Seamless steel pipes are widely used in various fields, but how to distinguish their quality? Here are suggestions offered by Landee Pipe Company.
1. Fake seamless steel pipes are easily to have puckers. Puckers referring to all folding lines on the surface of pipes, and the defects are usually longitudinally throughout the entire product. The primary reason for puckers is that manufactures are blindly pursued for high efficiency via wrong technique that cause ear and produce folds in next procedure. The folded pipes are easily to crack and the strength is also greatly decreased.
2.The fake pipes generally have pitting surface. Grooves with serious abrasion were the major reason for irregular and uneven defects on pipes' surface. Some manufactures just focusing on profits and often make excessive the groove rolling.
3. The surface of fake pipes is easily tended to produce scars. There are two reasons for scars. Firstly, the fake pipes were made of uneven material with too many impurities; secondly, the shoddy equipment is easy to stick steel, when some impurities get into the machine, will leave scars on pipes' surface.
4. The surface of fake pipes is apt to have cracks. The raw material for fake seamless steel pipes is poriferous adobe, due to thermal stress in cooling, the adobe will have fractures and after rolling they formed cracks.
5. Fake pipes are prone to be scratched. The fake pipe factories were poorly equipped, and pipes are easily to have burrs therefore scratching the surface of seamless steel pipes. Also, deep scratch will seriously reduce the intensity of seamless steel pipes.
6. The surface of fake pipes is without metallic luster, generally having similar color with iron. Major reason is the rolling temperature is not standard. Their temperature was measured manually rather than mechanically, therefore these pipes cannot have austenite region rolling, thus the performance can not reach the standard.
7. The cross-section of fake pipes is oval. In order to save material, some manufactures were purposely enlarging the rolling reduction which will result the declining intensity and can not meet requirements of dimensions.
8.Fake seamless pipes have larger diameter inaccuracies. There are three reasons contribute to this phenomenon: firstly, unstable steel temperature; secondly, uneven steel composition; thirdly, lagging device and larger bounce of rolling mill. All these reasons have resulted larger internal diameter, therefore steel pipes can not have even stress and easily to be fractured.
9. Fake seamless steel pipes generally do not have standard trademarks and printings.
10. The longitudinal rebar of fake steel pipes often have wave shape.
11. Fake seamless pipe manufactures have relatively loose packages.