Quality inspection of thick-walled seamless pipes

Thick-walled steel pipe refers to a steel pipe whose outer diameter to wall thickness ratio is less than 20. Common products include ASTM A106 seamless steel pipe, ASTM A53, etc. Mainly used as petroleum geological drilling pipes, petrochemical cracking pipes, boiler pipes, bearing pipes and high-precision structural pipes for automobiles, tractors, aviation, etc. Thick-walled seamless steel pipes have many quality requirements when used in some industries, so how should we identify the quality of thick-walled seamless pipes? Here are several methods.

1. High-quality thick-walled seamless pipes have uniform composition, high cold shear tonnage, and smooth and neat end faces of the cutting heads. However, due to the poor material, the end surface of the cutting head is often uneven and has no metallic luster. Moreover, due to fewer incisions made by fake and inferior material manufacturers, big ears will appear on the head and tail.

2. Inferior thick-walled seamless pipes have no metallic luster and are light red or similar to pig iron. There are two reasons for the production of steel billets. One is the irregular rolling temperature of inferior materials, and the other is visual inspection of steel temperature. When rolled according to the specified austenite area, the performance of thick-walled seamless pipes will naturally not meet the standards.

3. The material of fake and inferior thick-walled seamless pipes has many impurities, the steel density is low, and the dimensions are seriously out of tolerance. In the absence of vernier calipers, they can be weighed and inspected.

4. The cross-section of inferior thick-walled seamless pipes is oval because the manufacturer reduces the number of the first two passes of the finished roll in order to save materials. The strength of this steel bar is greatly reduced and inconsistent with steel bars. Standard dimensions.

5. The surface of inferior thick-walled seamless pipes is prone to scars.

There are two reasons:

① Inferior thick-walled seamless pipes have uneven materials and many impurities.

② The guide equipment of counterfeit and inferior material manufacturers is simple and easy to stick to steel. These impurities can easily leave scars after biting the roller.

6. The surface of inferior materials is prone to cracks because the blank is made of adobe. There are many pores on the adobe. The adobe will crack due to thermal stress during the cooling process, and cracks will occur after rolling.

The above are the six ways we can distinguish seamlessness in production and life. Only by understanding and understanding these can we choose pipes with good quality and reasonable price produced by good seamless pipe manufacturers.

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