Solidification Cracking Studies on Steels

Three steels namely, Cr-Mo steel equivalent to 4130, modified 4340 steel Containing higher silicon and high nickel whose strength is equivalent to maraging steel 250 and a maraging steel have been studied for their solidification cracking behaviour during continuous current gas tungsten arc welding employing varestraint test system. The Cr-Mo steel was also subjected to pulse mode of gas tungsten arc welding to understand the influence of current pulsing on solidification cracking behaviour. Cr-Mo steel exhibited least solidification cracking tendency while modified 4340 steel (silicon steel) showed marginally higher cracking tendency than the maraging steel. Cr-Mo steel exhibited a greater tendency to cracking in pulsed mode of welding than in conventional welding. The observed cracking tendency of cracking in pulsed mode of welding is explained on the basis of possible differences in the weld thermal history between conventional welds and pulsed welds.