Questions regarding the solution treatment and stabilization treatment of stainless steel

Check the stainless steel pipe standards for temperature specifications. . . Such as GB/T12771 and GB/T14976. . Stabilization treatment containing Ti and Nb. .

The heating temperature for solution treatment is generally high, ranging from 1050 to 1100°C, followed by rapid cooling to maintain the austenite in a solid-solved state at room temperature. The heating temperature can be adjusted appropriately according to the carbon content. The purpose of solution treatment is to fully dissolve the carbides and retain them in austenite at room temperature, thereby achieving a single-phase austenitic structure at room temperature and giving the steel the highest corrosion resistance. The stabilization annealing of 18-8 stainless steel typically involves heating to 850–880°C, holding at that temperature for 2–6 hours, followed by air cooling or furnace cooling. Ti, Nb, and C have a stronger affinity for it than Cr. Stabilization treatment involves heating stainless steel containing titanium and niobium to a certain temperature and then cooling it slowly; at this temperature, the chromium carbides dissolve completely in the austenite, while TiC and NbC dissolve only partially. During the cooling process, carbon in the steel reacts fully with titanium and niobium, resulting in the precipitation of stable TiC and NbC, without the formation of chromium carbides; this eliminates the tendency for intergranular corrosion in 18-8 austenitic stainless steel.