IIW IWT case studies
IIW IWT · Put your knowledge to work in context.
The International Welding Technologist (IWT) is a professional qualification awarded under the International Institute of Welding (IIW) education and training framework. It sits at the technologist level: above the International Welding Specialist and alongside or above the International Welding Engineer depending on the national scheme, and it is aimed at people who translate design intent into workable welding procedures, supervise fabrication, and make decisions about materials, processes and inspection. The IIW IWT case studies are 5 cases and about 3,190 words.
1GMAW-P sidewall lack-of-fusion after a travel-speed increase
A fabricator is producing 8 mm S355J2 butt joints in the PC position with a single-V preparation (60° included angle, 2 mm root gap, ceramic backing). The qualified WPS uses GMAW-P, 1.2 mm G3Si1 wire, Ar/CO2 82/18, 210 A, 26 V, 12 mm wire stickout, and 35 cm/min travel.
718 words, about 4 min2S690QL root HAZ hardness above the 350 HV10 limit
A manufacturer is welding a 30 mm S690QL quenched-and-tempered lifting-beam butt joint with SAW. The qualified WPS specifies 3.2 mm matching wire, agglomerated basic flux, preheat 150°C, interpass 200°C maximum, and heat input 1.8 kJ/mm.
667 words, about 3 min3Fatigue crack at a crane bracket fillet-weld toe
A 20 mm S355J2 bracket is fillet-welded with a 6 mm leg, 200 mm long on both sides, to the flange of a crane runway girder. The bracket carries a cyclic load producing a nominal stress range of 90 MPa at the weld toe for 5×10^6 cycles.
608 words, about 3 min4Duplex 2205 root ferrite and pitting after hydrotest
A chemical plant fabricates 168.3 mm × 7.11 mm UNS S32205 duplex stainless steel pipe spools. The root is GTAW with ER2209 filler, argon shielding and an argon purge; fill passes are GMAW-P with Ar/2%CO2.
602 words, about 3 min5PAUT sizing disagreement on a thick-section butt weld
During fabrication of a 40 mm thick S355J2 pressure-retaining butt weld, access prevents RT. The fabricator uses encoded PAUT with a 2.5 MHz, 64-element probe, 45° shear wave, and a 1 mm side-drilled hole reference.
595 words, about 3 min