Weld Procedure Qualification

Abstract

Welding codes and standards usually require the qualification of welding procedures prior to being used in production. This is to ensure that welds will meet the minimum quality and mechanical property requirements for the application. This article provides an overview of the welding procedure qualification guidelines and test methods. It also reviews the codes, standards, and specifications that govern the design and fabrication of welded structures for the procedure qualification details that are appropriate for a given application.

Evaporation phenomena of magnesium from droplet at welding wire tip in pulsed MIG arc welding of aluminium alloys

“…2 Fume formation has been studied in many industrial materials. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] In mild steel, the fumes are composed of 40-60%Fe and several per cents of Mn or Si. [3][4][5]10 In stainless steel, the fume compositions are reported to be 15-35%Fe, 11-17%Cr and 4-10%Ni.…”

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] In mild steel, the fumes are composed of 40-60%Fe and several per cents of Mn or Si. [3][4][5]10 In stainless steel, the fume compositions are reported to be 15-35%Fe, 11-17%Cr and 4-10%Ni. 4 In aluminium alloy, the fumes contain 40-50%Al and 5-10%Mg.…”

“…18,19 The welding fumes can be affected by many welding conditions, such as shielding gas, arc current and voltage, which may change metal transfer modes. [4][5][6]8,9,11,13,15 When the metal transfer mode changes from globular to spray, 6,15 the fume formation rate generally decreases. Concerning the arc current, the pulsed current reduces the fume formation rate, especially in alternating current mode.…”

“…Concerning the arc current, the pulsed current reduces the fume formation rate, especially in alternating current mode. 5,17 Fume formation mechanisms have been studied by many researchers. The potential fume sources are classified as follows: 12 (i) the droplet surface (ii) exploding droplet of the constricted neck during detachment (iii) weld pool (iv) spatters.…”

“…6, 8, 9, 11, 13, 15 When the metal transfer mode changes from globular to spray,6, 15 the fume formation rate generally decreases. Concerning the arc current, the pulsed current reduces the fume formation rate, especially in alternating current mode 5, 17…”