welded butt joints of the du150 pipeline from refractory steel, welded by manual arc welding without subsequent heat treatment.

arc austenite butt chromium construction corrosion danger defect defective design drawings du150 edges electric electrode energy factory gas gasoline gloss heat industry inspection joints kerosene life manual many metal molybdenum oil petrochemical pipe pipeline pipelines preparation process project pumping refractory risk safety seam specialist steel subsequent treatment weld welded welder welding welds welwelded work