Advantages of the Application of the Temper Bead Welding Technique During Wet Welding.

Jacek Tomków,Grzegorz Rogalski,Jerzy Łabanowski,Dariusz Fydrych

doi:10.3390/ma12060915

Abstract

Thermo-mechanically rolled S460ML steel was chosen for welding in underwater wet welding conditions by covered electrodes. The main aim of this study was to check the weldability for fillet welds in a water environment by controlled thermal severity (CTS) tests and to check the influence of temper bead welding (TBW) on the weldability of the investigated steel. Non-destructive and destructive tests showed that S460ML steel has a high susceptibility to cold cracking. In all joints, hardness in the heat-affected zone (HAZ) was extended to the 400 HV10 values. Microscopic testing showed the presence of microcracks in the HAZ of all welded joints. TBW was chosen as the method to improve the weldability of the investigated steel. This technique allows for the reduction of the maximum hardness in the HAZ below the critical value of 380 HV10, as stated by the EN-ISO 15614-1:2017. It was determined that for S460ML steel, from the point of view of weldability, the pitch between two beads should be in the range 75%–100%. Also, if the pitch between two beads increases, the hardness, grain size, and number of cracks decreases. In all specimens where the hardness of the HAZ was below 380 HV10, there were no microcracks.

Highlights

The research into the processes of joining in underwater conditions is developing annually.There are many studies on the use of friction stir welding (FSW) in this environment [1,2].FSW produces a small heat-affected zone (HAZ), which creates better mechanical properties in joints [3].the most popular method of joining is still arc welding
The diver/welder is in direct contact with the water, but the welding area is located in a special chamber that isolates this area from the surrounding water environment [6,7]
The results showed that the temper bead welding (TBW) technique was more effective for steel with a CeIIW lower than 0.4%

Summary

Introduction

The research into the processes of joining in underwater conditions is developing annually.There are many studies on the use of friction stir welding (FSW) in this environment [1,2].FSW produces a small heat-affected zone (HAZ), which creates better mechanical properties in joints [3].the most popular method of joining is still arc welding. The second method is welding with the use of a local dry chamber. In this method, the diver/welder is in direct contact with the water, but the welding area is located in a special chamber that isolates this area from the surrounding water environment [6,7]. The final and most common method of underwater welding is wet welding, where the diver and welding area are in contact with the water environment. This method is the cheapest and can be used for many applications, including offshore and marine structures, which may require repairs underwater [8]

Objectives

Methods

Results

Conclusion