Quenching treatment of steel materials

It is to heat the steel to the quenching temperature, hold it for a period of time, and then rapidly cool it in water, brine or oil (individual materials are in air). The purpose is to obtain higher hardness and wear resistance of steel parts. Make the steel parts get some special properties after tempering, such as higher strength, elasticity and toughness.

(1) Single-liquid quenching

The steel is heated to the quenching temperature and, after holding, is cooled in a quenching agent.

Single-liquid quenching is only suitable for carbon steel and alloy steel parts with relatively simple shapes and low technical requirements. During quenching, for carbon steel parts with a diameter or thickness greater than 5-8mm, use brine or water cooling; for alloy steel parts, use oil cooling.

(2) Double liquid quenching

The steel is heated to the quenching temperature, and after heat preservation, it is rapidly cooled in water to 300-400ºC, and then transferred to oil for cooling.

(3) Flame surface quenching

The flame of the mixed combustion of acetylene and oxygen is sprayed onto the surface of the part, so that the part is rapidly heated to the quenching temperature, and then water is sprayed to the surface of the part immediately.

Flame surface quenching is suitable for single-piece or small-batch production, large-scale medium-carbon steel and medium-carbon alloy steel parts that require hard and wear-resistant surfaces, and can withstand impact loads, such as crankshafts, gears and guide rails, etc.

(4) Surface induction hardening

Put the steel part in the inductor, the inductor generates a magnetic field under the action of alternating current of a certain frequency, and the steel part generates an induced current under the action of the magnetic field, so that the surface of the steel part is rapidly heated (2~10min) to the quenching temperature, then immediately spray water onto the surface of the steel.

The surface induction hardened parts are hard and wear-resistant on the surface, while the interior maintains good strength and toughness. Surface induction hardening is suitable for medium carbon steel and alloy steel parts with medium carbon content.