Purpose

Effect of grain size on degree of sensitization (DOS) was been evaluated in Nickel free steel. Manganese and nitrogen contained alloy is a Ni-free austenitic stainless steels (ASS) having type 202 grade. The main purpose of this investigation is to find the effect of recrystallization on the DOS of stainless steel after the thermo-mechanical processing (cold work and thermal aging).

Design/methodology/approach

In the present investigation, the deformation of 202 grade analyzed using X-ray diffraction (XRD) and microstructural testing. Optical microstructure of Ni-free ASS has been done for cold worked samples with thermally aged at 900°C_6 h. Double loop electrochemical potentiodynamic reactivation test used for findings of degree of sensitization.

Findings

Ni-free ASS appears to be deformed more rapidly due to its higher stacking fault energy which gave results in rapid transformation from strain induced martensite to austenite in form of recrystallized grains, i.e. it concluded that as cold work percentage increases more rapidly recrystallization occurs. XRD results also indicate that more fraction of martensite formed as percentage of CW increases but as thermal aging reverted those all martensite to austenite. So investigation gives the conclusion which suggests that with high deformation at higher temperature and duration gives very less DOS.

Originality/value

Various literatures available for 300 series steel related to the effect of cold work on mechanical properties and sensitization mechanism. However, no one has investigated the effect of recrystallization through thermomechanical processing on the sensitization of nickel-free steel.

中文翻译：

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再结晶对无镍奥氏体不锈钢敏化度的影响

目的

在无镍钢中评估晶粒尺寸对敏化度 (DOS) 的影响。含锰和氮的合金是一种 202 型无镍奥氏体不锈钢 (ASS)。本研究的主要目的是发现再结晶对热机械加工（冷加工和热时效）后不锈钢的 DOS 的影响。

设计/方法/方法

在目前的调查中，使用 X 射线衍射 (XRD) 和微观结构测试分析了 202 级的变形。对冷加工样品在 900°C_6 h 下热时效进行了无 Ni ASS 的光学显微组织。双回路电化学动电位再活化试验用于检测致敏程度。

发现

由于其较高的堆垛层错能，无镍 ASS 似乎变形更快，这导致从应变诱发马氏体快速转变为再结晶晶粒形式的奥氏体，即得出结论，随着冷加工百分比的增加，再结晶发生的速度更快。XRD 结果还表明，随着 CW 百分比的增加，更多的马氏体形成，但随着热老化，所有马氏体都恢复为奥氏体。因此，调查得出的结论表明，在较高温度和持续时间下高变形会产生非常少的 DOS。

原创性/价值

关于冷加工对机械性能和敏化机制的影响，有关 300 系列钢的各种文献。然而，没有人研究过热机械加工再结晶对无镍钢敏化的影响。