JPS60170585A - Joining member for sintered hard alloy and steel and its production - Google Patents

Abstract

PURPOSE:To obtain a joining member for a sintered hard alloy and steel by inserting a metallic filler having a specific thickness between the sintered alloy and the steel and joining the alloy and steel by a high energy beam under pressure. CONSTITUTION:A steel material 7 and a sintered hard alloy 8 are set into a vacuum chamber 6 and a Monel filler sized >=0.5mm. and <=2mm. is inserted between the material 7 and the alloy 8. The material 7 is fixed by a rotating jig 9 and the alloy 8 is press-welded thereto by a pressing jig 10. The jig 9 is rotated to press the steel 7 and the alloy 8 under the force under which both materials rotate simultaneously without slipping. The inside of the chamber 6 is evacuated to a vacuum and an electron beam is generated from an electron gun 11 and the beam is applied to the joint surfaces of the alloy 8 and the steel 7 on the side nearer the sintered hard metal alloy side by a prescribed distance from said surfaces thereby preheating the alloy 8. Welding is further executed by penetrating the beam into the Monel filler.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a cold forging punch, a hot forging punch, a mold, etc. in which cemented carbide and steel are joined.

(Technical background) Generally, cemented carbide is joined by brazing using A20 or the like. However, since forging punches and the like are used under high loads of ψ1h between 200 and 300 mm, brazing may cause the part to come off, and it has not been put to practical use. Because the metal on both sides of the joint is heated, the temperature of the steel rises, causing the copper to become dull and deform under high pressure loads.Secondly, there is a difference in thermal expansion coefficient between steel and cemented carbide, so residual Stress remains and becomes a source of cracks during repeated impact. Thirdly, due to the low compressive strength of the raw material itself, there were problems such as deformation of the raw material when an impact was applied, so it is difficult to use cemented carbide in this type of field. It had not been done. Recently, a joining method using high-energy beams has been developed and is being put into practical use, but it has not yet been put into practical use in the field of forging punches, which require a large number of repetitions.

The reason is that cemented carbide is susceptible to thermal shock, and steel undergoes transformation when heated to high temperatures. When joining with a high-energy beam, cracks are likely to occur in cemented carbide due to thermal shock, and in steel due to a decrease in tensile strength due to transformation.

(Disclosure of Occurrence) The present invention was obtained as a result of intensive investigation to solve these problems. The gist of it is: What is the difference between cemented carbide and steel? j” 0.5 mrn or more 2mm
The present invention provides a cemented carbide and steel joining member in which the following diffusion layer is formed for at least 1j times. The second invention is a method for joining cemented carbide and steel, with a thickness of 0.5 or more wires between the two.
The present invention provides a method for manufacturing a joining member of cemented carbide and a chisel by inserting a metal filler of +n+n or less, applying pressure to the insertion surface, and applying a high-energy beam to the cemented carbide side. It is desirable that the metal filler has a melting point of 1000° C. or higher; below that, mechanical strength such as tensile strength is usually low. Further, as the high-energy beam, an electron beam or a laser beam is generally used and can be easily used. FIG. 1 shows the distribution of Ni when the cemented carbide 1 and the metal foil 2 are bonded using a Ni metal foil 3 with a thickness of 0.9 mm. Part 4 is Ni to the cemented carbide side.
In this example, the diffusion layer was about IOμ, and the diffusion layer toward the body side was about 20μ. When Ni was used as the metal filler, no phenomena such as decarburization were observed on the cemented carbide side. Another feature of the invention is that a metal filler of 05-2 mm is inserted between the cemented carbide and the steel, the cemented carbide is directly heated with a high-energy beam, and at the same time the cemented carbide and the steel are pressed together. In particular, J: is a bonding method characterized by diffusion bonding a metal filler into cemented carbide and steel.

If the metal filler exceeds two lines, the metal filler will be compressed and deformed under the high load during use, and will not be able to withstand the forging pressure. The thickness of the filler is preferably 2 m7n or less. 0.5mm
If it is below, the thickness of the filler will be smaller than the diameter of the high-energy beam, and the steel portion will melt. Melted chair or die steel has a reduced fatigue strength, so its life is short when used under high loads such as forging.

