JPS581004A - Titanium carbide tool steel partly self-bound with austenite iron-chromium-nickel alloy steel - Google Patents

Abstract

PURPOSE:To improve the hardness, abrasion resistance and corrosion resistance of titled steel by allowing part of TiC tool steel wherein austenite stainless steel alloy is infiltered and sintered to a TiC green compact to be self-bound with said alloy steel by said sintering. CONSTITUTION:A TiC green compact 1 is prepd. by compression molding of a mixture of ultrafine powder of TiC and a binder. On the other hand, the powder of austenite Fe-Cr-Ni alloy steel is sintered to make a square timber-like sintered body 2. The end face 1' of the body 1 and the end face 2' of the body 2 are brought into tight contact with each other and these are put in an Mg flask mold 3. A piece 4 of austenite Fe-Cr-Ni steel is put on the body 1, and these are heated in vacuum to infilter the piece 4 into the body 1 and to sinter the body 1. Then, part of the TiC of the body 1 and the Fe of the body 2 react and bind of themselves as a result of this sintering and both are bound firmly.

Description

[Detailed description of the invention] Titanium carbide 7 (TiC) 20-9 o1g amount X (12
Titanium carbide tool steel made by powder metallurgy is composed of a mixture of carbon-containing steel matrix (5 to 87% by weight) and the product name is Ferrotic (a product of Chromalloy Corporation). :'It is known as '. Does this tool steel have superior properties compared to other tool materials? (B) Grinding the wear-resistant carbide tool steel increases manufacturing costs, and (B) reduces the number of pins that occur in the steel matrix. There is a problem that the holes become a source of rust and the corrosion resistance deteriorates even more.

The titanium carbide tool steel according to the present invention does not have the above-mentioned disadvantages (A) and (B) of ferrotic, is harder than ferrotic, and has excellent wear resistance and corrosion resistance. This is because when the titanium carbide green compact is sintered, the austenitic iron-chromium-nickel alloy is simultaneously infiltrated into the green compact on the spot. Further, the titanium carbide tool steel according to the present invention has a self-bonded austenitic iron-chromium-nickel alloy steel body in a part thereof.

A method for ferrotically bonding objects made of other metallic materials is described, for example, in the specification of Japanese Patent Publication No. 12982/1982. The above-mentioned (A) that the ferrotic itself has
This does not eliminate the inconveniences of (B) and (B). That is, this method requires extensive grinding of the sintered ferrotic before or after the bonding process described above, and does not eliminate pinholes in the steel matrix. Moreover, this method requires 7 sintering steps and 12 steps of sintering to bond it to the metallic material.

On the contrary, the composite material according to the present invention consists of (I) sintering of a titanium carbide green compact and (u) other metallic materials of the green compact, especially austenitic iron-chromium-nickel alloy copper. (IN) Infiltrate the austenitic iron-chromium-nickel alloy into the green compact to fill the pores in the green compact and eliminate pinholes in the sintered titanium carbide tool steel. It is made in a single process that includes: The titanium carbide tool steel portion of this composite has excellent fire resistance, wear resistance, and corrosion resistance, and the austenitic iron-chromium-nickel alloy steel bonded thereto, such as SU
S! The 116L portion has excellent corrosion resistance and is easy to machine, so it can be immediately processed into a shape as a part of a machine or a shape that can be assembled into other machine parts.

Therefore, the composite material according to the present invention can be used as a valve for a rotary air conditioner, and also for a screw in a thermoplastic resin injection molding machine (the part corresponding to the high temperature zone of the light leakage part is made of titanium carbide tool steel, and the other part of the screw is made of SUS). 516
It has a wide range of uses such as L).

This invention will be further explained below with reference to Examples.

Example - 1 to 6 micron titanium carbide ultrafine powder is mixed with 1% by weight of paraffin wax, and this is compression molded at a pressure of 3/- to produce a 10 x 10 x 15 square block shaped compact. (Symbol 1 in the attached drawing) was made. On the other hand, powder of austenitic stainless steel (BUS 516 L) was sintered to produce 1
A square-shaped sintered body (reference numeral 2 in the attached drawing) of 0mX 10ss An 8U8 plate of 10×15 x 2× was placed in a magnesium frame mold (number 6 in the attached drawing) so as to be in contact with the powder compact 1.
A piece of 316L stainless steel (number 4 in the attached drawings) was placed. In a vacuum of 10-1 to 10-'■Hp,
Heat at 1420℃ for 1 hour.

The BUS 516L stainless steel piece 4 was ink irradiated onto the green compact 1, and the green compact was sintered, but its capacity did not change and it did not shrink.

1+, sintered compact powder body 1 and sintered compact 2 are firmly bonded together.

This appears to be due to a reaction between a part of the titanium carbide of the powder compact 1 and F of the base metal of the sintered compact 2, resulting in self-bonding. Even through quenching, the sintered green compact 1 does not undergo any major dimensional changes and remains round.

[Brief explanation of the drawing]

The accompanying drawings are illustrative drawings showing one method of making the composite material of this invention. 1... Titanium carbide compact 2... Austenitic stainless steel copper body 1/, 2/...
・・Contact end face between green compact and stainless steel body 6 ・・Magnesium frame mold 4”° stainless steel piece Patent applicant Chugai Electric Industry Co., Ltd. Agent Keiji Takaishi

Claims (1)

[Claims] A titanium carbide tool steel made by infilling and sintering an austenitic iron-chromium-nickel alloy into a titanium carbide compact, and austenitic iron-chromium-nickel alloy self-bonded to a part of this tool steel by the sintering described above. A composite material made of nickel alloy steel.