Steel sheet piles and soil retaining structures are less rigid than underground diaphragm walls and mixing piles. If the design and construction are not taken seriously, the foundation pit (trough) will become unstable, seepage and leakage of slurry and mud will cause the surrounding foundation soil to settle, and cause damage to surrounding buildings and pipelines.

Steel pipes (seamless steel pipes, welded steel pipes, etc.) can be divided into three types of damage during shipping: rust damage, physical damage, and corrosion

Stress relief annealing is a process of heating steel pipes (seamless pipes, welded steel pipes) to an appropriate temperature, and gradually cooling down after holding for a certain period of time. Its purpose is to remove the residual stress of the steel pipe due to machining, deformation processing, casting, forging, heat treatment and welding.

Among the standards for seamless steel pipes and welded steel pipes, Brinell hardness is the most widely used, and the indentation diameter is often used to express the hardness of the material, which is intuitive and convenient. But it is not suitable for steel pipes of harder or thinner steel.

Both stainless steel seamless pipes and stainless steel welded pipes can be cold processed --- cold rolling and cold drawing to meet higher requirements for cold processed products.

The main production process layout and equipment composition of row-roll forming The row-roll forming machine is a major component of the welded pipe production line. It is the core of production and the key equipment on the production line, which is responsible for bending flat steel strips into round tube billets.