Piling Pipe is widely used in coastal, river, lake area. Offshore deepwater terminal project in the country have also been large-scale construction in coastal areas, and as a major deep-water dock pile bearing capacity, generally use the large diameter spiral weld pipe, in addition, bridges, roads, high-rise building needs piling pipe etc.

Post weld heat treatment can eliminate residual stress, prevent deformation, improve the performance of base metal and welded components, soften heat affected zone, increase weld ductility, improve toughness, discharge harmful hydrogen, improve creep performance and fatigue strength.

Steel pipe concrete structure is a novel composite structure made of concrete filled steel tube formed. Because steel concrete structure to more effectively play two materials steel and concrete respective advantages, while overcoming the disadvantages of steel structures is prone to local buckling.

Using the appropriate lubricant for stainless steel drawing had a significant effect. A layer of lubricant can have a certain toughness and elongation of the film between the convex and concave mold is formed, which is conducive to the stainless steel deep drawing.

Spiral pipe duct is the low carbon steel or low-alloy structural steel strip at a certain helix angle (called molding angle) rolled into a tube, and the tube is made of welded joints, which can be used to narrow band production of large diameter steel pipe.

Welding stress refers to the stress generated during welding of welded parts, the internal stress generated during welding and the change of weldment shape and size. The uneven temperature field, local plastic deformation and the resulting organization with different specific volume during welding are the root causes of welding stress and deformation.

Straight seam steel pipe is a practical steel pipe, which has been widely used in construction facilities of small and medium-sized construction sites. Not only that, straight seam steel pipes are often used in mining, power, construction and various piping systems, which is one of the important industries today

In recent years, most oil and gas pipelines in the world require the use of straight seam welded pipes. Canada and other western developed countries improve the process of spiral welded pipe, such as pre-welding, precision welding, multi-wire welding and mechanical expansion, etc., are designed with reference to the technology of longitudinal submerged arc welded pipe, which reflects the advanced nature of longitudinal welded pipe control technology and superiority. Specifically:

1.Cause (1) The rigidity of the work piece is uneven or small, and the shrinkage after welding is inconsistent. (2) Uneven arrangement of welds will lead to uneven shrinkage, and the shrinkage deformation of multiple welds is large. (3) Improper operation, no symmetrical layering, intermittent welding, inconsistent welding speed, current and direction, resulting in inconsistent deformation of machined parts. (4) The bite is too large during welding, resulting in stress concentration and large deformation. (5) Uneven welding results in deformation when stress concentration is released.

Generally, we call finger-welded pipes with an outer diameter greater than 500mm or more as large-diameter straight-seam steel pipes. Large-diameter straight-seam steel pipes are the best choice for large-scale pipeline projects, water and gas transmission projects, and urban pipe network construction.