What are the defects of the treatment process of spiral steel pipe

Spiral steel pipe plays a very important role in our life. The following editor will introduce the common defects of each process according to the heat treatment process of spiral steel pipe.

1. Defects in the heating process. For the heating process, heat treatment heating equipment and heating medium must be selected. What appears or easily occurs here is that the surface of the part will be affected by the oxidizing heating medium. The heating temperature exceeds the process requirements, and the austenite crystal If the grains are too coarse, or even the grain boundaries melt, it will seriously affect the appearance and internal quality of the parts. Therefore, in the actual process, feasible measures should be taken for the analysis of such defects.
2. When quenching small-diameter spiral tubes, the defective parts produced are cooled after heating and austenite homogenization to obtain the required structural and mechanical properties. At this time, it is necessary to select the ideal according to the material and specific hardness of the parts. Cooling medium, the ideal cooling medium is rapid cooling at high temperature and slow cooling at low temperature (3o0°C).
3. Quench the defective parts produced during the tempering process to obtain a high-hardness quenched martensite structure or a slightly lower hardness lower bainite structure. However, the structure at this time is unstable and highly brittle. During production When used, it must be tempered to obtain the required structure and properties.
4. The above surface quenching defect is the overall heat treatment of the part, so the required hardness and requirements can be obtained both inside and outside the part. The surface hardening treatment is only used for surface hardening of the part, and the core is still in a structural state before treatment, so surface quenching Temperature, heating time, hardened layer depth, etc. will all affect the heat treatment deformation and cracking, hardness level and service life of the parts.
5. Defects of chemical heat treatment of small-diameter spiral tubes. Chemical heat treatment of spiral tubes is a heat treatment process in which metal or non-metal atoms penetrate the surface of parts to obtain required surface properties (such as high wear). This process gives the parts dual functions and Therefore, we must pay full attention to the chemical heat treatment of parts, otherwise the significance of chemical heat treatment of parts will be completely lost. The heat treatment of parts should be safe, economical and practical, and at the same time, a clean and quiet working environment should be created.
The correct heat treatment process is the premise and foundation to ensure the qualified heat treatment quality of parts. Once the above quality problems are found, they can be solved from people, machines, materials, methods, links and inspections. Through analysis and judgment, the root cause of defects can be found.