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Causes of Pits on the Surface of Seamless Steel Pipes

Date:2021-05-25    keywords:pits, seamless steel pipes
The surface problem of seamless steel pipes is the most common one in the process of purchasing seamless steel pipes by all customers. We often encounter customers who conflict with downstream customers due to the surface pits of seamless steel pipes, and even cause refunds. Many customers vowed to guarantee surface quality problems when signing orders with upstream manufacturers. However, after delivery, they found surface pits, pits and other problems, and at this time customers will be in distress. Today, Permanent Steel Manufacturing Co.,Ltd will provide You analyze what causes the pits on the surface of the seamless steel pipe.

1. Piercing equipment

Many manufacturers choose unreasonable equipment for the perforation furnace. The shorter perforation furnace prevents the round steel from being evenly heated, resulting in higher internal and external temperature deviations, affecting structural changes, and causing pitting and pits. PMC has a long perforated heating furnace. Due to its length, the round steel is fully heated and evenly heated to reduce the occurrence of pits.


seamless steel pipe


2. Head settings

Generally, manufacturers use low-quality plugs. The water sprayed from the plugs directly touches the inner and outer surfaces of the high-temperature steel pipe. The steel pipe encounters a large temperature difference, resulting in internal and external defects, namely, peeling or pits. PMC adopts a special custom-made head, and there will be no warping and pits.

3. Perforation temperature

In the perforation furnace equipment, environmental protection and temperature control are not emphasized. For different steel grade seamless pipes( astm a106 seamless), the temperature adaptability cannot be adjusted in time, which in turn changes the surface and internal structure of the steel grade, causing the phenomenon of warping and pits.

4. Pickling


Seamless steel pipes need to undergo a pickling process. If the time is not controlled well, it is easy to cause overacid problems, which is also the cause of surface pits. PMC has 15 years of experience to control the pickling time, which reduces the problem of overacidity of seamless steel pipes. PMC has a complete quality inspection system to achieve true root-to-root inspection to ensure that seamless steel pipes without surface pits are sent to customers.

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