Abstract
Cross-weld tensile specimens were machined from welds made in 2·25 Cr-1 M 0 steel plate using either AISI 316 or Inconel 182 filler metals. Low-ductility failures, close to the ferritic steel/weld metal interface, were produced by iso-stress temperature-acceleration tests at either 62 or 100 MN m−2 over the temperature range 575°-640°C. The endurances of joints made using Inconel 182 weld metal were greater than those made using AISI 316 weld metal by factors of ∼2·5 and 3 for tests at 62 and 100 MN m−2, respectively. The fracture morphology has been studied by optical and scanning electron microscopy. By comparison with previous investigations, a change in the short- and long-term fracture mechanism of nickelbased joints is identified. The interfacial damage has been measured and is used to discuss the relative importance of creep-strength mismatch and thermal-expansion coefficient differences between the weld metal and ferritic steel in controlling the fracture of the joint.
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