Advertisement

Use of the Scanning Electron Microscope to Study the Function of Manganese Sulphide Inclusions in Resulphurised Free-Machining Steels

  • W. J. Wilber
  • A. W. J. Chisholm
  • E. J. Pattinson
Chapter

Summary

The scanning electron microscope provides the means for a new approach to the study of the mechanism by which manganese sulphide inclusions affect the machinability of free-machining steels. The use of this instrument in the experimental work described here has led to the conclusion that manganese sulphide inclusions affect the machinability of resulphurised steels chiefly by promoting the formation of a stable built-up cap on the cutting edge of the tool, which protects the cutting edge and reduces the rate of tool flank wear. A mechanism, embodying phenomena which are construed to be peculiar to the machining of resulphurised steel, is proposed here to explain how manganese sulphide inclusions promote this built-up cap formation. This function of manganese sulphide in re-sulphurised steel differs from that advanced previously, which relies on the formation of lubricating films on the tool surfaces.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    MOORE, C., ‘The steelmakers approach to machinability,’ MTDR Conf. No. 9, M.S. 43 (1968).Google Scholar
  2. 2.
    MERCHANT, M. E., and ZLATIN, N., ‘Basic reasons for good machinability of free machining steels,’ Trans. A.S.M. 41, (1949), pp. 647–677.Google Scholar
  3. 3.
    BOULGER, F. W., LANKFORD, W. T., HARTNER, H. E., and GARVEY, T. M., ‘Force relationships in machining low carbon steels.’ Trans. A.S.M.E., 79, No. 5 (1957), pp. 1155–1164.Google Scholar
  4. 4.
    SHAW, M. C., USUI, E., and SMITH, P. A., ‘Free machining steel: III. Cutting forces; Surface finish and chip formation,’ Trans. A.S.M.E., B, 83 (1961), pp. 181–193.Google Scholar
  5. 5.
    USUI, E., and SHAW, M. C., ‘Free machining steel: IV. Tools with reduced contact length,’ Trans. A.S.M.E., B, 84 (1962), pp. 89–102.Google Scholar
  6. 6.
    TRENT, E. M., ‘Metallurgical changes at the tool/work interface,’ I.S.I. Special Report No. 94 (1965), pp. 77–88.Google Scholar
  7. 7.
    RICHARDSON, B. D., and CHISHOLM, A. W. J., ‘A study of the effect of non-metallic inclusions on the machinability of two ferrous materials,’ Proc. Inst. Mech. Engrs. Paper 18, (1965), pp. 129–142.Google Scholar
  8. 8.
    OATLEY, C. W., NIXON, W. C., and PEASE, R. F. W., ‘Advances in electronics and electron physics,’ 21 (Academic Press, New York, 1965).Google Scholar
  9. 9.
    THORNTON, P. R., ‘Scanning electron microscopy,’ (Chapman and Hall, 1968).Google Scholar
  10. 10.
    TRENT, E. M., ‘Tool wear and machinability,’ J., Inst. Prod. Engrs., 38, No. 3 (1959), pp. 105–130.CrossRefGoogle Scholar
  11. 11.
    MARSTON, G. J., and MURRAY, J. D., ‘Summary report on the machinability of low carbon free-cutting steels,’ B.S.C. Internal Report, Ref. No. AM.5267/24/68/A (1968).Google Scholar
  12. 12.
    CHISHOLM, A. W. J., and McDOUGALL, D., ‘Progress report on an experimental investigation into the effect of strain hardening on the mechanics of orthogonal cutting,’ D.S.I.R., M.E.R.L. Plasticity Report No. 61 (1952).Google Scholar
  13. 13.
    WILBER, W. J., ‘The effect of manganese sulphide inclusions on the mechanism of cutting and tool wear in the machining of low carbon steels,’ PhD Thesis, University of Salford (1970).Google Scholar

Copyright information

© Macmillan Publishers Limited 1972

Authors and Affiliations

  • W. J. Wilber
    • 1
  • A. W. J. Chisholm
    • 2
  • E. J. Pattinson
    • 2
  1. 1.City of Birmingham PolytechnicPerry BarrUK
  2. 2.Department of Mechanical EngineeringSalfordUniversity of SalfordUK

Personalised recommendations