Patent ID: 8283046

Claim:
A ferrous sintered multilayer roll-formed bushing having a ferrous sintered sliding material layer which is sinter-bonded to a back metal steel, wherein said ferrous sintered sliding material layer is produced in such a manner that a Fe—C—Cu—Sn based sintered sliding material mixed powder containing at least carbon of 0.40 to 5 wt %, Cu of 13 to 40 wt % and Sn of 0.5 to 10 wt % is preliminarily sinter-bonded to said back metal steel and then finally sinter-bonded by a liquid-phase sintering at high temperatures higher than 1000° C. after bending into a roll, said ferrous sintered sliding material layer has a liquid phase sintering structure having a solid phase state Fe—C based alloy phase containing carbon of 0.45 wt % or more and a liquid phase state Cu—Sn alloy phase dispersed therein, and said solid phase state Fe—C based alloy phase contains one or more specific carbides of Cr 7 C 3 , M 6 C, M 2 C and MC type specific carbides dispersed therein.