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2019-07

What is the effect of solution treatment on stainless steel seamless pipes

The solution temperature is primarily determined based on chemical composition. Generally speaking, for trademarks with a wide variety and high content of alloy elements, the solution temperature should be improved accordingly.

The solution temperature is primarily determined based on chemical composition. Generally speaking, for trademarks with a wide variety and high content of alloy elements, the solution temperature should be improved accordingly. Especially for steels with high manganese, molybdenum, nickel, and silicon contents, only by improving the solution temperature and making them fully soluble can the softening effect be achieved. However, in stabilized steels, such as 321 stainless steel tubes, when the solution temperature is high, the carbides of the stabilized elements are fully dissolved in austenite, and during subsequent cooling, they will separate out at the grain boundaries in the form of Cr23C6, forming intergranular corrosion. In order to prevent the carbide (TiC and NbC) of the stabilizing element from differentiating and solubilizing, a lower limit solution temperature is usually selected.

For stainless steel seamless pipes, the three elements of solution treatment are temperature, holding time, and cooling speed. What are the effects of solution treatment on stainless steel seamless pipes?

1: Making the arrangement and composition of stainless steel seamless pipes uniform is particularly important for materials, as the rolling temperature and cooling speed of each section of hot rolled pipe are different, resulting in inconsistent arrangement and structure. Atomic activity increases at high temperatures, σ The phase dissolves, the chemical composition tends to be uniform, and after rapid cooling, a uniform single-phase arrangement is obtained.

2: Eliminate work hardening to facilitate continuous cold working. Through solution treatment, twisted lattice is rehabilitated, elongated and broken grains are de novo crystallized, internal stress is eliminated, tensile strength of steel wire is reduced, and elongation is increased.

3: Rehabilitation of the inherent corrosion resistance function of stainless steel tubes. Due to the carbide separation and lattice defects formed during cold processing, the corrosion resistance function of stainless steel pipes is reduced. After solution treatment, the corrosion resistance function of stainless steel seamless pipes recovers to the best condition.