In the production of carbon steel (CS) seamless pipes, the cold treatment process is usually used to improve the strength and hardness of the material. The following is the general CS seamless pipe cold treatment process.
In the manufacturing process of CS seamless pipes, water quenching is a common quenching method used to rapidly cool seamless pipes to increase their hardness. This is usually part of a quenching and tempering process, where quenching is used to increase hardness and tempering is used to restore some toughness. It should be noted that water quenching can be performed immediately after the heating stage or before tempering. Process conditions for the entire quenching and tempering process, such as temperature and duration, will vary depending on the specific carbon steel alloy, seamless pipe size and application requirements.
Oil quenching is another quenching method for CS seamless pipes, which is usually used to rapidly cool seamless pipes to increase hardness. Compared to water quenching, oil quenching cools relatively slowly, reducing brittleness while still providing some hardness. As with water quenching, the process conditions for oil quenching, such as quenching temperature, quenching time and tempering conditions, will depend on the specific carbon steel alloy, seamless pipe size and application requirements. Quality control and compliance with relevant standards are important factors in ensuring that the oil quenching process is performed correctly.
In some special cases, CS seamless pipes may use salt quenching as the quenching method. Salt quenching typically involves the use of molten salt as the quenching medium, providing higher cooling rates than water or oil while avoiding brittleness issues caused by cooling too quickly. One advantage of salt quenching is that it provides more uniform cooling, reducing the risk of internal stress and deformation. However, it is important to note that salt quenching may involve high-temperature molten salt, so appropriate safety measures must be taken.
The specific CS seamless pipe cold treatment process and parameters may vary depending on the composition of the steel, its use, and the standards or specifications that must be followed. Before implementing any cold treatment process, material properties, welding procedures, and other relevant factors must be carefully analyzed to determine the most suitable cold treatment process for the specific application.