MANUFACTURE OF 18NI MARAGING STEEL WITH SUPERIOR RUPTURE TOUGHNESS

摘要

PURPOSE:To considerably enhance the rupture toughness of an 18%Ni maraging steel by combinedly carrying out a soln. heat treatment at a temp. above the recrystallization temp. of austenite and a soln. heat treatment at a temp. below the recrystallization temp. of austenite. CONSTITUTION:A hot rolled 18%Ni maraging steel is subjected to a soln. heat treatment by heating to a temp. above the recrystallization temp. of austenite phase such as 850-950 deg.C. It is cooled to ordinary temp. to provide a martensite structure, and by relieving the work strain, the structure is made homogeneous. The steel is then reheated at a temp. below the recrystallization temp. of austenite phase such as 800-850 deg.C and cooled to ordinary temp. to form martensite. By repeating the soln. heat treatment by heating =2 times, an 18%Ni maraging steel with superior rupture toughness is obtd.