What is the material of the engine valve, especially the exhaust valve?
The small end of quenching, the hardness of 50H RCmin, effectively improve the small end impact resistance to pitting corrosion, because the locking groove of three groove structure, in order to cope with the work of spin, quenching slots; and the rod head material friction butt welding and weld strength, more than 81 0MPa; the surface of the rod chrome plating. The chrome layer thickness of 0.0015 0.003mm, the hardness above 600HV, ensure the valve rod wear resistance, improve service life.
The exhaust valve consists of three parts of the materials, the head is 21 4N austenitic materials by solid solution and aging treatment, the grain size of 6 - 9, the hardness more than 30HRC, can work for a long time at 850 degrees Celsius; head cone surface welding of cobalt base alloy STELLITE F, has very strong corrosion resistance at high temperature. Next, the impact resistance and high creep strength, the service life is crucial; rod material is 4Cr9Si2, heat treatment by quenching and tempering, the grain size of 10 - 12, 30 - 40HRC in hardness
