Correlating Test-Data on Heat-Treated Chromium-Vanadium Steels 280023
AN outline is given of the work performed and the method of procedure followed in correlating test results on specimens of heat-treated S.A.E. chromium-vanadium steel 6130 as a basis for revision of the physical-property charts for certain automotive steels. Revision of the charts was proposed by the Iron and Steel Division of the Standards Committee of the Society, and a subcommittee, of which the author is a member, was appointed to carry on the preliminary work of revision. The paper is a report of the results of the tests made.
Test specimens of S.A.E. Steel 6130, to be drawn at three different temperatures after quenching, were prepared by four steel manufacturers. These were distributed among 30 cooperating laboratories, which made a series of about 115 tests including complete chemical analysis, tensile-strength, and Brinell, scleroscope and Rockwell hardness tests on the specimens.
Results of the tests are given in frequency or probability curves, rather than in straight-line curves of averages alone, since the latter are regarded as an unsatisfactory method of expressing the results of such an investigation because of the variables. It was necessary to express the results so as to indicate a range, limited by minimum and maximum values, within which users of the charts might be expected to obtain satisfactory results.
The frequency curves show that the test specimens had a 12-point carbon-range, which approaches closely the S.A.E. specification. They also show a range in tensile-strength of about 34,000, 27,000 and 24,000 lb. per sq. in. for draws at 800, 1000 and 1200 deg. fahr., respectively.