On thin titanium the margin between full penetration and a hole is small, and the heat does not escape. Fit-up, chill bars, pulse settings and travel speed decide the outcome, along with knowing how to close a blow-through.
Duplex stainless carries both austenite and ferrite, and the balance is what gives it strength and corrosion resistance. Heat input, filler choice, interpass control and distortion all decide whether the weld keeps that balance.
Titanium and stainless cannot be fused directly without a brittle intermetallic layer at the interface. Here is how a barrier layer works, why copper is the usual choice, how the joint is sequenced, and what coupons actually prove.
Titanium absorbs oxygen, nitrogen and hydrogen while it is still hot, so the torch alone is not enough. This article covers trailing shields, purge chambers, internal dams and tape, and how to read bead colour as a record of shielding.
In a multi-part assembly the order of welding decides how much each joint can move. Free joints first, restrained joints last, and access sets the rest.
