Creep Continuum Damage Constitutive Equations for the Base, Weld and Heat-Affected Zone Materials of a Service-Aged {1 over 2}cr{1 over 2}mo{1 over 4}v:2{1 over 4}cr1mo Multipass Weld at 640 °c

Creep continuum damage constitutive equations have been determined for the base, weld and heat-affected zone materials of a service-aged 1/2Cr1/2Mo1/4V:21/4Cr1Mo multipass weld at 640°C. The base and weld material properties were determined from uniaxial creep and notched bar creep rupture test results. The properties of the heat-affected zone material were determined from impression creep tests, waisted cross-weld specimen tests and notched cross-weld specimen tests. At the test temperature of 640 °C, surface oxidation occurs. For the uniaxial creep and notched bar creep tests, this oxidation was considered not too significant. However, for the low-load impression creep tests, the oxidation depth was comparable to the indentation depth.