Valve finisher surface modified processing method

Abstract

The invention relates to a surface modification processing method for the engine critical component, which belongs to the field of the steel surface chemistry thermal treatment processing technology. The processing method comprises: nitriding for the air valve finisher by using the plasma technology, adding carbon-containing gas in the nitrogen-containing gas at the late stage of nitriding and carrying out the nitrocarburizing, and placing the mould in the steam oxidizing furnace for surface oxidizing treatment. The mould treated by said technology has excellent mechanical property, improved surface hardness, improved compression resistance, improved wear resistance and improved thermal fatigue resistance.

Description

technical field [0001] The invention relates to a surface modification treatment processing method of a precision forging die of a valve, a key component of an engine, and belongs to the technical field of steel surface chemical heat treatment processing. Background technique [0002] Valves are key parts of various engines and are widely used in industries such as automobiles, aircraft, agricultural machinery and ships. When the valve is scoured by high-temperature gas and the friction and wear of the valve seat, it is easy to fail and be scrapped. In order to improve the performance of the valve, its material selection has gradually changed from carburizing steel to heat-resistant stainless steel and high-temperature alloy. The new materials used in the valves generally have higher high-temperature strength than conventional materials, and their resistance to thermal deformation is increased accordingly. [0003] Valve precision forging dies are generally made of hot work...

AI Technical Summary

Problems solved by technology

When the valve is made of heat-resistant stainless steel, high-temperature alloy and other materials, its thermal deformation resistance is improved, but the collapse and wear of the mold become more significant

If the heat treatment process is adjusted to adjust the plasticity and toughness of the hot work die steel and obtain high strength to improve the ability of the die to resist compression and wear, it cannot fundamentally solve the problem of the obvious decline in the life of the die

[0004] In addition, high-speed steel with better thermal strength and even powder alloy are used to manufacture valve precision forging dies. Since high-speed steel and powder alloy materials can still maintain high hardness at high temperatures, the collapse and wear of the die are controlled. , but the ability of these materials to withstand alternating cold and heat shocks is relatively poor, and the thermal fatigue on the mold surface occurs and develops faster

Moreover, the use of high-speed steel, especially powder alloy molds, will greatly increase the cost of molds