Effect of Equal Channel Angular Pressing on Microstructure and Properties of T250 Maraging Steel
Equal channel angular pressing was successfully carried out on the solution-annealed steel with two passes at room temperature through the route C. Influences of ECAP multi-passes on microstructure and mechanical properties of T250 maraging steel were studied with metalloscope, TEM and mechanical property test. The results show that a well grain refinement can be achieved by ECAP forming. The martensite lath is elongated to more narrow bands, and the width is decreased from 0.8 μm to 0.2 μm after two passes ECAP deformation. Density of dislocations in lath is increased and distortions are serious. After two passes ECAP deformation,the microhardness is enhanced about 24.7 % from 336.3 HV to 419.8HV, and the growth range of one pass is significantly greater than two pass.