scholarly journals Recent Progress of Low and Medium-Carbon Advanced Martensitic Steels

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 652
Author(s):  
Koh-ichi Sugimoto
Keyword(s):  
Mechanical Properties ◽  
Fatigue Strength ◽  
Retained Austenite ◽  
Case Hardening ◽  
Martensitic Steels ◽  
Delayed Fracture ◽  
Medium Carbon ◽  
Warm Working ◽  
Hardening Process ◽  
Vacuum Carburization

This article introduces the microstructural and mechanical properties of low and medium-carbon advanced martensitic steels (AMSs) subjected to heat-treatment, hot- and warm- working, and/or case-hardening processes. The AMSs developed for sheet and wire rod products have a tensile strength higher than 1.5 GPa, good cold-formability, superior toughness and fatigue strength, and delayed fracture strength due to a mixture of martensite and retained austenite, compared with the conventional martensitic steels. In addition, the hot- and warm-stamping and forging contribute to enhance the mechanical properties of the AMSs due to grain refining and the improvement of retained austenite characteristics. The case-hardening process (fine particle peening and vacuum carburization) is effective to further increase the fatigue strength.

Microstructure and Mechanical Properties of a Nb-Microalloyed Medium Carbon Steel Treated by Quenching-Partitioning Process

2012 ◽  
Vol 531-532 ◽  
pp. 596-599
Author(s):  
Kai Zhang ◽  
Shang Wen Lu ◽  
Yao Hui Ou ◽  
Xiao Dong Wang ◽  
Ning Zhong
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Electron Microscope ◽  
Carbon Steel ◽  
Retained Austenite ◽  
High Strength ◽  
Medium Carbon Steel ◽  
Orientation Relationships ◽  
Medium Carbon ◽  
Microstructure And Mechanical Properties

The recently developed “quenching and partitioning” heat treatment and “quenching-partitioning-tempering” heat treatment are novel processing technologies, which are designed for achieving advanced high strength steels (AHSS) with combination of high strength and adequate ductility. In present study, a medium carbon steel containing Nb was subjected to the Q-P-T process, and both the microstructure and mechanical properties was studied. The experimental results show that the Nb-microalloyed steel demonstrates high tensile strength and relatively high elongation. The microstructure of the steel was investigated in terms of scanning electron microscope and transmission electron microscope, and the results indicate that the Q-P-T steel consist of fine martensite laths with dispersive carbide precipitates and the film-like interlath retained austenite. The orientation relationships between martensite and retained austenite is as well-known Kurdjurmov-Sachs relationship and Nishiyama-Wasserman relationship.

scholarly journals Influence of Iron Carbide on Mechanical Properties in High Silicon-added Medium-carbon Martensitic Steels

2020 ◽  
Vol 106 (3) ◽  
pp. 165-173
Author(s):  
Shinya Teramoto ◽  
Masahito Imura ◽  
Yuki Masuda ◽  
Toshinori Ishida ◽  
Masato Ohnuma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Iron Carbide ◽  
Martensitic Steels ◽  
Medium Carbon ◽  
High Silicon

scholarly journals Effects of Cr and Mo on Mechanical Properties of Hot-Forged Medium Carbon TRIP-Aided Bainitic Ferrite Steels

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1066 ◽  
Author(s):  
Koh-ichi Sugimoto ◽  
Sho-hei Sato ◽  
Junya Kobayashi ◽  
Ashok Kumar Srivastava
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Retained Austenite ◽  
Bainitic Ferrite ◽  
Ferrite Matrix ◽  
Total Elongation ◽  
Matrix Structure ◽  
Medium Carbon ◽  
Base Steel ◽  
Mo Additions

In this study, the effects of Cr and Mo additions on mechanical properties of hot-forged medium carbon TRIP-aided bainitic ferrite (TBF) steel were investigated. If 0.5%Cr was added to the base steel with a chemical composition of 0.4%C, 1.5%Si, 1.5%Mn, 0.5%Al, and 0.05%Nb in mass%, the developed steel achieved the best combination of strength and total elongation. The best combination of strength and impact toughness was attained by multiple additions of 0.5%Cr and 0.2%Mo to the base steel. The excellent combination of strength and impact toughness substantially exceeded those of quenched and tempered JIS-SCM420 and 440 steels, although it was as high as those of 0.2%C TBF steels with 1.0%Cr and 0.2%Mo. The good impact toughness was mainly caused by uniform fine bainitic ferrite matrix structure and a large amount of metastable retained austenite.

