Q345B spiral tube is prone to cracks in thermal treatment cooling. So, what aspects should spiral pipe manufacturers pay attention to the emergence of cracks in the production process?
1. After quenching, you should recover in time. Many spiral steel pipes are not produced during the quenching and cooling process, but after taking out the quenching medium, it appears after a period of time, the so -called timeliness crack. This is due to a large quenching stress. If the fire treatment is performed immediately after quenching, it can effectively prevent the occurrence of timely cracks.
2. The self -ignition should be used to use the quenching waste heat for the cracks.
3. Use lower quenching temperature and short insulation time. For high -alloy steel, the spiral steel pipes are poorly conducted by high alloy steel, so they should be fully heated (one or many times).
4. For parts that are easy to quench (such as threaded holes, edges, grooves, etc.), you must use stone cotton ropes to plug or wrap it with iron. Causes the spiral steel pipe.
5. Choose a medium that is slowly cooling and use oil -cooled spiral steel pipes to avoid cold in the water; master the time when the cooling medium is used to cool to the vicinity of the spiral steel pipe. For the occurrence, a pyrine concentration or nitrate saline solution can be used as the cooling medium, which can make the complex workpiece from the risk of quenching cracks.
