High-frequency induction heating machine manufacturer explains the heat treatment of Ferro-TiC cutting tools

Ferro-TiC steel-bonded cemented carbide is a new tool material made with TiC as the hard phase, high-speed steel or alloy steel as the bonding phase, and using the powder metallurgy liquid phase sintering method. It has both cemented carbide and tool steel. It has the characteristics of high hardness, high wear resistance, high strength and sufficient toughness, and can be processed in cold and hot processes, so it has broad application prospects.

With the rapid development of science and technology and the need for opening up to the outside world, the knife market is quite active. "Nylon knives" for cutting polyethylene and other plastic products have been introduced from abroad. They were also successfully developed domestically in the 1990s and put into mass production. Nowadays, The heat treatment process of "Nylon Knife" is introduced as follows.

1) Heat treatment of M-6 steel alloy.

①Composition of alloy. The weight ratio of hard phase and binder phase is 30:70.

②Performance requirements.

③ Solid solution treatment. Solution treatment, also known as solution annealing, is to heat the alloy to 810-820℃. The heating and holding time of the salt bath furnace is calculated as 1.25-1.50min/mrn. The heating time of air furnaces such as box-type furnaces should be appropriately extended, and corresponding measures should be taken. To prevent oxidation and decarburization, air cooling should be carried out after being released from the oven.

The heat preservation time must be sufficient to fully dissolve the matrix components and form a single structure. After rapid cooling, the matrix can form a single supersaturated solid solution.

After solution treatment, the ductility of the alloy is greatly improved, the hardness is in the range of 48-52HRC, and high-speed steel tools can still be used for various cutting processes.

④ Aging treatment. Aging treatment, also known as precipitation hardening, dispersion hardening, precipitation hardening or age hardening, is to treat the non-equilibrium single-phase supersaturated structure obtained after solid solution treatment at 477 -48TC x3 -4h, so that the second phase particles are dispersed and precipitated, thereby achieving Hardening purpose. After aging according to the above specifications, the hardness is around 62HRC, with a minimum of 60.5HRC, which meets the technical requirements.

2) Heat treatment of chromium-molybdenum steel-based steel alloy.

annealing. Generally, a high-frequency induction heating machine is used. After treatment at 860-880℃x3-4h, it is cooled to 720-740℃ at a low cooling rate of 20℃ and kept for 4-5h. The furnace is cooled to below 500℃ and air-cooled. After annealing) the metallographic structure is TiC+ spherical pearlite, with a hardness of 38-44HRC.

Back quenching and tempering. During the heating and cooling process, TiC does not change, so the purpose of quenching is to turn the matrix into martensite to improve hardness, strength and wear resistance. Therefore, the quenching heating temperature should consider the full austenitization of the matrix. The heating temperature The higher the temperature, the better the austenite uniformity and alloying degree, but too high a temperature will make the martensite grains coarse, which is detrimental to the comprehensive mechanical properties, and too low a heating temperature is not advisable.

According to the experience of Zhengzhou Gou's electromagnetic induction heating equipment manufacturer, the temperature of the quenching oil is preferably controlled at 60-90°C. The metallographic structure after quenching is quenched martensite + TiC + retained austenite.

Tempering should be carried out in time after quenching to eliminate internal stress, improve toughness, stabilize the structure, and obtain the required comprehensive properties. Tempering specification: 350 -380℃x90 - 120min.