... welded Usage 1. Low and middle pressure fluid transportation pipeline 2. Casing Tube 3. Boiler Pipe 4. Petroleunm and natural gas ... wellsAPE SPEC 5LA, B, X42APISeamles Steel Tubesand Pipes forHigh Pressure BoilerGB5310-199520G, 20MnG, 25MnG, 15MoG, 20MoG, 12Cr1MoVG, ... ASTM A192 ASTM SA179,SA192,BS3059Seamless Steel Tubes for high pressure --Chemical fertilizer equipmentGB6479-8610, 20G, Q345, Q390, ...