Enhanced Mechanical Properties of a 0.22C-Mn-Si-Cr Low Alloyed Steel Treated by ART and Q&P Processes

Abstract:

There is a currently desirable demand for high strength steels with good ductility reduce the weight of steel parts for automobile and train applications. Retained austenite in steels can improve the toughness and plasticity. The austenite reverse transformation + quenching and partitioning (ART + Q&P) process was treated on a 0.2C-Mn-Si-Cr low alloyed steel, a multiphase microstructure composed of intercritical ferrite (IF), martensite, bainite and retained austenite (RA) can be obtained in the low carbon steel. Microstructures of the steel treated by different heat treatments were characterized by SEM and XRD. Results show that the formation of RA in low alloy steel depends on the following: (1) the enrichment of the carbon and manganese in the reversed austenite during the ART step; (2) the secondary enrichment of carbon in retained austenite during the following Q&P step. High fraction of RA (14 vol.%) was obtained through the two-step element enrichment treatment (ART + Q&P). Due to continuous TRIP effect of RA during the deformation, a good combination of strength and plasticity was achieved in our works: the product of strength and elongation is greater than 35 GPa•%, the tensile strength is more than 1230 MPa, the yield strength greater than 890 MPa, the total elongation is about 28.6%.

• Periodical: Advanced Materials Research (Volumes 1004-1005)
• Pages: 203-208
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1004-1005.203
• Online since: August 2014
• Authors: Bai Feng An, Gu Hui Gao*, Xiao Lu Gui, Zhun Li Tan, Bing Zhe Bai
• Keywords: Austenite Reverse Transformation, Bainite, Mechanical Property, Q&P, Retained Austenite

References

[1] Speer J G, Matlock D K, De Cooman B C, Schroth J G. Acta Mater, 2003; 51: 2611.

[2] Matlock D K, Brautigam V E, Speer J G. Mater Sci Forum, 2003; 426-432: 1089.

[3] Ren Yongqiang, Xie Zhenjia, Shang Chengjia J. Acta Metallurgica Sinica, 2012; 48 (9): 1074-1080. (In Chinese).

[4] Sugimoto K, Tsunezawa M, Hojo T, Ikeda S. ISIJ Int, 2004; 44: 1608.

[5] Matsumura O, Sakuma Y, Takechi H. ISIJ Int, 1992; 32: 1014.

[6] Shi J, Sun X J, Wang M Q, Hui W J, Dong H, Cao W Q. Scr Mater, 2010; 63: 815.

[7] Wang C Y, Shi J, Cao W (a, Dong H. Mater Sci Eng, 2010; A527: 3442.

[8] Li H Y, Lu X W, Wu X C, Min Y A, Jin X J. Mater Sci Eng, 2010; A527: 6255.

[9] Santofimia M J, Zhao L, Sietsma J. Metall Mater Trans, 2009; A40: 46.

[10] Mukherjee M, Mohanty O N, Hashimoto S, Hojo T, Sugimoto K. ISIJ Int, 2006; 46: 316.

[11] Sugimoto K, Usui N, Kobayashi M, Hashimoto S. ISIJ Int, 1992; 32: 1311.

[12] Raabe D, Ponge D, Dmitrieva O, Sander B. Scr Mater, 2009; 60: 1141.

[13] Santofimia M J, Nguyen-Minh T, Zhao L, Petrov R, Sabirov I, Sietsma J. Mater Sci Eng, 2010; A527: 6429.

[14] Santofimia M J, Zhao L, Sietsma J. Metall Mater Traps, 2011; 42A: 3620.