Fundamentals of Welding Design

A: That's the most common mistake — confusing leg size with throat. The effective throat is about 0.707×6 ≈ 4.2 mm, giving an area near 420 mm² over 100 mm length. Twenty kilonewtons over that area lands you around 48 MPa, even before any code knockdowns. You're not designing the final weld here, just checking if the sketch is nonsense.

A: That's the most common mistake — dropping the 0.707 factor or misapplying safety factors inside the stress calculation. Two welds mean double the throat area: 2×150×0.707×5 ≈ 1060 mm². Thirty kilonewtons over that area keeps you in the high‑20s MPa range, which is all you're being asked for at this stage.

A: That's the most common mistake — jumping to NDT or paint arguments before confirming the weld was even made under an approved WPS by a qualified welder. Visual acceptance is the gate; without it, later inspections don't mean anything, especially when the clock is ticking toward FAT.

A: That's the most common mistake — importing oil-and-gas failure modes into a plain outdoor structure. Here it's moisture, oxygen, and geometry. The weld toe creates a crevice-like condition that holds water, so basic atmospheric corrosion governs, not exotic cracking mechanisms.