INFLUENCE OF CARBON, NICKEL, COBALT, TUNGSTEN AND MOLYBDENUM ON PROPERTIES OF 9.5% TUNGSTEN CHROMIUM HOT-WORKING TOOL STEEL

Abstract

The influence of C, Ni, Co, W and Mo on properties of the hot working tool steel containing 0.3% C, 9.5% W, 2.5% Cr, and 0.4% V was investigated.
The Result obtained were as follows:
1) The addition of Ni lowered the critical point, and enhanced the hardenability remarkably. Ni, being a gamma-forming element, led to a decrease in the amount of ferrite existing at high temperature.
2) The addition of Co raised the critical point and Ms-point and improved the tensile strength and impact value at elevated temperature at the higher quenching temperature.
3) As the carbon content increased, the hardenability increased and the Ms-point was lowered. The tensile strength increased and the impact value decreased at room and elevated temperatures in parallel with the increasing carbon content. 4) The addition of Mo lead to the presence of additional quantities of ferrite at the heattreating temperature and decreased the hardenability.