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| The role of stainless steel solution treatment |
| Date2009-09-16
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Austenitic stainless steel by solution heat treatment to soften, generally wire heated to about 950 ~ 1150 ℃, holding time, so that the full carbon and various alloying elements dissolved in austenite evenly, and then quickly quenching water cooling, carbon and other alloying elements precipitate too late to obtain a pure austenite, called solution heat treatment.
⑴ to wire the organization and composition of uniform, and this material is particularly important because the various sections of hot-rolled wire rod rolling temperature and cooling rate not the same, resulting in inconsistencies in the organizational structure. Intensified at a high temperature atomic, σ-phase dissolved, the chemical composition tends to uniformity, after rapid cooling to obtain a homogeneous single-phase compositions.
⑵ to eliminate work-hardening, in order to facilitate continued cold. By solution treatment, contorted lattice recovery, elongation and fragmentation of the grain re-crystallization of the elimination of internal stress, tensile strength steel wire decreased elongation rates.
⑶ to restore the inherent corrosion resistance of stainless steel. As the cold caused by carbide precipitation, lattice defects, so that the corrosion resistance of stainless steel decreased. Corrosion resistance of steel after solution treatment return to top condition.
For the stainless steel, the solution treatment of the three elements of temperature, holding time and cooling rate.
Solution temperature determined based mainly on chemical composition. In general, many kinds of alloying elements, high levels of grades, the solution temperature should be increased accordingly. In particular, manganese, molybdenum, nickel, steel with high silicon content, only the increase of solution temperature to fully dissolve in order to achieve softening effect. However, stabilization of steel, such as 1Cr18Ni9Ti, solid solution at high temperature stabilization of the element carbon fully dissolved in austenite, in the subsequent cooling in the form will Cr23C6 precipitate at the grain boundaries, causing intergranular corrosion. In order to stabilize the element carbon (TiC, and NbC) are not broken down, non-solid solution, generally use lower solution temperature.
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