Structural Transformation of High Vanadium High Speed Steel during Tempering and its Influence on Abrasive Wear Performance of the Material

Abstract

The expansion curves during the procedure of continuous cooling which high vanadium high speed steel (HSS) was tempered with 250°C, 550°C and 600°C after 1050°C quenching were determined by the Gleeble-1500D thermal simulation test device, and the curves were analyzed subsequently. The hardness and microstructure of high vanadium HSS under different tempering temperatures were analyzed by means of SEM, TEM and X-ray diffraction, and the influence of tempering temperature on the hardness and retained austenite were discussed. At the same time, the wear resistance of the material at different tempering temperatures was studied by the HST-100 friction wear testing machine, and the influence of microstructure on wear resistance was analyzed further. The studies show that the structures are not transformed at 250°C tempering with cooling rate of 0.5°C/s; The retained austenite transformed to martensite at about 390°C when 550°C and 600°C tempering. Wear test shows that the abrasive wear performance is excellent with 550°C tempering after 1050°C quenching because of the decrease of the amount of retained austenite, therefore the heat treatment of 550°C tempering after quenching of high vanadium HSS is optimal.