Stainless Steel Pipe Tube Low temperature performance
Variation of performance of stainless steel tube under low temperature
Stainless steel pipe welding production process:
Raw materials - slitting - welding pipe - repair - polishing - inspection (printing) - packaging - shipping (warehousing) (decorative pipe)
Raw materials - slitting - welding pipe - heat treatment - correction - straightening - repair - pickling - water pressure test - inspection (printing) - packaging - shipping (warehousing) (Pipe for piping industrial pipe)
Stainless steel pipe welding low temperature performance
1. Low temperature embrittlement --- In low temperature environment, the deformation energy is small. In low temperature environment, the elongation and the decrease of the shrinkage of the section are called low temperature embrittlement. And more in the ferrite series of body-centered cubic tissue.
2. Low temperature processing --- martensitic stainless steel tube from the austenitizing temperature quenching and then cooled to very low temperature, in order to promote the martensite quenching method. Suitable for easy production of residual austenitic stainless steel.
Stainless steel tube at low temperatures, resistance, linear expansion coefficient, thermal conductivity, mass heat and magnetic properties will change greatly. Resistance, the linear expansion coefficient decreases at low temperature; thermal conductivity, mass heat capacity decreases drastically at low temperatures; Young's modulus (longitudinal modulus) increases at the same time as the temperature decreases. Since the austenitic stainless steel tube has a Ms point (martensitic metamorphic starting temperature or martensite formation temperature) of a low temperature (Subzreo temperature), martensite can be generated while remaining below the Ms point. At low temperatures, the formation of martensite, so that the representative of the series of stainless steel steel SUS304 (18Cr-8Ni) at room temperature is non-magnetic, and in low temperature environment into a magnetic.
On the low temperature state, ferritic stainless steel pipe like carbon steel as low temperature brittleness, and austenitic steel is not present. So ferritic or martensitic stainless steel produces low temperature embrittlement and austenitic stainless steel or nickel based alloys do not show low temperature brittleness. The SUS410 (13Cr) and SUS430 (18Cr) of the ferrite stainless steel tube show a sharp drop in the impact value at a low temperature. Therefore, when used in a low temperature, it is necessary to pay special attention. As a method for improving the impact toughness of ferrite series stainless steel pipes, a high purification process can be considered. By controlling the C and N levels, the brittle temperature is improved in the range of -50 ° C to -100 ° C, it is possible to use it for refrigeration-related engineering. In recent years, SUS430LX (18Cr-Ti, Nb-LC) and SUS436L (18Cr-Mo-Ti, Nb-LC)