An Gyubaek, Hong Seunglae, Park Jeongung, Han Ilwook
Department of Naval Architecture & Ocean Engineering, Chosun University, Gwangju, 61452, Republic of Korea.
Department of Civil Engineering, Chosun University, Gwangju, 61452, Republic of Korea.
J Nanosci Nanotechnol. 2021 Sep 1;21(9):4921-4925. doi: 10.1166/jnn.2021.19251.
The high manganese steel was developed to improve the fracture toughness and safety at cryogenic temperatures, the austenite structure was formed by increasing the manganese (Mn) content. The developed weld high manganese steel was alloyed with austenite stabilizing elements (e.g., C, Mn, and Ni) for cryogenic toughness and fluxes contained less than 10% of acidic slag formers such as rutile (TiO₂) and silica (SiO₂). This paper describes the work carried out to enhance the fracture toughness of Mn contents in an economical way by means of increase of manganese up to 23% instead of using nickel (Ni) which has unique element to improve fracture toughness especially at cryogenic steel. The new cryogenic steels should be carefully evaluated in terms of safety for application in real structures including LNG ships. In this study, the fracture toughness performance was evaluated for recently developed cryogenic steels (high-Mn steels), especially the crack tip opening displacement (CTOD) parameter was evaluated using the prediction formula proposed by conventional equation. The CTOD value was investigated the effect of microstructure and mechanical properties of Fe-C-Mn and Fe-C-Mn-Ni high manganese steel, it was revealed that the e-martesnsite phase formed in high manganese steel of 0.2C-20Mn and 0.4C-20Mn as a result of a low stability of austenite upon strain-induced phase transformation.
开发高锰钢是为了提高其在低温下的断裂韧性和安全性，通过增加锰（Mn）含量形成奥氏体组织。开发的焊接高锰钢与奥氏体稳定元素（如C、Mn和Ni）合金化以提高低温韧性，并且焊剂中酸性造渣剂（如金红石（TiO₂）和二氧化硅（SiO₂））的含量低于10%。本文描述了通过将锰含量提高到23%而不是使用镍（Ni）来以经济的方式提高Mn含量的断裂韧性所开展的工作，镍是一种独特的元素，尤其能提高低温钢的断裂韧性。新的低温钢在应用于包括液化天然气船在内的实际结构时，应从安全性方面进行仔细评估。在本研究中，对最近开发的低温钢（高锰钢）的断裂韧性性能进行了评估，特别是使用传统公式提出的预测公式对裂纹尖端张开位移（CTOD）参数进行了评估。研究了CTOD值对Fe-C-Mn和Fe-C-Mn-Ni高锰钢的微观结构和力学性能的影响，结果表明，由于应变诱导相变时奥氏体稳定性较低，在0.2C-20Mn和0.4C-20Mn的高锰钢中形成了e-马氏体相。