Designing, Processing and Isothermal Transformation of Al-Si Medium Carbon Ultrafine High Strength Bainitic Steel

2017 ◽  
Vol 380 ◽  
pp. 1-11
Author(s):  
Sherif Ali Abd El Rahman ◽  
Ahmed Shash ◽  
Mohamed K. El-Fawkhry ◽  
Ahmed Zaki Farahat ◽  
Taha Mattar
Keyword(s):  
Mechanical Properties ◽  
Carbon Steel ◽  
Retained Austenite ◽  
High Carbon Steel ◽  
Bainitic Ferrite ◽  
High Strength ◽  
Isothermal Transformation ◽  
High Carbon ◽  
Medium Carbon ◽  
The Stability

Medium-carbon, silicon-rich steels are commonly suggested to obtain a very fine bainitic microstructure at a low temperature slightly above Ms. Thereby, the resulted microstructure consists of slender bainitic-ferritic plates interwoven with retained austenite. The advanced strength and ductility package of this steel is much dependent on the fineness of bainitic ferrite, as well as the retained austenite phase. In this article, the aluminum to silicon ratio, and the isothermal transformation temperature have been adopted to obtain ultra-high strength high carbon steel. Optical and SEM investigation of the produced steels have been performed. XRD has been used to track the retained austenite development as a result of the change in the chemical composition of developed steels and heat treatment process. Mechanical properties in terms of hardness and microhardness of obtained phases and structure were investigated. Results show that the increment of aluminum to silicon ratio has a great effect in promoting the bainitic transformation, in tandem with improving the stability and the fineness of retained austenite. Such an advanced structure leads to enhancement in the whole mechanical properties of the high carbon steel.

Effect of Vanadium on Microstructure and Mechanical Properties of Air Cooled Medium Carbon High Silicon Bainite Steels

2011 ◽  
Vol 311-313 ◽  
pp. 931-935
Author(s):  
Jun Miao ◽  
Li Jun Wang ◽  
Chun Ming Liu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Retained Austenite ◽  
Silicon Steel ◽  
Alloyed Steel ◽  
Air Cooling ◽  
Medium Carbon ◽  
Transmission Electron ◽  
High Silicon Steel ◽  
High Silicon

The effect of vanadium on the bainite transformation of medium carbon high silicon steel during air cooling was studied by using Optical Microscopy (OM) and Transmission Electron Microscopy (TEM). The mechanical properties of the test steels subjected to heat treatment were measured by tensile, hardness and impact tests. The results showed that, through the same heat treatment process, the microstructure of the V-alloyed steel was comprised of Carbide-Free Bainite (CFB, bainite + retained austenite) and martensite while the microstructure of the V-free steel was composed of ferrite/pearlite, which made the V-alloyed steels exhibit superior combination of strength, hardness and toughness to the V-free steel, but the elongation of the V-alloyed steel was worse than that of the V-free steel somewhat. Vanadium was helpful for the transformation of bainite in the tested medium carbon high silicon steel under air cooling condition. The carbon-enriched retained austenite films in the CFB enhanced the toughness of the V-alloyed steel.

scholarly journals Influence of Iron Carbide on Mechanical Properties in High Silicon-added Medium-carbon Martensitic Steels

2020 ◽  
Vol 60 (1) ◽  
pp. 182-189 ◽  
Author(s):  
Shinya Teramoto ◽  
Masahito Imura ◽  
Yuki Masuda ◽  
Toshinori Ishida ◽  
Masato Ohnuma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Iron Carbide ◽  
Martensitic Steels ◽  
Medium Carbon ◽  
High Silicon
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