JPS59209473A - Production of bonding member for sintered hard alloy and sintered steel - Google Patents

Abstract

PURPOSE:To prevent peeling between a sintered hard alloy and a steel on account of a heat treatment, etc. in the stage of brazing the two members by using a molding of raw material powder for a sintered steel for the steel member, bringing powder of a specifically composed brazing material into contact with said molding and the sintered hard alloy and brazing the two members. CONSTITUTION:A sintered hard alloy is used for the sliding part alone and other parts are constituted of an inexpensive steel material to reduce the cost of production in the stage of producing a wear-resistant sliding part. A brazing material C of an alloy consisting of 35-45wt% Cu, 40-45wt% Ni, and 15-20wt% Mn is disposed in contact with both of a sintered hard alloy part A and a steel part B and the two parts are brazed. A molding of the raw material powder of the sintered steel is used for the part B and is heated in a reducing gaseous atmosphere of cracked gaseous ammonia, etc. Sintering of the powder molding of the sintered steel and brazing by the brazing material are simultaneously accomplished. An infiltrating material consisting of the molding of the alloy element powder may be used to increase the strength of the sintered steel and may be infiltrated into the sintered steel.

Description

[Detailed Description of the Invention] [Prior Art] The present invention provides a method for manufacturing wear-resistant sliding parts such as dies, punches, seal rings, rocker arm butt materials, and polishing discs used for punching precision parts such as mold materials. Regarding manufacturing. For such parts, a composite material is used in which cemented carbide is used only in the necessary parts, and steel is used as a supporting material for the cemented carbide in other parts, and both parts are joined by brazing. When this composite material is brazed over a large area, such as for a mold, the difference in thermal expansion between the cemented carbide and steel causes tensile stress to be generated between the cemented carbide and the steel during cooling, causing the brazing to come off.
There were many problems such as cracks forming in the cemented carbide.

[Purpose of the invention]

The present invention is a cemented carbide that does not separate the cemented carbide from the steel or cause cracks in the cemented carbide even if the net portion brazed to the cemented carbide is subjected to processing treatments such as heat treatment and wire cutting. It is an object of the present invention to provide a method for obtaining a bonded member of alloy and steel.

[Disclosure of the invention]

In order to achieve this object, the present invention brings a cemented carbide member and a sintered steel raw powder molded body into contact with each other, places a brazing filler metal in contact with both, and heats it in a reducing atmosphere to form a wafer-formed steel. The raw material powder is sintered steel, and at the same time, the sintered 2iffl and the cemented carbide member are bonded using the brazing filler metal.

In the present invention, when a raw material powder molded body of sintered steel is sintered,
Ou 33 to 1% by weight, N1, which has the property of reacting with iron in the raw material, alloying, and at the same time raising the melting point and solidifying.
A wax having a composition of 0 to 1 l-5% by weight of Mn/3 to 0% by weight of Mn is used.

Brazing sintered steel or sintered steel and materials other than sintered steel +1
As a brazing material for sintering, the brazing material is absorbed into the pores of the sintered steel when the brazing material gathers and melts, making it useless as a bonding material. The present invention solves these problems by using a wax having the above composition.

Generally, one of the properties of metals is that when metals with different melting points are alloyed, the melting point of the alloy will be different from the melting point of each original metal, and if it shows a value between the two melting points. There are many.

The wax of the present invention is an application of this phenomenon.

/ is the melting point of the filler metal close to the sintering temperature of sintered copper (
However, by adjusting the temperature to a temperature lower than the sintering temperature, sintering and bonding of the sintered steel can be performed simultaneously.

The reason is that when this alloy is considered as a metal, when it melts and causes an alloy reaction with Fe in the sintered steel, the melting point of Fe is higher, so the melting point of the filler metal rises and solidifies. Diffusion of sintered steel into the pores is suppressed.

In other words, the composition of the brazing filler metal is Ou 33~Geta 5%, Ni
70~data weight%, Mn/s~, 20% by weight. Firstly, if the composition is in this range, the melting point of the brazing filler metal will be between 7000~/100'C, and the sintering temperature will be lower. This is due to the fact that the temperature can be set directly below.

In addition, since Cu, Ni, and Mn each exhibit a simple alloying reaction with Fe in a high temperature range, they react smoothly with the wax which is their alloy, and the melting point rises and solidification occurs stably.

By satisfying these conditions, sintering of sintered steel and bonding with cemented carbide become possible.

If the composition of the wax is outside the range specified in section 2, an appropriate melting point will not be obtained and the purpose will not be achieved.

to form an alloy layer. Therefore, since an alloy layer is formed in both sintered steel and cemented carbide, and since the sintered steel, which is the support material for cemented carbide, is porous, thermal expansion differences between the cemented carbide and the cemented carbide occur at the joint surface. It acts as a stress buffer and also helps prevent peeling and cracking of cemented carbide during bonding and heat treatment processes.

Since the material produced by the method of the present invention is made by bonding sintered steel to a cemented carbide member, it can be used as is or machined depending on the usage conditions. However, if the sintered steel used as a support material for the cemented carbide requires higher mechanical strength, the mechanical strength can be improved by subjecting it to heat treatment such as quenching and tempering.

