张公山寨
Excuse me, the pipe fittings of ASME carbon steel, the design temperature is -46 degrees, ..
As the head of the company's procurement and production department, he has nearly 20 years..
张公山寨
Does the conical shell in the middle of the two cylinder need folding..
光头强
Excuse me, how to understand the safety factor of the fixed P19 page material..