HIGH RIGIDITY VALVE SHEET RING MADE OF SINTERED ALLOY IN DOUBLE LAYER

摘要

PURPOSE:To obtain a valve sheet ring with higher strength and rigidity by raising the strength and rigidity of a single basic layer and subjecting said basic layer material to a hole countermeasure in the valve sheet ring used for an internal combustion engine. CONSTITUTION:The sliding layer 1a of a valve sheet ring 1 comprises an iron series sintered material into which hard alloy particles have been dispersed, and around said hard alloy particles a matrix into which alloy elements have been dispersed from said particles is yielded. The hard alloy particle has hardness of HV500 or more and compounding ratio 5-30% in the weight ratio. A basic layer material 1b contains 0.5-1.5% carbon and 0.6-3.0% chromium in the weight ratio and further at least either 0.1-0.6% phosphorus or 0.02-0.2% boron. The skeleton density of the whole double layer structure sintered substance after sintering said double layer in a pressure molding process is 6.7- 7.1g/cm<2>, and the pressure loading is adjusted such that the hole rate of the sintered substance may be set to less than 15%. It is required that the sintered substance is 7.6g/cm<3> or more in the density after infiltration and 5% or less in the hole rate of the sintered substance after infiltration.