High manganese austenitic steel has attracted increasing attention for its application in liquefied natural gas storage tank materials due to its excellent ductility and low cost. This paper presents an overview of the research progress of high manganese austenitic steel in recent years. As a structural material used at a low temperature environment, high manganese steel should not only have certain strength, but also good toughness to prevent brittle fracture at a low temperature. In this work, factors affecting mechanical properties of high manganese steel are discussed, possible reasons for the deterioration of low-temperature properties are analyzed, and the strengthening and toughening mechanisms of materials are elaborated, which may be beneficial to improve properties of high manganese austenitic steel.

The effect of copper (Cu) on hot-rolled 301 austenitic stainless steel (ASS) was studied by observing the microstructures and testing the electrochemical corrosion resistance properties. The results showed that, with the increase in Cu content, the size of shear zones in 301 ASS decreased, and the number increased, which increased the uniformity of the microstructure macroscopically. The presence of Cu decreased the stacking fault energy of 301 ASS at elevated temperatures. Meanwhile, the amount of chromium (Cr) carbides decreased gradually with the increase in Cu content, which implies that the solid solution of Cu in hot-rolled 301 stainless steel promotes the solid solution of Cr and C in the steel, which is conducive to the formation of Cr-rich passivation films. As a result, the corrosion resistance of hot rolled Cu-bearing 301 stainless steel is improved, with both lower corrosion current density (I_corr) and passivation current (I_pass), and more positive corrosion potentials (E_corr) and passivation potential (E_p), even though it does not show a higher pitting resistance. As Cu content in the steel was increased from 0.4% to 1.1%, the corrosion resistance was not further improved.

With the introduction of O₂ during oil and gas production, the erosion-corrosion rate of tubing steels increases; the objective of this report is to explore the reason for this. Erosion–corrosion experiments were performed in environments of CO₂ and CO₂–O₂, respectively. Macrographs, microstructures, and the compositions of erosion-corrosion scales were investigated using a digital camera, scanning electron microscope (SEM), Kevex-SuperDry energy spectrometer (EDS) and X-ray diffraction (XRD). The results show that the erosion-corrosion products are composed of large FeCO₃ particles and some amorphous product in the CO₂ environment, while they are made up of FeCO₃, Fe₂O₃, Fe₃O₄, and bits of amorphous product in the CO₂–O₂ environment. The interface between erosion-corrosion scales and the substrate of 3Cr steel is smooth, and Cr enrichment obviously exists in the erosion-corrosion products in the CO₂ condition. However, the erosion-corrosion scale is loose and porous with little Cr enrichment in the CO₂–O₂ environment, which makes the protectiveness of the erosion–corrosion scale weak, and pitting corrosion occurs. The addition of O₂ may destroy the protective FeCO₃ scale and Cr enrichment in the erosion-corrosion scale, which may be the main reason for the decline in the level of protectiveness of the erosion-corrosion scale, making it weak in terms of preventing the corrosive medium from diffusing to the substrate.

Compression tests and metallographic observation were conducted to investigate the effect of temperature (400 °C–1100 °C), strain rate (0.001–10 s⁻¹) and chromium content (0.21–5.44 wt.%) on the flow behavior of high manganese steels for cryogenic application. The results showed that the flow stress reduced with increased temperature and decreased strain rate. The effect of chromium content on the flow stress of steels was not linear. The lowest flow stress was got when the content of chromium was 1.53 wt.%. The influence of strain rate and temperature was obvious while that of chromium content was minor. The maximum flow stress decreased 538 MPa-571 MPa when the temperature rised from 400 °C to 1100 °C at the strain rate 10 s⁻¹. It ascended 146 MPa-149 MPa when the strain rate increased from 0.001 s⁻¹ to 10 s⁻¹ at 400 °C. However, the effect of chromium content on the maximum flow stress of steels did not exceed 50 MPa at tested temperatures and strain rates. Dynamic recrystallization (DRX) was observed for all tested steels at 1100 °C. Higher temperatures and lower strain rates seemed to promote DRX. The true strain required for DRX was the largest when the chromium content in steels was 1.53 wt.%. It delayed the occurrence of DRX.

Antioxidant properties of several phenolic compounds in lubricants were investigated by quantum mechanical simulation. The reaction barrier of phenol, 2-tert-butylphenol and 2,6-di-tert-butylphenol with the alkoxy free radical generated by lubricants oxidation, the bond dissociation energy of O-H in them, and the energy difference from the HOMO to the LUMO of them were calculated. The reaction activity of phenoxy free radicals formed after hydrogen supply reaction was compared. The results showed that the hydrogen supply capacity of phenolic compounds decreased, while the reaction energy barrier of phenoxy free radicals with lubricants increased obviously with the increase of substituents on benzene ring. As the number of ortho substituents rise, the bond dissociation energy of O-H in phenolic compounds and the energy difference from the HOMO to the LUMO of them decreased slowly. The antioxidant properties of phenolic compounds in lubricants was related not only to the O-H bond dissociation energy and the energy difference from the HOMO to the LUMO of them, but also to steric hindrance in phenolic antioxidants.