Thick wall welded steel pipe---the background of the introduction

Classification of thick-wall welded steel pipes：

Thick-wall welded steel pipes include straight seam welded steel pipe SAWL, spiral welded steel pipe SAWH, high frequency welded steel pipe ERW, and combined welded steel pipe COW. Thick-wall welded steel pipes usually refer to steel pipes with a thickness of 14mm or more. The SAWL production thickness of the longitudinally welded steel pipe is 8mm-80mm; Spiral welded steel pipe SAWH production thickness 5.5mm-30mm; The production thickness of high frequency welded steel pipe ERW is 0.8mm-24mm; The above four steel pipes are the most commonly used welded steel pipes in the industry. The similarities of these four products are: they can all implement the GB/T3091-2008 low-pressure fluid steel pipe standards. The difference is that the welding style is different, the pipe body vision is different, and the high Different standards and different industries are used.

The different welding styles of thick-walled steel pipes:

SAWL has only one weld on the pipe body (two are allowed when the diameter is greater than 914). Double-sided submerged arc welding is used for welding, and the welding wire is used as the welding filler. SAWH has only one spiral weld. Double-sided submerged arc welding is used when welding, and welding wire is used as welding filler. ERW is the pipe body with only one straight seam. The principle of high-frequency resistance is used when welding, so that the steel plate end is squeezed by external force by hot melt, and the base material is welded without welding wire. COW pipe body weld style can be straight seam, spiral seam, gas shielded welding and submerged arc welding are used for welding.

The visual difference of thick-walled steel pipe body:

SAWL is one or two straight welds, SAWH is spiral welds, ERW has one weld and no weld seam height, and COW gas shielded welds are not completely covered by submerged arc welds. The difference in the high standards of thick-walled steel pipes: SAWL high standard implementation: GB/T9711.1-1997, GB/T9711.2-1997, API 5L. SAWH high standard implementation: GB/T9711.1-1997, GB/T9711.2-1997, GB/T5037.

Industries for thick-wall welded steel pipes:

SAWL straight-joint thick-walled steel pipes are widely used in heavy steel structures, bridge piling, bridge structures, and long-distance oil and gas transportation. SAWH spiral thick-walled steel pipes are mostly used in low-pressure fluid water pipelines and high-pressure natural gas long-distance pipelines. ERW high-frequency welded steel pipes are mostly used in various industries, and the restriction is that the maximum wall thickness of high-frequency welded steel pipes can only be produced to 24mm. The application of electric resistance welded steel pipe in the steel pipe industry accounts for 60% of the steel pipe products worldwide. In addition, high-frequency thick-walled steel pipes are often used as raw materials for processing hot-expanded steel pipes and rectangular steel pipes.

Among the thick-wall welded steel pipes, the production of SAWL LSAW steel pipes is the most prominent. From the above data, it can be seen that the thickness of domestic LSAW steel pipes can be produced to 80mm, and the range of production specifications is wide, and the production efficiency is high. The standard is up to API. SAWL thick-wall steel pipes have been favored by large-scale steel structure projects and thick-wall welded steel pipe dealers at home and abroad!