Heat treatment method for accelerating precipitation of nanoscale carbides in w-containing alloy steel

Abstract

A heat treatment method for accelerating precipitation of nanoscale carbides in a W-containing alloy steel, including: homogenizing a billet at 1100-1200° C. for 24-48 h followed by furnace cooling to room temperature; then austenitizing the billet at 850-1000° C. for 20-40 min followed by quenching in iced brine; heating the billet to 650-750° C. with a rate of 3-7° C./min under a vacuum of 10−3-10−2 Pa and a magnetic field of 10-14 T, isothermalizing the billet for 0.5-2.5 h and cooling the billet to room temperature. The chemical composition of the billet is: 0.06-0.14 wt % C, 1.50-3.00 wt % W, <0.01 wt % P, <0.005 wt % S, Fe and an inevitable impurity. A temperature of the iced brine is −3 to −1° C. The invention has the advantages of simple process, low cost and shortened production period. The W-containing alloy steel treated by the method has improved strength.

What is claimed is: 
     
         1 . A heat treatment method for accelerating precipitation of nanoscale carbides in a W-containing alloy steel, comprising:
 homogenizing a billet at 1100-1200° C. for 24-48 h followed by furnace cooling to a room temperature;   austenitizing the billet at 850-1000° C. for 20-40 minutes followed by quenching in iced brine; and   heating the billet to 650-750° C. with a rate of 3-7° C./min under a vacuum of 10 −3 -10 −2  Pa and a magnetic field of 10-14 T, isothermalizing the billet for 0.5˜3.0 h and then cooling the billet to room temperature;   wherein a chemical composition of the billet is 0.06-0.14 wt % C, 1.50-3.00 wt % W, <0.01 wt % P, <0.005 wt % S, Fe and an inevitable impurity.   
     
     
         2 . The method of  claim 1 , wherein a temperature of the iced brine is −3 to −1° C.