High machinability iron base sintered alloy for valve seat inserts
AssigneeFederal-Mogul World Wide, Inc.
InventorsMark Birler, Salvator Nigarura, Juan Trasorras
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Abstract
A ferrous sintered valve seat material is made of mixed powders comprising a sinter-hardenable phase and a finely dispersed carbide phase. The powder mixture comprises a sinter-hardening prealloyed powder forming 75 to 90 wt. % of the mixture and a tool steel powder with finely dispersed carbides forming 5 to 25% of the mixture. Machinability additives of MnS, CaF2 or MoS2 types are added in an amount of 1 to 5 wt. %. Improved thermal conductivity is obtained by infiltrating the compact with Cu up to 25 wt. %.
Claims31
A sinter-hardenable powder metal valve seat material for internal combustion engines comprising a mixture of:
- a sinter-hardenable ferrous powder forming 75-90 wt. % of the mixture;
- a tool steel powder;
- a solid lubricant;
- Cu added by infiltration during sintering, and
- wherein the ferrous powder is prealloyed with 2 to 5 wt. % Cr.
A sintered valve seat insert material for internal combustion engines with improved machinability, wear resistance and high thermal conductivity, where said material consists of a mixture of a Cr-containing sinter-hardening ferrous alloy powder, a tool steel powder, a solid lubricant and Cu added by infiltration of compacts during sintering.
A sintered valve seat insert for internal combustion engines exhibiting good machinability, wear resistance and high thermal conductivity, comprising:
- a matrix of a sinter-hardening prealloyed or admixed Fe powder containing 2 to 5 wt. % Cr mixed and sintered with an amount of tool steel powder, a solid lubricant and an amount of Cu added by infiltration during sintering.
A method of making a sintered powder metal valve seat insert for internal combustion engines exhibiting good machinability, wear resistance and high thermal conductivity, comprising:
- mixing Cr-containing sinter-hardenable ferrous powder with tool steel powder and a solid lubricant;
- compacting and sintering the mixture;
- and
- during sintering, infiltrating the compact with Cu.
Dependencies are inferred from the claim text.