Powder metal valve guide

摘要

A powder metal blend for making a powder metal part especially a valve guide 14 for an internal combustion engine particularly suited for operation where there is little or no engine oil lubricant at the valve stem 30 and valve guide 14 interface. The powder metal blend having a chemical composition on a weight percent basis of about 2 to about 10 percent copper; about 0.5 to about 5.0 percent solid lubricant; about 1.0 to about 3.0 percent graphite; about 1.0 to about 8.0 percent bronze; about 0.2 to about 1.5 percent copper-and/or iron phosphorus; about 0.3 to about 1.0 percent fugitive lubricant; and the balance being a low alloy steel powder containing about 0.3 to about 1.0 percent manganese.