Method for manufacturing a slide member

Claim 1

A method of manufacturing a slide member, said method comprising the steps of: (a) mixing an alloy powder comprising by weight from 2.5% to 7.5% Cr, from 0.1% to 3.0% Mn, from 0.2% to 0.8% P, from 1.0% to 5.0% Cu, from 0.5% to 2.0% Si, from 0.0% to 3% Mo, from 1.5% to 3.5% C, and the balance Fe having less than 2% impurities; then (b) compressing said alloy powder at a molding product pressure of 5 to 7 tons/cm 2 to form a compressed powder mass; then (c) sintering said compressed powder mass at a temperature of between 1020° C. and 1180° C. to produce a sintered alloy mass having a surface thereon and a plurality of internal pores therein; then (d) subjecting said sintered alloy mass to a pressure of between 0.1 atmospheres and 0.8 atmospheres for from 1.5 to 2.5 hours, thereby facilitating the entry of a soaking gas into said pluraity of internal pores in the next step; and then (e) exposing said sintered alloy mass to a soaking gas containing 20% to 40% by volume of steam and 60% to 80% by volume of a gas selected from the group consisting of non-oxidizing gas, an endothermic gas, or a mixture thereof for between 0.5 hours and 5 hours at a temperature of between 450° C. and 550° C. and at a pressure of between 0.1 and 0.8 atmospheres, thereby forming a film of tri-iron tetroxide on the surface of said sintered alloy mass and on the walls of said plurality of internal pores in said sintered alloy mass.

Claim 2

A method of manufacturing a slide member, said method comprising the steps of: (a) mixing an alloy powder comprising by weight from 2.5% to 7.5% Cr, from 0.1% to 3.0% Mn, from 0.2% to 0.8% P, from 1.0% to 5.0% Cu, from 0.5% to 2.0% Si, from 0.0% to 3% Mo, from 1.5% to 3.5% C, and the balance Fe having less than 2% impurities; then (b) compressing said alloy powder at a molding product pressure of 5 to 7 tons/cm 2 to form a compressed powder mass; then (c) sintering said compressed powder mass at a temperature of between 1020° C. and 1180° C. to produce a sintered alloy mass having a surface thereon and a plurality of internal pores therein; then (d) subjecting said sintered alloy mass to a pressure of between 0.1 atmospheres and 0.8 atmospheres for from 1.5 to 2.5 hours, thereby facilitating the entry of a soaking gas into said pluraity of internal pores in the next step; and then (e) exposing said sintered alloy mass to a soaking gas containing 20% to 40% by volume of steam and 60% to 80% by volume of a gas selected from the group consisting of non-oxidizing gas, an endothermic gas, or a mixture thereof for between 0.5 hours and 5 hours at a temperature of between 450° C. and 550° C. and at a pressure of between 0.1 and 0.8 atmospheres, thereby forming a film of tri-iron tetroxide on the surface of said sintered alloy mass and on the walls of said plurality of internal pores in said sintered alloy mass.