Welding fume collection

Welding was performed by an experienced operator using four different FCW wires; E2209T1 for welding duplex stainless steel of 2205 (UNS {"type":"entrez-protein","attrs":{"text":"S32205","term_id":"346525","term_text":"pir||S32205"}}S32205) type and E316LT1 for welding of the austenitic alloy 316L (UNS {"type":"entrez-protein","attrs":{"text":"S31603","term_id":"346112","term_text":"pir||S31603"}}S31603), and two specially developed E316LT1 electrodes denoted Red1 and Red2, Table ​Table1.1. The chemical composition and/or choice of raw materials in the flux of Red1 and Red2 result in less formation of Cr(VI) in the welding fumes, thus referred to as Cr(VI)-reduced FCWs. Table ​Table22 shows the chemical composition of the base material and filler wires (all-weld metal) measured using X-ray fluorescence (XRF). The shielding gas was argon (Ar) containing 18% CO₂ and the process was operated in the spray arc mode (high melting rate). The wire feed rate was 10 m/min and the welding speed 0.40 m/min. A comparable arc length of 3 mm with a stickout of 20 mm was set for all trials. The current was 190–200 A and the voltage 29.0–29.5 V. Welding was carried out until a sufficient mass of particles (115–161 mg) was collected on each filter. The fume particles were collected on Macherey Nagel MN 640 w (ash content < 0.01 wt%) cellulose filters (Ø 240 mm) using standard particulate fume emission procedures (fume box according to ISO EN 15011-1). The fume particles on the filters were stored for analysis in band-heat sealed plastic bags, sealed immediately after the welding.

Welding fume sample denotation with corresponding filler material and base alloy

Chemical composition of the base material and filler wires (all-weld metal using Ar + 18% CO₂ as shielding gas) in wt%, based on supplier information