The Heat Treatment Process On The Organization And Performance Of 1cr16ni3cumowv

The heat treatment on effect of structure and properties of the new precipitation hardening stainless steels lCrl6Ni3CuMoWV was investigated. With the heat treatment, the change rule of the size, shape, volume percent and distributing of the second phases was investigated by the use of optical metallography, SEM and TEM. Using the results of experiment, the strengthening rule of lCrl6Ni3CuMoWV was researched.The CUT curve and critical transformation points of lCrl6Ni3CuMoWV were obtained. The A_s and A_f were 640℃ and 745℃ respectively. The Af, was decreasing with quickening of cooling rate.The structure of lCrl6Ni3CuMoWV was compose of martensite, some remaining austenite and some ferrite after quenching. The remaining austenite was 18.63% by 1070℃1h+-70℃2h+100℃2h. When cooling treatment temperature was-192℃, the remaining austenite was 14.02%and it was 16.47% by 1100℃1h+-192℃2h+100℃2h.The best way of heat treatment was 1100℃1h+-192℃2h+485℃2h, then the σ_b and A_KU2 was 1610MPA and 88J respectively.The lCrl6Ni3CuMoWV were main to block movement of dislocation lines by the second phases precipitation, so we could improve the intensity of material. They were closely correlative between size,shape,volume percent and distributing of the second phases and properties of testing steels .With increase of aging temperature, the size, shape, volume percent and species of the second phases happened to change. The size of MX, M₂X and ε -Cu changed from several nm to more than ten nm. The shape changed from globosity to cosh shape, dish shape and strip shape, meanwhile space of grain became bigger and bigger, decreased the density of dislocation , martensite laths reverted and precipitation hardening increased firstly and decreased after. When it is aged over 600 ℃,We could observe the big grain M₂₃C₆.