QT400-10 nodular cast iron requires hardness of HRC47~51. Why can't quench hardness be reached?
Because of the high tempering stability of the nodular iron, the tempering temperature is 400-450 degrees, and the tempering time is 1 hours.
Quenching temperature: when the silicon content of nodular cast iron is 2.0-3.0%, the quenching temperature is 860-900 DEG C, the silicon content is low, and the upper limit is taken when the lower limit is high.2. holding time: because of the consideration of diffusion graphite cast iron, alloy steel is therefore the holding time, holding time longer than carbon steel.3. oil quenching.
QT400-10 shall ensure sufficient pearlite in the casting state, at least half of the pearlite. This is done with the temperature, time, and water. But if it is big, the heart hardness will not go up.
