| 摘要 |
The application describes a steel composition consisting essentially ofCarbon 0.50-0.70 weight %Silicon up to 0.40 weight %Manganese 0.55-1.00 weight %Phosphorus 0.030-0.070 weight %Sulphur 0.055 to 0.110 weight %Chromium up to 0.50 weight %Molybdenum up to 0.10 weight %Nickel up to 0.5 weight %Copper up to 0.50 weight %Aluminium up to 0.050 weight %Optionally, Vanadium sufficient to maintain yield strengthNitrogen up to 0.030 weight %, together with, optionally, lead up to 0.4 weight %, and unavoidable impurities, the balance being iron. This steel composition exhibits mechanical properties which are suitable for use in connecting rods but which provide both good fracture splitting performance and good machinability when compared to C70S6 alloys. The application also refers to a fracture splittable steel including between 0.50 to 0.70 wt % C, 0.55 to 1.00 wt % Mn, 0.030 to 0.070 wt % P and 0.055 to 0.110 wt % S, and with an elongation of 25% or less, a reduction of area below 25%, and a V20 machinability (m/min) satisfying the equation:where H is the HV30 hardness of the steel.
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