Surface treatment method for alloy steel W18Cr4V mold parts

Abstract

The invention discloses a surface technology improvement for alloy steel W18Cr4V mold parts. The surface technology improvement relates to that gas nitriding treatment performed on surfaces of mold parts includes four steps, namely four processes of drawing up, degassing, heating and cooling. In the degassing process of the surface gas nitriding to alloy steel W18Cr4V mold parts, the proportions of ammonia gas and a gas carrier (RX) are 50%, respectively. In the heating process, a nitriding temperature is within a range of 400-500 DEG C and is kept for 5 hours, and the decomposition of the ammonia gas is 35-40%; a working temperature of a heating furnace is not high and usually not higher than 700 DEG C. However, an extremely high requirement is made to the furnace temperature uniformity of the furnace; after the gas nitriding treatment, a nitriding depth ranges from 0.05 to 0.07mm and the hardness ranges from 900 to 1200HV. After the surface technology for alloy steel W18Cr4V mold parts is improved, the surface hardness, abrasion resistance and anti-scuffing property, and especially the adhesive wear resistance (anti-seizing capability) of the parts can be improved; the thermal stability is improved; the corrosion resistance of non-stainless steel is improved, and the fatigue resistance of the same is improved, resulting in low fatigue notch sensibility.

Description

technical field [0001] The invention relates to the surface technical improvement of alloy steel W18Cr4V mold parts. Background technique [0002] Some difficult-to-machine materials (such as stainless steel, titanium alloy) or high-hardness materials are also formed by molds. The precision of mold parts is also getting higher and higher, and they will be scrapped if they are slightly worn. Therefore, although the quenched and tempered mold parts have high hardness, their durability is still difficult to meet the increasing performance needs. People use surface strengthening method or surface modification technology to further improve the performance of mold working parts. There are many ways to strengthen the surface of mold parts, such as surface chemical heat treatment, surface quenching, physical or chemical vapor deposition, surface coating, laser surface alloying and so on. However, from a comprehensive investigation of maturity, economy, convenience and other aspec...

AI Technical Summary

Problems solved by technology

Solid nitriding has basically been eliminated due to extensive processes, poor working conditions, difficult quality control, and poor results.

Although liquid nitriding or salt bath nitriding is carried out in a toxic cyanide salt bath, although the effect is good, it is a poisonous and harmful operation (it is also called non-toxic, but its waste is still harmful). Prevention, but it is inconsistent with the development trend of modern pollution-free heat treatment (green heat treatment), and it is restricted, not promoted or banned in our country

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