Defect Analysis of High-precision Cold-rolled Seamless Steel Pipe

Analysis of quality defects on the inner and outer surface of high-precision cold-rolled(cold drawn) seamless steel pipe:

Cold rolled seamless steel pipes have the characteristics of no oxide layer on the inner and outer walls, no leakage under high pressure, high precision, high finish, no deformation when cold bending, no cracks in flaring and flattening, and anti-rust treatment on the surface. They are mainly used for mechanical structures, Hydraulic equipment and pneumatic or hydraulic components of automobiles and motorcycles.

The industrial control of the production of cold-rolled seamless steel pipes includes mold design, annealing, pickling, lubrication and other conditions. At the same time, it is necessary to do a good job in capillary quality inspection and renovation.

Cold rolled seamless steel pipes are prone to some defects in the production process, which will directly lead to the performance requirements of cold rolled seamless steel pipes, and even produce certain risks during use, such as: cracks, internal Folding, external folding, crushing, separation, scarring, concave pulling, convex hull, etc. Therefore, these defects must be avoided in the production process of cold rolled seamless steel pipes.

cause:

• Due to surface defects or internal defects of cold rolled seamless steel tube blanks.
• Produced in the production process, such as incorrect design of rolling process parameters, unsmooth mold surface, poor lubrication conditions, unreasonable pass design and adjustment.
• In the process of heating, rolling, heat treatment and straightening of the tube blank (cold drawn seamless steel pipe), if the heating temperature is not properly controlled, the deformation is uneven, the heating and cooling rate is unreasonable or the straightening deformation is too large. Residual stress may also cause surface cracks in cold rolled seamless steel pipes.

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There are many reasons for the defects of cold rolled seamless steel pipes in the production process, which have a very large impact on the performance of cold rolled seamless steel pipes. Therefore, cold rolled seamless steel pipe manufacturers must avoid these situations during the production process.

High-precision cold-rolled precision steel pipe is a new type of high-tech energy-saving product., The popularization and application of high-precision cold-rolled precision steel pipes can save steel, improve processing efficiency, and save energy. The so-called high-precision cold-rolled seamless steel pipe refers to strict inner and outer diameter dimensional accuracy (tolerance range), inner and outer surface smoothness, roundness, straightness The characteristics of good temperature and uniform wall thickness.

Tips: ASTM A53 covers seamless and welded steel pipe with nominal wall thickness. The surface condition is usually black and hot-dipped galvanized. ASTM A53 is produced mainly for pressure and mechanical applications, and is also used for transport of steam, water, gas line pipes.

In case ASTM A53 Grade B in ERW (electric resistance welded) pipe, the weld seam shall be done the heat treatment with a minimum 1000°F [540°C]. In this way the no untempered martensite remains.

In case ASTM A53 B pipe in cold expanded, then expansion should not exceed 1.5% of the required OD.

Steel pipe industry practitioners at Permanent Steel Manufacturing Co.,Ltd, knowledge enthusiasts