TWI Industrial Member Report Summary 373/1988
By T G Gooch and B J Ginn
Low carbon 12%Cr steels with a duplex martensite-ferrite structure have been developed to give improved corrosion resistance over common structural steels. However, such alloys tend to transform to ferrite in the high temperature heat affected zone (HAZ) of fusion welds, with resultant grain growth and reduction in toughness. The present work examined the effects of varying arc energy and of reheating during multipass welding on HAZ structure and toughness of representative commercial alloys.
Manual metal arc (MMA) butt welds and simulated samples were produced from 12mm plate, and HAZ Charpy V notch impact tests to BS 131: Part 2: 1972 were carried out over a range of temperature. All samples were tested in the as-welded condition. Metallographic and fractographic examination were undertaken.