Welding problems with thin brass plates and tungsten inert gas pulse welding

Abstract

Brass materials are widely used as engineering materials in industry because of their high strength, high corrosion resistance, and high electrical and thermal conductivity. They are easily shaped and they possess a pleasant appearance. However, it is difficult to weld brasses. The main problem with these alloys in fusion welding is the evaporation of zinc during the welding process. After welding, the weld metal becomes porous. Moreover, since the amount of zinc in the alloy is reduced due to evaporation, the brass material loses the physical and chemical properties which it normally possesses. Studies on weldability of brass materials are very few. There is very little information concerning the weldability of brass materials in the literature and general definitions are often seen. It is impossible to find studies on experimental investigations of the welding of brass materials apart for a few exceptions. There are virtually no studies to support experimental data about whether welding of brass materials is possible. The purpose of the present study is to determine suitable parameters by investigating the weldability of brass materials, and the difficulties involved. In order to enable low and controlled heat input into the welding bead, TIG pulse welding is used during experimental studies. The physical and chemical properties of welding beads (penetration, tensile strength, Erichsen deep drawing value, chemical composition of internal structure) have been determined and evaluations have been made. STWJ/394

Prediction of the optimized welding parameters for the joined brass plates using genetic algorithm

“…The thickness of the brass material used in the experiments was 1 mm. The data, related to welding current, welding velocity and arc length are taken from these experimental results [8].…”

“…The study conducted by Meran et al [8] has indicated that the selection of an unsuitable welding current and welding speed leads to some holes, zinc oxide and the excess penetration. The welding bead of the desired quality was not formed [8]. Evaporation takes place, pores appear in the welding bead, zinc oxide precipitates on the surface of welding bead and the brass loses its yellowish color and takes a reddish color.…”

“…Zinc with the lower boiling temperature evaporates more than copper [7]. The study conducted by Meran et al [8] has indicated that the selection of an unsuitable welding current and welding speed leads to some holes, zinc oxide and the excess penetration. The welding bead of the desired quality was not formed [8].…”

“…In this condition the surface becomes gray or sometimes black. The reason for the oxidization due to zinc and copper is summarized in [8]. Theoretically, zinc evaporation during the welding may be prevented by limiting the heat input into the welding pool [9].…”

“…Velocity, ν (mm/s) Comparison of the experimental result[8] and GAWCEM results based on welding current.…”