1. The annealing temperature is generally 860~880℃. Quenching is generally performed in two stages due to its poor thermal conductivity. First preheat at 800~850℃ (to avoid causing large thermal stress), then quickly heat to the quenching temperature of 1220~1250℃, and then oil cool.

2. After quenching, some (about 30%) retained austenite remains in the internal structure and has not transformed into martensite, which affects the performance of high-speed steel. In order to transform the retained austenite and further improve the hardness and wear resistance, tempering is generally performed 2 to 3 times at a tempering temperature of 560°C and heat preservation for 2 hours each time.

High-speed steel heat treatment generally uses quenching and tempering processes to improve material hardness and cutting performance.

1. Quenching treatment
Quenching is one of the most commonly used heat treatment methods in high-speed steel materials. The quenching process transforms austenite in high-speed steel materials into hardened structures through rapid high-temperature heating to improve material hardness and cutting performance.
For different types of high-speed steel materials, the quenching heating temperature and holding time will also be different. For example, for high-speed tool steel W18Cr4V, the quenching heating temperature is generally between 1240°C and 1280°C, and the holding time is 5-7 minutes.
However, it should be noted that the cooling rate needs to be strictly controlled during the quenching process. If the cooling rate is too fast, it will cause stress on the surface and inside the high-speed steel material, causing cracks and deformation. Therefore, the temperature and speed of the cooling medium need to be controlled during the quenching process to ensure the cutting performance and stability of the material.

2. Tempering treatment
Tempering is a heat treatment process performed after quenching high-speed steel in order to eliminate the internal stress generated during the quenching process and improve the toughness of the material. The tempering temperature and holding time are generally lower and longer than quenching to avoid the high-speed steel material from producing a large amount of martensite structure, which will affect the material's toughness and fatigue resistance.
For different types of high-speed steel materials, tempering temperatures and times will vary. For example, for high-speed tool steel W18Cr4V, the tempering temperature is generally between 550°C and 600°C, and the holding time is 2-3 hours.
In addition to quenching and tempering, the heat treatment of high-speed steel materials may also include annealing, normalizing, quenching (quenching) and other processes. However, no matter what heat treatment method is used, the heating temperature and cooling rate need to be strictly controlled to ensure the quality and cutting performance of high-speed steel materials.

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