New projects

Launchpad, November - December 2007

For a full list of proposed, active and closed projects see here

Advanced weldments in 9-12%Cr Steel for super critical and ultra super critical power plants

Launched: November 2007
Cost per Sponsor: £60,000 pa, three payments
Project Leader: John Rothwell

Over the past 40 years, the creep strength of 9-12%Cr steels has steadily improved to allow the design of high efficiency power plant. Today grades such as 91 and 92 are commonly used and are capable of operating at temperatures above 600°C. However, welded joints in these materials perform poorly and suffer from the phenomenon of Type IV cracking even at stresses below design levels. This has led to premature failures. To mitigate against Type IV cracking and extract the full benefit from the advanced steels, the performance of weldments in long term service must be improved. These improvements are possible through modification to the welding process. Welding processes with a short thermal cycle and a narrow HAZ appear to minimise the weakening of the weldments. A Group Sponsored Project is therefore being proposed with the aim of mitigating Type IV cracking through the applications of suitable advanced welding processes.