JPS58168486A - Production of blanking punch - Google Patents

Abstract

PURPOSE:To obtain a blanking punch for cold working having excellent toughness,abrasion resistance, etc., by applying a beam having a blurred focus to the joint surface of a high-C steel material and a sintered alloy then irradiating the focused beam to the welding surface. CONSTITUTION:A high-energy beam having a blurred focus is irradiated to a steel material 2 contg. >=0.5% C and a sintered alloy 1 side within the <=2mm. range from the joint face 3 in tight contact with the alloy 1 while the materials to be welded are rotated, in welding of said material 2 and the alloy 1. The energy required for obtaining welding depth is irradiated to the joint surface by throttling the beam diameter in the welding stage. The blanking punch having excellent strength, toughness, resistance 20 repeated fatigue failure, etc. is obtained without generation of any crack in the alloy 1 of the joint face 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the manufacture of a punch for cold working.

Punches used in cold working have traditionally been required to have high impact strength and wear resistance. For punches made of steel, increasing the hardness of the steel reduces toughness and may cause breakage.

On the other hand, when using a cemented carbide that exhibits high wear resistance, if the amount of CO in the WC-CO alloy is increased in order to increase toughness, the wear resistance will decrease and the compressive yield strength will also decrease.

In order to maintain the hardness required for punches, even cemented carbide alloys with relatively high hardness are used. Such alloys have limited toughness and are used only to a limited extent. If steel is used in the parts where toughness is required and cemented carbide is used in the parts where wear resistance is required at the tip, it is thought that it will be used in a fairly wide range of areas, but it is difficult to completely join the carbide and -. It is difficult and has not been put into practical use.

Ag brazing is often used as the most common bonding method for cemented carbide and steel, but Ag brazing has poor fatigue resistance and has problems such as peeling in areas subjected to repeated loads. Further, there are Ou brazing and NI brazing as brazing with a higher melting point, but since these are joined at a temperature of 10OO0c or more, the steel is hardened and the #14β compressive yield strength decreases. Further, friction bonding and the like are considered as methods for joining cemented carbide and steel, but they are insufficient in terms of joint strength.

As a result of research into a manufacturing method for a carbide punch that satisfies performance requirements in terms of toughness and wear resistance, the present inventors found that a method for completely joining the cemented carbide and steel by melting only the joining surfaces was found to have improved strength and toughness.
I found out that it is best for repetitive fatigue.

The method of the present invention is a punch manufacturing method characterized by welding a carbide tip to the tip of a punch shown in FIG. 1 using a high-energy beam.

Generally, carbide tips used for punches and the like have problems with wear and seizure at the tip, so a cemented carbide material with high hardness is required. This highly hard cemented carbide material has a drawback in that it tends to generate heat due to the small amount of Co, which is a bonding metal, in the cemented carbide (WC-co). Therefore, when a high-energy beam such as an electron beam or a laser beam is directly applied to the bonding surface, a rapid temperature rise causes thermal explosion to occur in the hardening alloy, causing cracks during bonding.

Therefore, in the past, there have been many cases in which bonding of cemented carbide and steel has been investigated using electron beams, but this has not been put into practical use due to the problem that the alloy cracks due to the heat beam.

As a result of research into welding methods for cemented carbide and steel, the present inventors discovered that steel requires high compressive strength like a punch.

For example, carbon steels such as 8KH, SKD, and 80M materials with O, S%C or more, and cemented carbide that requires wear resistance (carbon content 5%
We have discovered a method for bonding with the above-mentioned chips.

The unique feature of this invention is that in joining the contact surfaces of cemented carbide and steel, before welding, a defocused beam is applied to a position within about 2 degrees from the contact surface of the cemented carbide, and then the steel side is Approximately 2I+I
It consists of a welding method in which a defocused beam is applied to a position within W1, and then a focused beam is applied to the welding surface.

In an embodiment, high carbon (05
% or more) and cemented carbide 1, a beam with a blurred focus is applied to the carbide side and the steel side without rotating the workpiece to correspond to the penetration depth required in the welding stage. The beam force applied to the joint surface 6 is applied. In addition, O7~/酩(7) Nl + Co, Fe on the joint surface of carbide and steel
Even if an iron group metal such as Nr or a brazing material is inserted, the effect does not change. The position of the beam applied in advance is preferably within 2 afi. When the temperature exceeds 21IJI, the cemented carbide becomes contaminated. Furthermore, it is desirable that the beam be applied in a state where the focus is blurred in advance.

If it is carried out with a focused beam, the cemented carbide will still be stained.

[Example] A cemented carbide tip made of a we-io%co alloy was bonded to three positions of the tip end of a punch made of nine types of 8KH shown in FIG. After finishing by grinding the joint surface 6 of cemented carbide 1 and Tsugu 2, degreasing and demagnetization (S Gauss or less) were performed using Triclean, and then a defocused beam was applied to the cemented carbide side.

Beam conditions are θ/, 2kw-.

Acceleration voltage OkV, beam current /, 6mA, heating time OQ sec.

Met.

Next, under the same conditions, a focused beam was applied to the position a2 from the joint surface of the steel materials. Finally, the diameter of the beam was reduced to Q, 3 mm, and the beam was applied to the contact surfaces of the carbide and steel to perform welding. The joined punches were finished and tested for practical performance.

Compared to the conventional 5KH9 cold-worked bunch, which developed wear and tear on the tip of the punch and became unusable after about 500 pieces, the welding punch of the present invention has a welding punch of 5000 pieces.

It was possible to use up to 1.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing the shape and structure of a punch for punching according to the present invention. 1...Cemented carbide, 2...Steel material, 6...Joint surface.

Claims (1)

[Claims] 1. In a punch made by welding a steel material with a carbon content of 05% or more and a cemented carbide, 2I from the closely joined surface of the alloy
It is characterized by irradiating each alloy with a high-energy beam that has been blurred in advance within +lrn, and then applying the energy necessary to obtain the welding depth while narrowing the beam diameter to join. A method for manufacturing punched nogunchi. 2. Joint number of steel and cemented carbide with carbon θS% or more 0,
A method for manufacturing a punched punch according to claim 1, wherein a thin metal plate of /~/am is inserted and welded. 6. The method for manufacturing a punch according to claim 1 or 2, wherein the high-energy beam is an electron beam or a laser beam.