Reheat cracking is a failure mechanism seen in welds fabricated from high temperature creep resistant materials. A new feature test specimen (ring-weld) has been designed to reproduce reheat cracking in the laboratory. The 3D residual stress distribution in an Esshete 1250 ring-type test specimen has been measured in the as-welded state (RB15173) and after 1,265 hours heat soak at 650 deg C (RB520194). The specimen is currently being heat soaked for a further 8,700 hours during which timeframe reheat crack initiation is predicted to occur. In the present experiment the residual stress field in the ring-weld will be re-measured after 10,000 hours creep relaxation. This will provide a unique measured dataset that can be used to validate the initial weld residual stress distribution, short and long term stress relaxation at elevated temperature and reheat creep crack initiation models.