EFFECTS OF HEAT TREATMENT ON STRUCTURE AND PROPERTIES OF HIGH SPEED STEEL ROLL CONTAINING HIGH MOLYBDENUM AND VANADIUM CONTENT

The effects of quenching temperature,cooling pattern,temper temperature and temper times on the structures and properties of high speed steel(HSS) roll have been researched.The results show that as quenching temperature is lower than 1 050 ℃,the hardness is increased along with the increase of quenching temperature under oil cooling,while quenching temperature excels 1 100 ℃,the hardness will decrease along with the increase of quenching temperature.Under the condition of salt bath and air cooling,the effect of quenching temperature on the hardness is similar to that,but the quenching temperature obtaining highest hardness is higher than that of oil quenching.Temper temperature is lower than 350 ℃,the hardness of HSS has little change,while it excels 475 ℃,the hardness of HSS will increase along with the increase of temper temperature,and highest hardness is obtained at 525℃,and temper temperature continue to increase,the hardness will decrease.Two times temper has little effect on the hardness,three times temper will decrease the hardness.The air cooling of HSS roll has lower hardenability,oil cooling is easy to produce crackle,HSS roll quenching in salt bath has high hardenability,the surface hardness is high and even,and has excellent wear resistance.