| 摘要 |
A process controls, in a foundry mould against at least one metal cooler, the hardening of a lamellar cast iron component in which additive elements are added to the molten iron before casting in order to promote the concomitant formation of carbides and graphite. The additives used to promote hardening are made up of bismuth and/or tellurium and/or boron whilst the additives used to promote the formation of graphite are made up of graphite based innoculants and/or silicon based innoculants. The graphite based innoculants and/or the silicon based innoculants may also include one or more of the following elements: strontium, zirconium, barium, calcium, aluminium or rare earth metals. The cast iron used in the process has the following compsn: 2.6 to 3.6% carbon; 1.2 to 2.6% silicon; 0.3 to 1.0% manganese; and 0.003 to 0.15% sulphur. USE/ADVANTAGE - Used to control the hardening of lamellar cast iron components such as camshafts, rolling mill rolls and other similar components. Allows greater control of the factors that affect the formation of graphite in a cast iron and consequently reduces to a max and stabilises the transition zone situated between a surface hardened zone in which the carbon is precipitated in the form of carbides and a softer central zone in which the carbon is precipitated in the form of graphite. The transition zone incorporates both carbides and graphite.
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