Study on Temper Resistibility for V-Cr-Mo-Nb-W High Speed Steel

The microstructure and mechanical properties of composite rollers made of a new type of V-Cr-Mo-Nb-W highspeed steel after air-cooling quenching and tempering were studied.The results show that when the heating temperature is under 800 ℃ and after air-cooling,the hardness of the steel decreases with the heating temperature increasing,the lowest hardness is at 800 ℃;while the heating temperature is from 800 ℃ up to 1050 ℃ and after air-cooling,the hardness of the steel increases with the heating temperature increasing and reaches the highest in the range of 1000～1050 ℃;the steel possesses very good resistance to tempering after heating at 1050 ℃×1 h air-cooling and tempering at 600℃,the hardness is more than 58HRC.The hardness is not influenced by casting conditions.The steel has best softness property at 800 ℃ heating and air-cooling quenching and is easy for machining.