Enhanced Strength and Toughness of Low‐Carbon Bainitic Steel by Refining Prior Austenite Grains and Austempering Below M s

2021 ◽  
pp. 2100263
Author(s):  
Chunxia Yao ◽  
Huifang Lan ◽  
Zhen Tao ◽  
Raja Devesh Kumar Misra ◽  
Linxiu Du
Keyword(s):  
Prior Austenite ◽  
Bainitic Steel ◽  
Low Carbon ◽  
Austenite Grains ◽  
Strength And Toughness

scholarly journals Exploring the Difference in Bainite Transformation with Varying the Prior Austenite Grain Size in Low Carbon Steel

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 988 ◽  
Author(s):  
Liangyun Lan ◽  
Zhiyuan Chang ◽  
Penghui Fan
Keyword(s):  
Grain Size ◽  
Prior Austenite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Bainite Transformation ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Austenite Grains ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

The simulation welding thermal cycle technique was employed to generate different sizes of prior austenite grains. Dilatometry tests, in situ laser scanning confocal microscopy, and transmission electron microscopy were used to investigate the role of prior austenite grain size on bainite transformation in low carbon steel. The bainite start transformation (Bs) temperature was reduced by fine austenite grains (lowered by about 30 °C under the experimental conditions). Through careful microstructural observation, it can be found that, besides the Hall–Petch strengthening effect, the carbon segregation at the fine austenite grain boundaries is probably another factor that decreases the Bs temperature as a result of the increase in interfacial energy of nucleation. At the early stage of the transformation, the bainite laths nucleate near to the grain boundaries and grow in a “side-by-side” mode in fine austenite grains, whereas in coarse austenite grains, the sympathetic nucleation at the broad side of the pre-existing laths causes the distribution of bainitic ferrite packets to be interlocked.

Influence of Austenite Grain Size on the Crystallography of Allotriomorphic Ferrite in a Low Carbon Steel

2012 ◽  
Vol 535-537 ◽  
pp. 605-610 ◽  
Author(s):  
Yin Bai ◽  
Hui Guo ◽  
Shan Wu Yang ◽  
Xin Lai He
Keyword(s):  
Grain Size ◽  
Prior Austenite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Allotriomorphic Ferrite ◽  
Austenite Grains ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

The influence of prior austenite grain size on the crystallography of allotriomorphic ferrite is investigated in a low carbon steel. The results show that as the prior austenite grain size decreasing, the fraction of allotriomorphic ferrites that do not keep K-S orientation relationship with any surrounding prior austenite grains is increased. It is observed that such ferrites usually form at the grain edges or grain corners. It is known that with the grain size decreasing, the fraction of grain edges and corners increases. It is suggested that the free energy of the defects at such nucleation sites is higher than that at grain faces, and the nucleation barrier of ferrite is lower. As a result, the possibility for the ferrite to form that does not have orientation relationship with all surrounding austenite grains is increased at such sites.

UNS G81150

Alloy Digest ◽  
1990 ◽  
Vol 39 (11) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Alloy Steel ◽  
Heat Treating ◽  
Low Carbon ◽  
Wear Resistant ◽  
Nickel Chromium ◽  
Steel Mills ◽  
Medium Strength ◽  
Strength And Toughness

Abstract UNS G 81150 is a low-carbon nickel-chromium-molybdenum carburizing steel recommended for applications where a core of medium strength and toughness combined with a wear-resistant carburized case is sufficient. It has medium hardenability and can be used without carburizing. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-453. Producer or source: Alloy steel mills and foundries.

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