... boiler, ship, liquid service, petroleum cracking, chemical ferticizer equipment, drawing-oil-equipment and structure purposes.6.Surface: oiled or black painted ... ,API5L,GRB,X42-X65 and so on 5.Packaging: Painting black,cap, in bundle6.Application: Petroleum,smelting,foodstuff,power ... ,API5L,GRB,X42-X65 and so on 5.Packaging: Painting black,cap, in bundle6.Application: Petroleum,smelting,foodstuff,power ...