35CrMo steel (quenched and tempered) non-metallic inclusions

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35CrMo steel is a alloy structure steel. It is used after quenching and tempering and has high strength and toughness. It is mainly used for manufacturing important parts with large section and complex shape and other parts which are required to have good impact resistance and size stability. 35CrMo alloy steel has great rigidity, fatigue strength, yield strength and high heat resistanc, which .

35CrMo Steel Chemical Composition, Mechanical Properties .

35CrMo Steel. 35CrMo steel is a Chinese alloy steel for engineering purpose, it has high durability and creep strength at high temperature, and low temperature impact toughness is good. The working temperature is up to 500 °C, the low temperature can be -100 °C, and has high static strength and high fatigue strength, good hardenability.

35CrMo alloy steel (35CrMo, SCM435) is a kind of alloy steel containing chromium and molybdenum elements, which has higher hardenability and better comprehensive performance than 40Cr (AISI4140, G41300). It is often used in the manufacture of automobile powertrain parts such as gears, shafts, and connecting rods, and medium and heavy load bearing parts such as pins and shafts.

35CrMo alloy steel contains about 0.32-0.4% C, 0.9-1.2% Cr, 0.17-0.37% Mo, less than 0.030 % S, and less than 0.030 % P. The chemical composition of the material has a great influence on the hardness, toughness, plasticity and cold deformation of the alloy steel. The addition of molybdenum can effectively improve the temper brittleness of the steel, while increasing the hardenability and tempering stability of the steel.

The tempering temperature of 35CrMo alloy steel is generally between 300℃ - 600℃. The tempering temperature should be properly selected according to the mechanical properties of the material and its use requirements. The tempering temperature is generally about 500℃. A certain degree of cooling induced transformation can improve the dynamic and static performance and the thermal fatigue strength of the material.

35CrMo alloy steel has good plasticity and toughness in the annealed state, but its strength is relatively low. The heat treatment of 35CrMo alloy steel is usually tempered after quenching. The mechanical properties are good due to its high hardenability and uniform hardening performance. After tempering, its strength and toughness are also good, and its weldability is generally good.

The non-metallic inclusions in 35CrMo alloy steel generally exist in the form of Al2O3, SiO2, MgO, MnS and MnO, and need to be strictly controlled. For example, Al2O3 should be less than 0.02%, CrO should be less than 0.03%, and MgO should be less than 0.02%. Non-metallic inclusions should be within the prescribed range during production and processing, and appropriate measures should be taken to adjust and optimize the chemical composition, heat treatment process and forming process.