Notch Toughness of Simulated Heat-Affected Zones of 13%Cr Cast Steels

Weldablity of 13Cr Cast Steels (4)

Abstract

The weld heat-affected zone notch toughness of 13Cr cast steels containing Ni (13Cr-Ni) and containing Ni and Mo (13Cr-Ni-Mo) were examined by the welding heat cycle simulating method. The results of these tests are summarized as follows.
(1) When the heat cycle above A_c3 point is applied, the lower the cooling rate in the range from Ms point to Mf point, the more the impact value increases in 13Cr-Ni cast steel.
(2) The lower the interpass temperature and the holding temperature before starting postheating in the range from the Ms point to the Mf point, the more the impact value increased for both 13Cr-Ni and 13Cr-Ni-Mo cast steels.
(3) The impact value was considerably affected by peak temperature of the subsequent heat cycle or postheating temperature which corresponded to tempering of the martensite caused by the proceding heat cycle above A_c3 point. In 13Cr-Ni cast steel, when these temperature were around 650°C, temper brittleness occurred.