Study of Thermal Stability of Phosphorus Bainitic Gray Cast Iron for Valve Seats of Internal Combustion Engines

A study was performed of the effect of the operating temperature (~550°C) simulation in a new design of the cylinder head for internal combustion engines (ICE) of cars on the thermal stability of the structure and the hardness of castings of exhaust valve seat inserts made of phosphorus bainitic gray iron (in the cast state and tempered) of specially selected chemical composition for the production of bainite metal base under continuous cooling without austempering. The effects of the single and double tempering on changes in the cast iron structure and hardness are shown. The performance of the bainitic structure for valve seats was found to be unsatisfactory since it fails to maintain the required hardness level.