Retained austenite in low carbon, manganese steel after intercritical heat treatment

The mechanical properties of Low Carbon Si-Mn Q&P steel are strongly affected by the conditions of heat treatment. Microstructures and mechanical properties of Low Carbon Si-Mn Q&P steel at different partitioning temperature and holding time was investigated. The microstructure was analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is shown that the microstructure of Q&P steel is carbon-depleted lath martensite and carbon enriched retained austenite. The retained austenite appear film-type between the laths. Higher partitioning temperature and longer partitioning time can obtain more retained austenite. It is shown that with increasing partitioning time ultimate tensile strength decreases, while elongation increases obviously. Carbon-enriched metastable retained austenite is considered beneficial because the TRIP phenomenon during deformation can contribute to formability and energy absorption.

Download Full-text

Retained Austenite Control and Extra-Cryogenic Impact Toughness of Fe-3.0%Mn Low Carbon Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.993.520 ◽

2020 ◽

Vol 993 ◽

pp. 520-525

Author(s):

Xiang Tao Deng ◽

Xiao Lin Li ◽

Long Huang ◽

Zhao Dong Wang

Keyword(s):

Heat Treatment ◽

Carbon Steel ◽

Low Temperature ◽

Impact Toughness ◽

Retained Austenite ◽

Uniform Elongation ◽

Low Carbon Steel ◽

Low Carbon ◽

Low Temperature Impact Toughness ◽

The Impact

The control of the retained austenite in Fe-3.0%Mn Low carbon steel by a three-step intercritical heat treatment and the low-temperature impact toughness evolution during the process were analyzed in the present study. The results indicated that the microstructure consisted intercritical ferrite, martensite/bainite and retained austenite. The distribution of carbon and manganese could improve the stability of the austenite located at the grain boundaries of prior austenite and lath boundaries of martensite. For the TRIP effect of the austenite, the excellent plasticity and low temperature toughness was obtained. The impact toughness could reach 200 J (impact energy) at －80 °C during the three-step heat treatment, and the uniform elongation could exceed at 16%.

Download Full-text

High strength-toughness combination of a low-carbon medium-manganese steel plate with laminated microstructure and retained austenite

Materials Science and Engineering A ◽

10.1016/j.msea.2017.09.059 ◽

2017 ◽

Vol 707 ◽

pp. 270-279 ◽

Cited By ~ 8

Author(s):

Y. Zou ◽

Y.B. Xu ◽

Z.P. Hu ◽

S.Q. Chen ◽

D.T. Han ◽

...

Keyword(s):

Retained Austenite ◽

Steel Plate ◽

High Strength ◽

Manganese Steel ◽

Low Carbon ◽

Medium Manganese Steel

Download Full-text

Effect of Heat Treatment Processing Parameters on the Microstructure and Properties of Low-Carbon Cr-Ni-Mo Carburizing Bearing Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.817.231 ◽

2015 ◽

Vol 817 ◽

pp. 231-237 ◽

Cited By ~ 1

Author(s):

Nan Zhang ◽

Mao Sheng Yang ◽

Shi Qing Sun

Keyword(s):

Heat Treatment ◽

Impact Toughness ◽

Retained Austenite ◽

Cryogenic Treatment ◽

Processing Parameters ◽

Bearing Steel ◽

Low Carbon ◽

Quenching Temperature ◽

Tempering Temperature ◽

The Impact

The low-carbon Cr-Ni-Mo carburizing bearing steel was tested with different heat treatment processes. Quenching-tempering temperature and cryogenic treatment (-73°C) wasstudied respectively onthe mechanical properties and microstructure.Results show thatthe increase of quenching temperature causes the micron-sized Cr-rich carbide re-dissolution and smaller quantity of retained austenite, makingthe strength and hardness of the tested steel increase and the impact toughness decrease. The tempering temperaturerising causesthe reduction of micro-residual stresses and smallerdegree of lattice distortion andlower dislocation density, resulting in the decrease of strength and the increase of impact toughness. Cryogenic treatment contributes to the refinement of martensite lath and precipitation of nanosized carbide and lowest quantity of retained austenite, improving the strength and impact toughness of the steel.The good comprehensive mechanical propertieswith the hardness of HRC41.3, tensile strength of 1413MPa,yield strength of 1168MPa, and impact toughness of 162J/cm2 can be obtainedby optimizing the heat treatment process parameters.

Download Full-text