In the process of API 5L GR.B steel pipe forming, advanced production technology is used to ensure that the wall thickness of the steel pipe is uniform and the inner and outer surfaces are smooth. The heat treatment link controls parameters such as heating temperature and cooling rate to make the steel pipe obtain ideal organization and performance. Finally, the steel pipe is comprehensively inspected by means of non-destructive testing to ensure that the product quality meets the standard requirements.
The production process of API 5L GR.B carbon steel line pipe mainly includes smelting, continuous casting, rolling, sizing and other links. In the smelting process, electric furnace or converter smelting is used to ensure the quality of molten steel; in the continuous casting process, continuous casting billet process is used to improve the yield rate; in the rolling process, controlled rolling and controlled cooling process is used to improve the strength and toughness of the steel pipe; in the sizing process, high-pressure water descaling and straightening machine are used to ensure the surface quality and precision of the steel pipe.
In addition, the pipe must undergo various heat treatments such as normalizing, quenching, and tempering to obtain the required microstructure and mechanical properties. These heat treatments can affect the final chemical composition by promoting the formation of certain phases and precipitates.
API 5L Grade B ERW Pipe Tolerance
| OD Tolerance | WT Tolerance | ||||
|---|---|---|---|---|---|
| A, B | X42 ~ X70 | ||||
| D<60.3milimeter | +0.41/-0.40milimeter | D<73milimeter | +20%/-12.5% | D<73milimeter | +15%/-12.5% |
| D>=60.3milimeter | +0.75/-0.40milimeter | D>=73milimeter | +15%/-12.5% | D>=73milimeter | +15%/-12.5% |
API 5L GR.B seamless pipe
