 Image Number 3 for United States Patent #5853504.
A lapping surface plate consisting of an Fe-base material containing 0.8 to 3.5 wt % of C, 1 to 7 wt % of Si, 5 to 15 wt % of Ni, and 1 wt % or less of Mn, the balance substantially being Fe, further containing 0.1 wt % or less of at least one element selected from the group consisting of Mg, Ca, and Ce, and having a graphite structure and a hardness of 250 Hv or more.
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