joining member. It is a figure which shows the structure of. 1 and 2, 1 is a bonding temperature, 2 is an A part, 3 is a B part, 4 is a C part, 5 is a D part, 6 is an E part, 7 is a bonding region, 8 is a temperature holding region, and 11 is TiC. A sintered alloy, 12 is an insert material, and 13 is stainless steel.

According to the present invention, when joining a TiC sintered alloy member whose matrix is a precipitation hardening material and a martensitic stainless steel member, an Ni-containing insert material is used for heating and melting, and then brazing. It is possible to obtain a bonded body having wear resistance by cooling at the cooling rate described in the claims, holding for a predetermined time, and further cooling.

Here, the use of Ni-based insert materials in joining TiC sintered alloy members and steel is disclosed in Japanese Unexamined Patent Publication (Kokai) No.
It is already known in the joining method by the inventors of the present application described in Japanese Patent Publication No. 5072.

10 after the solidus temperature of the insert material after joining
Cooling at a rate of 5 ° C / min or less to a low temperature of ℃ or more and 70 ° C or less is to prevent cracking of the joint and excessive residual stress due to rapid cooling. Occur.

After that, from 650 ° C to 750 ° C, 8 ° C
The cooling at a speed of not less than / min is to secure the hardness of the TiC sintered alloy, and at a speed of less than this, the T after the aging treatment is performed.
The hardness of the iC sintered alloy is insufficient, and eventually the original wear resistance of the TiC sintered alloy cannot be obtained.

The holding time after cooling is 120 min or more 36
The reason for setting it to 0 min or less is to prevent excessive hardening of the martensitic stainless steel and to secure the hardness of the TiC sintered alloy. If the holding time is less than 120 min, the martensitic stainless steel is excessively hardened, and if the vicinity of the joint is welded after joining, this portion becomes hard and brittle, and cracks occur or machining becomes extremely difficult, which is not preferable. . On the other hand, if the holding time exceeds 360 min, the hardness of the TiC sintered alloy after the aging treatment becomes insufficient, which eventually causes a problem that the original wear resistance performance of the TiC sintered alloy cannot be obtained.

The inventors of the present application actually conducted a joining experiment between the TiC sintered alloy and the stainless steel based on the joining method described above. The results of the experiment will be described below.

(1) First Experimental Results A TiC sintered alloy (Ti: 5 mm × diameter) containing 32% by weight of TiC and a matrix component containing Cr, Co, Ni, Mo, Al, Ti, Cu in a Fe base. 300 mm) and martensitic stainless steel (SUS403: thickness 50 m)
m × diameter 300 mm) and the Ni-based C shown in FIG.
Insert materials containing r, B, Si and Fe (solidus temperature 970 ° C., liquidus temperature 1000 ° C.) were sandwiched and heated to 1050 ° C. in a vacuum furnace to bond the two. Then cool down
The holding pattern was changed and it cooled to room temperature. The respective conditions at that time are as shown in Table 1. After that, all the bonded bodies were subjected to an aging treatment at 480 ° C. for 60 minutes.

The hardness of the obtained bonded body was measured with a Rockwell hardness meter. As for the result of hardness, two types of scales are available for Rockwell hardness, which makes it difficult to understand the result. Therefore, the Rockwell hardness is shown here in terms of Vickers hardness. We also investigated the weldability and wear resistance of some test pieces. The hardness of the TiC sintered alloy before joining is Hv46.
0, the hardness of martensitic stainless steel is Hv165
Met.

[0016]

[Table 1]

In Table 1, Samples 13 and 14 are the case where they were cooled without being maintained at a constant temperature during the process. Sample 13 is 9
It was cooled to 50 ° C and then gas cooled.
The hardness of the martensitic stainless steel was high, and when the stainless steel part of this sample was electron beam welded, cracks occurred in the heat affected zone. Sample 14 was cooled by furnace cooling, but the TiC sintered alloy had a slow cooling rate, and its solid solution was insufficient to provide sufficient hardness, and the hardness of martensitic stainless steel was too high. .

