IRON-BASED SINTERED ALLOT VALVE SEAT FOR INTERNAL COMBUSTION ENGINE HAVING EXCELLENT WEAR RESISTANCE AND ASSEMBLAGE OF VALVE SEAT AND VALVE

PROBLEM TO BE SOLVED: To provide an assemblage between an iron-based sintered alloy valve seat for internal combustion engine having excellent wear resistance and a valve seat having excellent wear resistance and a valve.SOLUTION: An iron-based sintered alloy valve seat having a structure is formed, in the structure a matrix phase is formed into a fine carbide deposition phase in which fine carbide of 10 μm or smaller is deposited and that has hardness of 550 HV or larger by Vickers hardness, and in the matrix phase, hard particles having the hardness of 650 to 1200 HV based on the Vickers hardness are dispersed in the area rate of 20 to 40%, further, a diffusion phase is formed in the area rate of exceeding 0% and 5% or smaller, and particles of a solid lubricant are dispersed in the area rate of 0 to 5%. Thus, even when a valve having a high face surface hardness of 400HV or larger, furthermore, 600HV or larger is used, wear of the opposite valve seat is slight, an assemblage of a valve having excellent wear resistance and a valve seat can be realized, and the endurance of a valve mechanism is drastically improved.SELECTED DRAWING: None 【課題】耐摩耗性に優れた内燃機関用鉄基焼結合金製バルブシートおよび耐摩耗性に優れたバルブシートとバルブとの組合せ体を提供する。【解決手段】基地相を、10μm以下の微細炭化物が析出し、ビッカース硬さで550HV以上の硬さを有する微細炭化物析出相とし、基地相中に、ビッカース硬さで650〜1200HVの硬さを有する硬質粒子を、面積率で20〜40％分散させ、さらに拡散相を面積率で0％超え5％以下形成し、固体潤滑剤粒子を面積率で0〜5％分散させた組織を有する鉄基焼結合金製バルブシートとする。これにより、400HV以上、さらには600HV以上の高フェース面硬さのバルブが使用されても、相対するバルブシートの摩耗は少なく、耐摩耗性に優れたバルブとバルブシートの組合せ体を実現でき、弁機構の耐久性が格段に向上する。【選択図】なし