... , Oil, Gas, Steam and so onMechanical PropertiesTensile Strength ≥ 320N/mm2 Yield Strength≥ 195N/mm2Elongation ≥20%Hydraulic TestWorking Pressure: Max ... couplings, British standard, American standard and DIN standard Kinds of mild steel couplings : bends, elbows ,tees, crosses, ... carbon steel ,stainless steel ,alloy steel . Surface of mild steel couplings: cold galvanizing,hot galvanizing,and black ...