| 摘要 |
PCT No. PCT/GB92/01665 Sec. 371 Date Mar. 15, 1994 Sec. 102(e) Date Mar. 15, 1994 PCT Filed Sep. 11, 1992 PCT Pub. No. WO93/05908 PCT Pub. Date Apr. 1, 1993A method of producing a chilled iron camshaft from a chromium containing cast iron is described. The cast iron material contains between 0.5 wt % to 1.2 wt % of chromium. The camshaft having a white iron structure adjacent chill inserts in a casting mold and a grey iron structure in substantially all other regions remote from the chills. The method comprising the steps of assembling a sand casting mold having a camshaft shaped cavity and also having chill inserts adjacent the cavity regions where white iron is desired. Preparing a molten metal charge of cast iron having a carbon equivalent lying in the range from 3.5 up to 4.0 wt % and adding sufficient nucleant prior to pouring to fill the mold cavity, to ensure that under cooling of residual liquid remaining after solidification of the white iron structure adjacent the chills remains above the iron-cementite eutectic temperature prior to solidification into grey iron.
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