Precipitation and control of BN inclusions in 42CrMo steel and their effect on machinability

Abstract

The precipitation and control of boron nitrogen (BN) inclusions in 42CrMo steel were investigated and their effect on machinability was analyzed. First, the precipitation regularity of BN in 42CrMo steel was studied by theoretical calculation. Then, the machinability of the steel was investigated through contrast cutting experiments, and the composition and cooling rate of the steel were controlled to analyze the variation laws of the size, distribution, and area ratio of BN inclusions. Finally, the results were combined with the machinability of the steel to analyze the relationship among them. It is found that the machinability of the steel is mainly influenced by the diameter and quantity of BN inclusions. Fine and dispersedly distributed BN inclusions are more beneficial for the improvement in machinability of 42CrMo steel than coarse and sparse BN inclusions.

Keywords

steel / inclusions / boron nitrogen / precipitation / machinability

References

[1] Zhang YJ, Zhu C, Wang LF, Zhao HC, Chen MY, Wang QL, Jin YC, Han JT. Development of free cutting steel for machine structure without lead. Mater. Rev., 2005, 19(12): 68.

[2] Chen M, Liu G, Zhang XH, Shen Z, Yang GJ. Experiment on machinability of new developed low carbon sulphur free-cutting steel. Chin. J. Mech. Eng., 2007, 43(9): 161.

[3] Feng SH. Development of free cutting steel at home and abroad in 1980s. Manuf. Tech. Mach. Tool, 1994, 44(7): 51.

[4] Li LS, Zhu R, Guo HJ, Dong J, Li FG. Development of non-leaded free-cutting steel by adding tin. J. Univ. Sci. Technol. Beijing, 2003, 25(4): 312.

[5] Pu YM. Research on development free-cutting steel wire rod. Steel Wire Prod., 2004, 30(2): 19.

[6] Nakamura S, Wen F. Development trends of cutting metal materials. Foreign Low Alloy Steel Alloy Steel, 1990, 2(1): 26.

[7] Quan R. Development of cutting steel in Japan. World Metals, 2011

[8] Xiao YL, Tang MZ. Development of BN free cutting steel without Lead. World Metals, 2009

[9] Zhang WM. New free cutting steel. J. Int. Met. Work, 2000, 12(4): 35.

[10] Tanaka R, Yamane Y, Sekiya K, Narutaki N, Shiraga T. Machinability of BN free-machining steel in turning. Int. J. Mach. Tools Manuf., 2007, 47(12–13): 1971.

[11] Tanaka R, Lin Y, Hosokawa A, Ueda T, Yamada K. Influence of additional electrical current on machinability of BN free-machining steel in turning. J. Adv. Mech. Des. Syst. Manuf., 2009, 3(2): 171.

[12] Yamane Y, Tanaka R, Narutaki N. Machinability of BN added steels. J. Jpn. Soc. Precis. Eng., 1998, 64(9): 1370.

[13] Tanaka R, Yamane Y, Ueda T, Hosokawa A, Shiraga T. Drilling of BN added free-machining steel. J. Jpn. Soc. Abras. Technol., 2008, 52(1): 28.

[14] Tanaka R, Yamane Y, Okada M, Hosoka A, Ueda T. End milling of free-machining steel for high speed machining: tool wear and cutting temperature in cutting BN added steels. J. Jpn. Soc. Precis. Eng., 2007, 73(7): 803.

[15] Yamashita H, Maeda K, Nishikawa T, Tanabe E. The machining characteristics of BN free machining steel and application to molding die. Bull. West. Hiroshima Prefect. Ind. Res. Inst., 2005, 14, 52.

[16] Chen JX. Common Charts and Databook for Steelmaking, 1984, Beijing, Metallurgical Industry Press, 454.

[17] Li PS, Xiao LJ, Xie Z. Thermodynamic analysis of AlN and BN competitive precipitation in low carbon steel. J. Iron Steel Res., 2009, 21(5): 16.

[18] Yong QL. Secondary Phases in Steels, 2006, Beijing, Metallurgical Industry Press, 167.

[19] Wang WD, Zhang SH, He XL. Diffusion of boron in alloys. Acta Metall. Mater., 1995, 43(4): 1693.

[20] Shen H. Mechanical Engineering Handbook, 1978, Beijing, China Machine Press, 935.

[21] Manohar PA, Dunne DP, Chandra T, Killmore CR. Grain growth predictions in microalloyed steels. ISIJ Int., 1996, 36(2): 194.

[22] Ramírez-López A, Aguilar-López R, Kunold-Bello A, González-Trejo J, Palomar-Pardavé M. Simulation factors of steel continuous casting. Int. J. Miner. Metall. Mater., 2010, 17(3): 267.

[23] Ramírez-López A, Aguilar-López R, Palomar-Pardavé M, Romero-Romo MA, Muñoz-Negrón D. Simulation of heat transfer in steel billets during continuous casting. Int. J. Miner. Metall. Mater., 2010, 17(4): 403.

[24] Yin SK, Komatsu H, Tanino M. The precipitation of BN in isothermal treatment process. Acta Metall. Sin., 1982, 18(5): 565.

[25] Xiao LJ, Guo YD, Liu JQ, Qiu ST, Li XY. The effect of boron on precipitation of AlN and MnS in lowcarbon Al-killed steel. J. Mater. Metall., 2006, 5(1): 53.