Effect of groove type on welding temperature and residual stress for half-pipe jacket

The residual stresses are generated inevitably during welding of half-pipe jacket, which has a great effect on crack and leakage. In This paper, finite element method and an welding experiment, were used(amerant) the temperature field and the welding residual stress for half-pipe jacket made of 304 stainless steel in three types of groove were calculated. The results show that the temperature at the weld root without groove and 2 mm parallel groove does not reach the melting point, which leads to un-melt in the weld metal and results in defects at weld root. The temperature at the weld root in the 45° outside groove exceeds the melting point, which results in a full penetration and generates a good weld. Compared to that without groove, the residual stresse in weld root and the cylinder with 45° outside groove have been reduced 33% and 35% respectively, which is useful to decrease the risk of stress corrosion cracking. The 45° outside groove should be used in the actual welding process, which can ensure the full penetration and reduce the welding residual stress. The methods of no groove and 2 mm parallel groove are forbidden in the welding of half-pipe jackets.