Influence of heat treatment after welding on the microhardness of steel joints in marine platforms

Abstract

Weld joints in fixed marine platforms must be highly reliable. Certain zones of the weld seam may be very hard and hence may act as stress concentrators. Therefore, in some cases, additional heat treatment is required after welding. The microhardness of the basic sections in the weld joint of microalloyed low-carbon streel sheet (thickness 60 mm) obtained by thermomechanical rolling is investigated. Two-coordinate measurements of the microhardness in the basic thermal-influence zones are described. The influence of postweld heat treatment on the microhardness of opposite walls of the weld joint is determined.