Samples 1 to 7 are experiments conducted by changing the holding temperature D. If the holding temperature is too high, the hardness of the martensitic stainless steel is too high, and if the holding temperature is too low, a TiC sintered alloy is produced. Hardness is too low. Regarding sample 4, even if the stainless steel part was electron beam welded, no cracks and the like were generated and machining was easy. Moreover, as a result of performing a pellet cutting test after processing this joined body into a pelletizer die plate, sufficient wear resistance was obtained in the TiC sintered alloy portion. A pellet cutting test was also performed on the joined body of Sample 7, but the wear resistance was insufficient because the hardness of the TiC sintered alloy was not sufficient.

Samples 8 to 12 are experiments conducted by changing the holding time E. When the holding time is too short, the hardness of the martensitic stainless steel is too high, and when the holding time is too long, T is given.
The hardness of the iC sintered alloy was too low.

(2) Second Experimental Results TiC containing 30% by weight of TiC and the matrix component containing Ni, Co, Mo, Al, Ti and Cu in the Fe group.
Sintered alloy (thickness 5 mm x length 100 mm x width 100 m
m) and martensitic stainless steel (SUS40
3: Thickness 20 mm × length 100 mm × width 100 mm), as shown in FIG. 2, insert material containing Ni and B and Si (solidus temperature 980 ° C., liquidus temperature 1040)
(° C), and the two were joined by heating to 1100 ° C in a vacuum furnace. After that, the cooling / holding pattern was changed to cool to room temperature. Table 2 shows each condition. After that, all the bonded bodies were subjected to an aging treatment at a temperature of 480 ° C. for 360 minutes.

The hardness of the obtained bonded body was measured with a Rockwell hardness meter. Regarding the result of hardness, first
Rockwell hardness was converted to Vickers hardness and shown in the same manner as in the experiment. Further, some of the experimental pieces were microscopically observed. The hardness of the TiC sintered alloy before joining is Hv5.
20, the hardness of martensitic stainless steel is Hv22
It was 0.

[0022]

[Table 2]

In Table 2, Samples 21 to 26 are obtained by changing the cooling rate of the part A. It can be seen that if the cooling rate is too fast, cracks occur at the joint. Samples 27 to 29 have different cooling rates for the C part. It can be seen that the hardness of the TiC sintered alloy becomes low when the cooling rate is too slow.

[0024]

As described above, according to the present invention, as described in detail in the above embodiment, by joining the TiC sintered alloy and the martensitic stainless steel, the TiC sintered alloy provides sufficient wear resistance. It is possible to provide a technique capable of producing a joined body having sufficient ductility and having sufficient ductility with martensitic stainless steel.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between time and temperature in each joining process in a joining method according to the present invention.

FIG. 2 is a diagram showing a configuration of a joining member in a joining method according to the present invention.

FIG. 3 is a diagram showing a configuration of a joining member in a conventional technique.

[Explanation of symbols]

 1 Joining Temperature 2 A Part 3 B Part 4 C Part 5 D Part 6 E Part 7 Bonding Area 8 Temperature Holding Area 11 TiC Sintered Alloy 12 Insert Material 13 Stainless Steel 51 Material with Wear Resistance 52 Normal Material

Claims (1)

[Claims] 1. When joining a titanium carbide sintered alloy whose matrix is a precipitation hardening type material and a martensitic stainless steel, a Ni-containing insert material is used, and the insert material is heated and melted to join the two. After that, it is cooled at a rate of 5 ° C / min or less to a temperature 10 ° C or more and 70 ° C or less lower than the solidus temperature of the insert material, and then 8 ° C / min.
A titanium carbide sintered alloy and a martensitic stainless steel, which are characterized by cooling to a temperature of 650 ° C. or higher and 750 ° C. or lower at a speed of min or more, holding at that temperature for a time of 120 min or more and 360 min or less, and then cooling. How to join.