Abstract:
The susceptibility to solidification cracking of unstabilized and stabilized ferritic stainless steels was investigated using self-restrained Houldcroft and Modified Varestraint-Transvarestraint (MVT) tests. Nine steel grades of unstabilized and stabilized ferritic stainless steels were used in this study. Seven steels comprising an unstabilized, two monostabilized (Ti and Nb) respectively, three dual stabilized (Ti + Nb), and a dual stabilized containing Mo were used for the self-restrained Houldcroft method. A monostabilized Nb and dual stabilized (Ti + Nb) grades (experimental alloys) and commercial grades of an unstabilized and a dual stabilized (Ti + Nb) ferritic stainless steels were employed in the MVT test. Autogenous gas tungsten arc welding at a speed of 6 mm/s, 3 mm/s, and 1 mm/s was done for the Houldcroft test and welding at a speed of 6 mm/s and 3 mm/s for MVT test. The results of the tests were evaluated by measuring the crack length, considering the microstructure and using multiple linear regression analysis of the crack length. The MVT method was successful in demonstrating the deleterious effect of Nb on ferritic stainless steels. Cracking of the Houldcroft samples was dependent on Ti, welding parameters, and the weld bead geometry.
