First, thermomechanical treatment
High-temperature thermomechanical treatment can improve the yield ratio and elastic limit of spiral steel pipes. Improve the comprehensive mechanical properties, fatigue properties, and stress relaxation properties of spiral steel pipes. Reducing the tough-brittle transition temperature and tempering the brittleness of steel has the advantages of a simple process and energy saving. High-temperature thermomechanical treatment has a significant effect on spiral pipes. The specific process is heating temperature 920-950℃, hot rolling deformation 10%-30%, air cooling time 10-30 seconds, oil quenching; then ordinary tempering or high-temperature rapid tempering above 400℃.
Second, chemical heat treatment in the ferrite state
Chemical heat treatment in the ferrite state, such as nitriding, nitrocarburizing, etc., can significantly improve the surface hardness, wear resistance, corrosion resistance, residual compressive stress, and fatigue life of spiral pipes. The chemical heat treatment temperature is generally between 450 and 600℃. The quenched and tempered spiral pipe can be treated by combining chemical heat treatment and tempering. The chemical heat treatment temperature of the precipitation-hardened spiral pipe is the same as the precipitation-hardening temperature.
As the application of spiral steel pipes becomes more and more extensive, the requirements for the technology and product diversity of spiral steel pipes are also getting higher and higher.
Post time: Sep-11-2024