Ferrous sintered multilayer roll-formed bushing, producing method of the same and connecting device

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 contains at least carbon of 0.4 to 15 wt %, Cu of 13 to 40 wt % and Sn of 0.5 to 10 wt % and is produced in such a manner that a Fe—C—Cu—Sn based sintered sliding material mixed powder 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,
• a ferrous alloy powder to be contained in said Fe—C—Cu—Sn based sintered sliding material mixed powder contains Cu of a solid solubility limit or more and at least 2 wt % or more to 40 wt % or less and carbon of 0.2 wt % or more,
• 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 0.2 wt % or more and a liquid phase state Cu—Sn alloy phase dispersed therein, and
• said ferrous sintered sliding material layer contains one or more powder particles of metal powder of Cr, Co, Mo and W which have significantly small solid solubility with Cu;
• alloy powder of NiMo, CoMo and FeMo which contain Mo intermetallic compound;
• solid lubricant powder of graphite, BN and CaF2;
• and powders of specific carbide, nitride and oxide mainly consisting of an alloy element of Cr, Mo, W, V, Ti and Zr dispersed therein.

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 contains at least carbon of 0.4 to 15 wt %, Cu of 13 to 40 wt % and Sn of 0.5 to 10 wt % and is produced in such a manner that a Fe—C—Cu—Sn based sintered sliding material mixed powder is preliminarily sinter-bonded to said back metal steel and then finally sinter-bonded by a liquid-phase sintering at temperatures of 1000° C. or higher, which is higher than a preliminary sintering temperature, after bending into a roll,
• a ferrous alloy powder to be contained in said Fe—C—Cu—Sn based sintered sliding material mixed powder contains Cu of a solid solubility limit or more and at least 2 wt % or more to 40 wt % or less and carbon of 0.2 wt % or more,
• 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,
• said solid phase state Fe—C based alloy phase contains one or more carbides of Cr7C3, M6C, M2C and MC type carbides dispersed therein, and
• said ferrous sintered sliding material layer contains one or more powder particles of solid lubricant powders of Cr, Co, Mo, W, NiMo, CoMo, FeMo, graphite, BN and CaF2;
• and powders of nitride and oxide mainly consisting of one or more alloy elements of Cr, Mo, W, V, Ti and Zr dispersed therein.

A method of producing a ferrous sintered multilayer roll-formed bushing, the method comprising:

• preliminarily sintering bonding a Fe—C—Cu—Sn based sintered sliding material mixed powder to a back metal steel at a temperature range of 750 to 950° C. to form a preliminary sintered layer on said back metal steel;
• mechanically rolling said preliminary sintered layer;
• bending said preliminary sintered layer and said back metal steel into a roll;
• and
• finally sintering said preliminary sintered layer at temperatures of 1000° C. or higher, which is higher than the preliminary sintering temperature, to form a ferrous sintered sliding material layer on said back metal steel,
• wherein said Fe—C—Cu—Sn based sintered sliding material mixed powder contains at least C of 0.4 to 5 wt %;
• Cu of 13 to 40 wt %;
• and Sn of 0.5 to 10 wt %,
• said ferrous sintered sliding material layer after said final sintering 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 carbides of Cr7C3, M6C, M2C and MC type carbides dispersed therein.

A method of producing of a ferrous sintered multilayer roll-formed bushing, the method comprising:

• preliminarily sintering bonding a Fe—C—Cu—Sn based sintered sliding material mixed powder to a back metal steel at a temperature range of 750 to 950° C. to form a preliminary sintered layer on said back metal steel;
• mechanically rolling said preliminary sintered layer;
• bending said preliminary sintered layer and said back metal steel into a roll;
• and
• finally sintering said preliminary sintered layer at 1000° C. or higher, which is higher than a preliminary sintering temperature, to form a ferrous sintered sliding material layer on said back metal steel,
• wherein said Fe—C—Cu—Sn based sintered sliding material mixed powder contains at least C of 0.2 to 15 wt % or 0.2 to 9 wt %;
• Cu of 13 to 40 wt %;
• and Sn of 0.5 to 10 wt %,
• a ferrous alloy powder to be contained in said Fe—C—Cu—Sn based sintered sliding material mixed powder contains Cu of a solid solubility limit or more and at least 2 wt % or more to 40 wt % or less and carbon of 0.2 wt % or more,
• said ferrous sintered sliding material layer after said final sintering has a liquid phase sintering structure having a solid phase state Fe—C based alloy phase containing carbon of 0.2 wt % or more and a liquid phase state Cu—Sn alloy phase dispersed therein, and
• said ferrous sintered sliding material layer contains one or more powder particles of metal powder of Co, Cr, Mo and W;
• alloy powder of NiMo, CoMo and FeMo which contain Mo intermetallic compound;
• solid lubricant powder of graphite, BN and CaF2;
• and powder of specific carbide, nitride and oxide which mainly consist of one or more alloy elements of Cr, Mo, W, Ti, Zr and Nb dispersed therein.

A method of producing a ferrous sintered multilayer roll-formed bushing, the method comprising:

• preliminarily sintering bonding a Fe—C—Cu—Sn based sintered sliding material mixed powder to a back metal steel at a temperature range of 750 to 950° C. to forms a preliminary sintered layer on said back metal steel;
• mechanically rolling said preliminary sintered layer;
• bending said preliminary sintered layer and said back metal steel into a roll;
• and
• finally sintering said preliminary sintered layer at 1000° C. or higher, which is higher than a preliminary sintering temperature, to form a ferrous sintered sliding material layer on said back metal steel,
• wherein said Fe—C—Cu—Sn based sintered sliding material mixed powder contains at least C of 0.4 to 5 wt %;
• Cu of 13 to 40 wt %;
• and Sn of 0.5 to 10 wt %,
• a ferrous alloy powder to be contained in said Fe—C—Cu—Sn based sintered sliding material mixed powder contains Cu of a solid solubility limit or more and at least 2 wt % or more to 40 wt % or less and carbon of 0.45 wt % or more,
• said ferrous sintered sliding material layer after said final sintering 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 ferrous sintered sliding material layer contains one or more powder particles of metal powder of Co, Cr, Mo and W;
• alloy powder of NiMo, CoMo and FeMo which contain Mo intermetallic compound;
• solid lubricant powder of graphite, BN and CaF2;
• and powder of nitride and oxide which mainly consisting of one or more alloy elements of Cr, Mo, W, Ti, Zr and Nb dispersed therein.