Solution temperature is mainly determined by chemical composition.Generally speaking,there are many kinds of alloying elements,and the solution temperature should be increased accordingly.Especially for steels with high content of manganese,molybdenum,nickel and silicon,the softening effect can be achieved only by increasing the solution temperature and making it fully dissolved.However,the stabilized steels,such as 321 stainless steel pipe,its carbides of stabilized elements are fully dissolved in austenite at high solution temperature,and precipitate at grain boundaries in the form of Cr23C6 during subsequent cooling, resulting in intergranular corrosion.In order to keep the carbides of stabilized elements (TiC and NbC) undissolved and insoluble,the lower limit solution temperature is generally adopted.
ASTM A312 TP316L seamless steel pipes
For stainless steel seamless pipes,the three elements of solution treatment are temperature,holding time and cooling rate.What is the effect of solution treatment of stainless steel seamless pipes?
Firstly,it can make the structure and composition of stainless steel seamless pipes uniform,especially important for raw materials.Because the rolling temperature of each section of hot-rolled tubes and cooling rate are different,which results in the structure inconsistency.At high temperature,atomic activity intensifies,phase dissolves,chemical composition tends to be uniform,and uniform single-phase structure can be obtained after rapid cooling.
Secondly,solution treatment can eliminate work hardening to facilitate the continuation of cold working.After solution treatment,the distorted lattice is restored,the elongated and broken grains are recrystallized,the internal stress is eliminated,the tensile strength of steel wire decreases, and the elongation increases.
What’s more,it can restore the inherent corrosion resistance of stainless steel pipes.The corrosion resistance of stainless steel pipes decreases due to carbide precipitation and lattice defects caused by cold working.The corrosion resistance of stainless steel seamless tubes can restore to the optimum state after solution treatment.
Haihao Group manufacture stainless steel seamless steel in materials ASTM A312 TP304,TP304L,TP316,TP316L,TP321,TP347,etc.If you want to know more about our pipeline products(seamless steel pipes,welded steel pipes,butt welding pipe fittings,forged pipe fittings,forged flanges),please email us:sales@haihaogroup.com
