Quenching process of hydraulic motor housing

The key raw material of the machine shell is nodular cast iron. The quenching effect of nodular cast iron is to better obtain pearlite mechanism, optimize the crystal and make the mechanism symmetrical, so as to improve the compressive strength, strength and wear resistance of BM6 hydraulic motor parts, and can be used as the prior heat treatment process of induction quenching.

(1) High temperature quenching: High temperature quenching process is the casting heat to above the eutectoid temperature range, generally is 900 ~ 950 ℃, adiabatic 1 ~ 3 h, the base material institutions all martensite is changed, then released air cooling, make drivers hydraulic motor in the eutectoid temperature range, get pearlite base material because of the fast cooling of high silicon content of thick wall pipe casting, should choose air-cooled, Or spray refrigeration, to ensure that after quenching can get pearlitic ductile iron

(2) the ultra-low temperature quenching: ultra-low temperature quenching process is to put the casting heat to the eutectoid temperature range, which is 820 ~ 860 ℃, the heat insulation 1 ~ 4 h, the base material agency part of martensite is changed, then released pearlite after air cooling temperature quenching, the decentralized microstructure of nodular cast iron, can improve the ductility of castings with the hydraulic oil motor plastic deformation.

Because ductile cast iron heat transfer is weak, elastic mold and relatively large, after quenching there is a great thermal stress in the casting, so most of the processing plants after quenching, also carry out a to the ground stress quenching (often called quenching), that is, heating to 550~600℃, heat insulation for 3~4h, then announced air cooling.

Generally, nitriding is applied to the workpiece with large load and high relativity of contact fatigue, focusing on deep and deep layers. The effect of soft nitriding is fast permeability, generally used to load small product workpiece, shallow permeability layer provisions. There are two basic nitriding types, hard nitriding and soft nitriding.