Generally, the minimum high-energy beam diameter is 0.3 mm, and the width of the molten bead is 1 to 1.5 mm. Therefore, in order to join without changing the structure of the cemented carbide near the joint, the filler thickness must be 0.5 to 2. A range of Oynm is desirable.

It is desirable to select an appropriate filler thickness in accordance with the beam energy corresponding to the welding depth.

The beam diameter of the high-energy beam is adjusted according to the filler thickness and can heat only the narrow area near the joint, so deformation and transformation of the steel part can be minimized. The filler used in the present invention has a melting point of 0
00°C or higher is better. That is, as a method for joining cemented carbide with excellent impact resistance and copper, it is desirable to use a material with a high melting point and high tensile strength. For example, pure Ni, a material containing Ni and B 1Si, Mn, Mg, etc. can be used, and pure Co or Co.

Many alloys such as Ni can be used. The role of this type of filler is that when Ni or Ni alloys such as Inconel and Monel are used, the solid solubility of carbon is small, so the solid solute carbon on the cemented carbide side and the bonded carbon diffuse into the shell side. You can also prevent it from happening. Separately, multiple 141. It is also possible to use fillers of different quality. For example, by using two fillers with different melting points, it is also possible to obtain a thin alloy with a bonding layer. Furthermore, as mentioned above, thermal history tends to remain in the joints, and cemented carbide, filler, and steel can deteriorate due to thermal stress caused by thermal distortion and temperature rise to near the melting point. be. For this purpose, for example, it is possible to perform a heat treatment process such as hardening in oil, annealing, and tempering by heat treatment after bonding.

In some cases, such as in the case of electron beam welding, it is also possible to control the cooling rate of the joint by introducing a suitable gas into the vessel. Conventional jointing using the brazing method has the disadvantages that the strength of the brazing material itself is low, the heating area is wide, and the transformation range of the steel is wide.

Also, conventional welding methods have similar problems. That is, since the heated area during bonding was extremely wide, the deteriorated layer was wide and did not return to its original state even after heat treatment after bonding. In order to solve this problem, the present invention has a thin thermally altered layer and is easy to recover.

Example Welding of φ20×20 cemented carbide was performed on a φ20×I50 5KD61 preparation. In FIG. 2, a preparation 7 and a cemented carbide 8 were set inside a vacuum chamber 6, and a 1.5 mm thick monel filler was inserted between the preparation and the cemented carbide. The preparation was fixed with a rotating jig 9, and the cemented carbide was pressed with a pressurizing jig 10. By rotating the rotating jig 9, the sardine and the cemented carbide were pressurized with the force of simultaneous rotation without slipping.

Vacuum the chamber to 10-+4 Torr,
An electron beam was generated from an electron gun, and the beam was applied to the cemented carbide side 2 mm from the contact surface of the cemented carbide and copper to preheat the cemented carbide. Furthermore, the electron beam conditions are I 50 kv15mA.
, the beam was introduced into the Monel filler at a heating rate of 100 mm/'n, and welding was performed.

The punch was forged to 545C (300 Kg/cn)
When used for this purpose, the lifespan was 15 times that of die steel pliers.

[Brief explanation of the drawing]

FIG. 1 shows a sectional view of a joining member obtained by the present invention. Figure 2 is a schematic diagram of the electron beam welding equipment.
2 copper, 3 metal filler, 4 diffusion layer, 5...diffusion layer,
6 Vacuum chamber, 10 Pressure jig, 11...Electron gun.

Claims (4)

[Claims] (1) When joining cemented carbide and steel, there is no thickness between the two.
．． A cemented carbide and steel bonding member comprising one or more diffusion layers with a thickness of 5 mm or more in the order of "-2" or less. (2) When joining cemented carbide and steel, there is no thickness between the two.
．． A method for producing a joining member of cemented carbide and steel, which comprises inserting a metal filler of 5 or more and 2 or less, and joining with a high-energy beam while applying pressure to the insertion surface. (3) The method for manufacturing a joining member of cemented carbide and steel according to claim (2), wherein the metal filler has a melting point of 100° C. or higher. (4) Claim (2) characterized in that the high-energy beam is an electron beam or a laser beam.
A method for manufacturing a bonded member of cemented carbide and steel as described in Section 1.