1. Gas shielded metal arc welded steel pipe
A steel pipe with a straight weld seam welded by continuous gas shielded metal arc welding process. There are more than one inner and outer weld seam each.
2. Gas shielded metal arc welding and submerged arc welding combined welded steel pipe
A steel pipe with a straight weld seam welded by two welding processes. Gas shielded metal arc welding should be continuous and performed first, followed by automatic submerged arc welding. There are more than one inner and outer weld seam each.
3. Double-seam submerged arc welded steel pipe
A steel pipe with two straight weld seams welded by automatic submerged arc welding process. The positions of the two weld seams should be about 180° apart. For each weld seam, there should be no less than one inner and outer weld seam. All weld seams should be tested after forming and welding.
4. Double-seam gas shielded metal arc welded steel pipe
A steel pipe with two straight welds welded by gas shielded metal arc welding process. The positions of the two welds should be about 180° apart. For each weld, there should be no less than one inner and outer weld. All welds should be tested after forming and welding.
5. Double-seam gas shielded metal arc welded and submerged arc welded steel pipe
A steel pipe with two straight welds welded by two welding processes. The positions of the two welds
should be about 180° apart. For each weld, continuous gas shielded metal arc welding should be performed first, and then submerged arc welding should be performed. There should be no less than one inner and outer weld. All welds should be tested after forming and welding.
6. Spiral seam submerged arc welded steel pipe
A steel pipe with a spiral weld welded by automatic submerged arc welding process. There are more than one inner and outer welds. (This type of steel pipe is often called spiral welded pipe.)
