What is the heat treatment process of 45# steel plate?

Delivery status of 45# steel plate: normalizing, tempering, quenching and tempering.
Normalizing N: the steel plate is heated to an appropriate temperature and cooled in the air;
Tempering T: the steel plate is kept at an appropriate temperature for a long time before cooling;
Quenching Q is to heat the steel plate and heat preservation and rapid cooling in the medium of water, oil or other inorganic salts; Modulation: N+T normalization and tempering;

45# steel plate after quenching without tempering, the actual application of the highest hardness HRC55 (high-frequency quenching HRC58). 45# steel plate should not be carburized quenching heat treatment process.