Analysis on composition and inclusions of ballpoint pen tip steel
- 20 Downloads
Ballpoint pen tip steel, a super free-cutting stainless steel, exhibits excellent corrosion resistance and good machining properties. In this study, inductively coupled plasma spectroscopy, metallographic microscopy, and scanning electron microscopy were used to determine the elemental contents in five ballpoint pen tips and their components, morphologies, and inclusion distributions. The results showed that the steels were all S–Pb–Te super free-cutting ferritic stainless steel. The free-cutting phases in the steels were mainly MnS, Pb, and small amounts of PbTe. MnS inclusions were in the form of chain distributions, and the aspect ratio of each size inclusion in the chain was small. The stress concentration effect could substantially reduce the cutting force when the material was machined. Some of the Pb was distributed evenly in the steel matrix as fine particles (1–2 μm), and the rest of the Pb was distributed at the middle or at both ends of the MnS inclusions. The Pb plays a role in lubrication and melting embrittlement, which substantially increases the cutting performance. PbTe was also usually distributed in the middle and at both ends of the MnS inclusions, and Te could convert the sulfides into spindles, thereby improving the cutting performance of the steel.
Keywordsballpoint pen tip free-cutting stainless steel inclusions lead tellurium
Unable to display preview. Download preview PDF.
This work is supported by the National Nature Science Foundation of China (No. 51474142).
- P. Gao, K.M. Chen, Q.X. Dai, A.F. Meng, and T.F. Dai, Microstructure and cutting performance of new free-cutting stainless steels used for ball point pen, Mater. Mech. Eng., 34(2010), No. 9, p. 41.Google Scholar
- L.S. Li, R. Zhu, H.J. Guo, J. Dong, and F. Li, Development of non-leaded free-cutting steel by adding tin, J. Univ. Sci. Technol. Beijing, 25(2003), No. 4, p. 312.Google Scholar
- L.S. Li, R. Zhu, Y.H. Sun, H.J. Guo, H. Yin, and J. Dong, Form and distribution of inclusions and tin in free-cutting steel, J. Univ. Sci. Technol. Beijing, 26(2004), No. 5, p. 471.Google Scholar
- Y.N. Wang, Y.P. Bao, M. Wang, and L.C. Zhang, Smelting process and machinability of BN-type free-cutting steel, J. Univ. Sci. Technol. Beijing, 35(2013), No. 7, p. 869.Google Scholar
- Y.J. Xia, F.M. Wang, C.R. Li, J.L. Wang, and Z.Y. Wu, Study on the formation behavior of sulfides in free-cutting steel by unidirectional solidification, J. Univ. Sci. Technol. Beijing, 34(2012), No. 2, p. 118.Google Scholar
- G.A. Yan, Z. Qin, Z.H. Tian, Y.H. Sun, and K.K. Cai, Inclusion morphology control in medium-carbon calcium sulphur free-cutting steel, J. Univ. Sci. Technol. Beijing, 29(2007), No. 7, p. 685.Google Scholar
- Y.N. Wang, J. Yang, and Y.P. Bao, Nanoindentation characterization of non-metallic inclusions in free cutting steel, J. Univ. Sci. Technol. Beijing, 36(2014), No. 7, p. 903.Google Scholar
- S. Zhang, S.F. Zhang, J.S. Li, and L.Z. Wang, Morphology of MnS inclusions in Y15 high sulfur free-cutting steel by tellurium treatment, Iron Steel, 52(2017), No. 9, p. 27.Google Scholar
- D.Z. Li, S.Q. Gao, L.F. Zhang, Z.Y. Wang, and X.Q. Dong, Formation and behavior of telluride in free cutting steels, Iron Steel, 22(1987), No. 4, p. 38.Google Scholar