In order to improve the mechanical strength of sintered steel, alloying element powder may be added to the raw material powder of sintered steel, and the raw material iron powder may be used as an alloy. Further, an alloying element powder molded body for improving the mechanical strength of the sintered steel may be superimposed on the raw material powder molded body of the sintered steel and infiltrated at the same time as sintering.

Example/ Particle size/μm we powder go wt%, particle size/μm c.

Powder, outer diameter of 20% by weight composition 1. Qmm, inner diameter 3Qm
m, thickness/Q mu cemented carbide member A, o0g weight%
Iron powder mixed with carbon fine powder of 1. A sintered steel raw material powder molded body B compacted to a size of Qmm, inner diameter Qmm, and thickness 3Qmm, and C! u'70 weight i%, Ni'1
A brazing filler metal powder having a composition of 2% by weight and 7g% by weight of Mn was prepared with an outer diameter of 39 mm, an inner diameter of 011 Lffl, and a thickness of 2.
A brazing filler metal C was made by embossment molding, and as shown in FIG. 1, C was fitted inside A, and this was superimposed on B in a concentric circle. This is heated in ammonia decomposition gas at 0C for 2 hours to sinter the sintered steel raw powder compact to make sintered steel, and at the same time apply wax to the interface between the sintered steel and the cemented carbide. A bonding member which was impregnated and made into one piece was obtained.

The bonding strength between the cemented carbide member and sintered steel of this bonding member is
:13 kg/4 nm. When the inner and outer circumferences of this coupling member were polished and used as a seal ring for a pump bearing, it exhibited good wear resistance and a lifespan 70 times longer than conventional iron-based seal rings.

Example λ 100 mm long with composition of WO39% by weight and 0020% by weight
.

Rectangular plate-shaped cemented carbide member A with width gQmm and thickness λmm
A sintered steel raw powder powder molded body B is made by compacting iron powder containing fine carbon powder of o, g wt % into a rectangular parallelepiped measuring 100 mm long and 17 mm thick (7 ffll11), O 3 g wt %, Ni A brazing filler metal powder having a composition of 3% by weight and 9% by weight of Mn was prepared into a piece with a width of IO"m', a length of 100mm, and a thickness of 3mm.
Two pieces of brazing filler metal were made by pressing and molding into a long and narrow shape. As shown in Figure 2, stack A on top of B so that both ends of the upper surface of B remain evenly,
I overlapped the O so that it just covered the remaining part of the top surface.

This was heated to //30C for 7 hours in ammonia decomposition gas. After heating, the brazing filler metal penetrated into the joint surface between the cemented carbide member and the sintered steel, and the cemented carbide member and the sintered steel were completely bonded.

The hardness of the sintered steel was approximately HRBI>0 after heating and tempering this bonding member for 7 hours with GLLO'C and 3 hours with /gOC/. The heat treatment did not cause peeling or cracking of the cemented carbide.

This member was cut out by wire cutting, a punch for punching a silicon steel plate was manufactured, and a punching test was conducted, which showed that the punch had a lifespan approximately 70 times longer than that of die steel. In addition, the punched products had fewer cracks and were highly accurate.

Example 3 These elemental powders were mixed with a composition of Cu-3 heavy bale % - weight % Fe and pressed to make a die infiltration mold having a length and width of 100 mm and a thickness of 79 mm. On top of this, the sintered steel raw material powder molded body B of Example 1 is superimposed, and on top of this, the cemented carbide member A and solder C of Example λ are placed as shown in FIG. in ammonia decomposition gas //Otsu0
The mixture was heated at C for 2 hours. The sintered cemented carbide member on the sintered steel was completely bonded by infiltration of the brazing filler metal, and the bonding strength was sufficient.

This joining member was heated at g θC for 7 hours and then quenched.
Tempering was performed by heating at 0C for 7.3 hours. The hardness of this sintered steel was on the order of HRO'IO, and there was no peeling or cracking of the cemented carbide due to heat treatment.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a manufacturing method of Example 1, FIG. 2 is a sectional view of Example 2, and FIG. 3 is a sectional view showing a manufacturing method of Example 3. A: Cemented carbide member, B: Sintered steel raw material powder compact, C
Brazing filler metal, D...embossed infiltration material. 4 Figure 1 Figure B Figure 2 Figure 3

Claims (4)

[Claims] (1) A braze is placed in contact with both the cemented carbide member and the raw material powder molded body of sintered steel, and this is heated in a reducing atmosphere to sinter the raw material powder molded body to produce sintered steel. A method for producing a joining member of cemented carbide and sintered steel, characterized by simultaneously joining the cemented carbide member and sintered steel. (2) A method for manufacturing a joining member of cemented carbide and sintered steel according to claim (1), wherein the brazing material is a molded body of brazing material powder. (3) The brazing filler metal composition is Ou: 3. ! ;~'l!
; Weight %, Ni Nige 0~/l Shio weight %, Mn: 75
A method for producing a bonding member of cemented carbide and sintered steel according to claim (1) or (2), characterized in that the amount of unavoidable impurities is 20% by weight. (4) A brazing material was placed in contact with both the cemented carbide member and the sintered steel main raw material powder molded body, and a molded body of an infiltration material for the sintered steel was further placed in contact with the molded body. Cemented carbide and sintered steel, characterized in that the cemented carbide member and the sintered steel are sintered by heating in a reducing atmosphere and infiltrating the molded body with an infiltrating material. A method of manufacturing a joining member with steel.