Induction Heating in Underwater Wet Welding—Thermal Input, Microstructure and Diffusible Hydrogen Content

Abstract

Hydrogen-assisted cracking is a major challenge in underwater wet welding of high-strength steels with a carbon equivalent larger than 0.4 wt%. In dry welding processes, post-weld heat treatment can reduce the hardness in the heat-affected zone while simultaneously lowering the diffusible hydrogen concentration in the weldment. However, common heat treatments known from atmospheric welding under dry conditions are non-applicable in the wet environment. Induction heating could make a difference since the heat is generated directly in the workpiece. In the present study, the thermal input by using a commercial induction heating system under water was characterized first. Then, the effect of an additional induction heating was examined with respect to the resulting microstructure of weldments on structural steels with different strength and composition. Moreover, the diffusible hydrogen content in weld metal was analyzed by the carrier gas hot extraction method. Post-weld induction heating could reduce the diffusible hydrogen content by −34% in 30 m simulated water depth.

The Problem of Selecting the Parameters of the Numerical Model of the Heating Process with a Point Heat Source and Its Experimental Verification

“…As a modern area of development of this technology can be mentioned work related to the welding of underwater structures. Elements of this type must, for technological reasons, be locally heated (preheating or tempering) using, for example, an induction source [ 6 , 7 ].…”

Effects of Magnetic Fields in Arc Welding, Laser Welding, and Resistance Spot Welding: A Review

“…To further improve the welding quality of the joint, in recent years, numerous scholars have developed various welding‐assisted methods. For instance, magnetic field‐assisted, [ 1 ] ultrasonic‐assisted, [ 2,3 ] induction heating‐assisted, [ 4,5 ] laser‐assisted, [ 6,7 ] vibration‐assisted, [ 8,9 ] and arc‐assisted laser welding [ 10 ] (LW) are applied. The magnetic field‐assisted welding method, in particular, has garnered a lot of attention and interest because of its simple components, low cost, and effective weld formation.…”

The Metallurgical hydrogen as an indicator and cause of damage to rolled steel: Hydrogen diagnostics of fracture

“…Tests for hydrogen T induced cracking or resistance to hydrogen cracking are also standard [4]. The study of the effect of natural, so-called "metallurgical" hydrogen, has long passed into the field of industrial testing [6] and is currently being studied only in the weld metal [7,8]. In other cases, for each type of alloy there are maximum allowable concentrations of hydrogen which are controlled, most often, directly in the molten metal at the production stage.…”