| 摘要 |
A most preferred composition for the mixture, prior to sintering into an article (ideally a valve seat insert), is as follows: 35% hard phase, 65% matrix (excepting incidental impurities), the hard phase component being 2.2% C, 29.1% Cr, 4.9% Co, 5.3% Ni, 20.2% W with the balance being Fe and allowing less than 2% for one or more machinability aids and solid lubricants, and the matrix component being one of a high chrome steel powder (e.g. 18% Cr, 1% Ni, 2.5% Mo, balance Fe), a low alloy steel powder (3% Cu, 1% C, balance Fe; 3% Cr, 0.5% Mo, 1% C, balance Fe; 4% Ni, 1.5% Cu, 0.5% Mo, 1% C, balance Fe; 4% Ni, 2% Cu, 1.4% Mo, 1% C, balance Fe), or a tool steel powder (5% Mo, 6% W, 4% Cr, 2% V, 1% C, balance Fe), or a low-alloy steel powder as above but which issued in conjunction with a copper infiltration process during sintering. |
