Austenitic stainless steel tube
through the solution treatment to soften, the general stainless steel tube
heated to 950 ~ 1150 ℃ or so, for some time, so that the carbide and a variety of alloying elements fully dissolved in austenite, and then quickly quenched water cooling, carbon and other alloying elements too late to precipitate, access to pure austenite, known as the solution treatment. Stainless steel tube solution treatment of the role of 3 points.
Because the hot rolling wire sections of the rolling temperature and cooling rate is not the same, resulting in inconsistent organizational structure. At high temperatures, the atomic activity is aggravated, the σ phase is dissolved, the chemical composition of the stainless steel tube tends to be uniform, and the uniform single phase structure is obtained after rapid cooling.
When the solution temperature is high, the carbides of the stabilized elements are fully dissolved in the austenite, and in the subsequent cooling, the grain boundary is precipitated in the form of Cr23C6, resulting in intergranular corrosion. In order to stabilize the elements of the stainless steel tube carbide (TiC and NbC) does not decompose, not solid solution, generally use the lower solution temperature.