Optimization of machine parameters for an A487 Steel welding process

Aim of this work is to show results of the characterization of the repairing process of a mud pump module through the GMAW process. 33 shielded-type-weld test coupons were prepared made of A487 carbon steel, which is the main material composing the mud pump under analysis. Design of experiments was realized varying current, voltage, travel speed and electrode length (electrical stickout ESO). Filler material was ER 312 stainless steel, and the shielding gas was a mixture of Ar-CO2-H2. The maximum penetration depth and micro hardness were measured for each coupon and compared. Maximum penetration depth achieved was 3.3 mm, for a 260 A current, 30 volts, travel speed of 70 cm/min and an electrode length of 12.7 mm. Likewise was performed the metallurgical evaluation of weld, observing that microstructure and other properties are adequate for the pretended use of the joint.