J. Storesund et R. Sandstrom, INFLUENCE OF POSTWELD HEAT-TREATMENT ON CREEP-PROPERTIES OF 1CR0.5MO AND 2.25CR1MO WELDMENTS, Materials at high temperatures, 12(4), 1994, pp. 269-276
The creep properties of simulated heat-affected zone, weld metal and c
ross-weld specimens of 1Cr0.5Mo and cross-weld specimens of 2.25Cr1Mo
have been studied with reference to the effect of postweld heat treatm
ent (PWHT). A reduction in the creep rupture strength of up to 20% has
been observed after PWHT. Contrary to what has been previously propos
ed, PWHT was in the present investigation found to have only a margina
l influence on the creep ductility. The creep rate can increase by up
to a factor of 2-4 after postweld heat treatment, probably because of
carbide coarsening during the heat treatment. Preheating at 200-degree
s-C did not affect the creep properties of 2.25Cr1Mo. Overheating, on
the other hand, at 650-degrees-C for 1000 h reduced the rupture time o
f 1Cr0.5Mo by almost an order of magnitude. The tensile strength and y
ield strength of 1Cr0.5Mo were significantly reduced after postweld he
at treatment. Reductions of up to 100-200 MPa were observed both at ro
om temperature and at 550-degrees-C in some cases.