Maximum hardness of 40Cr heat treatment

Quenching process

40Cr quenching 850 ℃, oil cooling; tempering 520 ℃, water cooling, oil cooling. The quenching hardness of 40Cr surface is hrc52-60, and the flame quenching can reach hrc48-55.

The hardness is related to the carbon content. The higher the carbon content is, the higher the hardness is.

40Cr normal quenching hardness hrc47 ~ 50.

The hardness of 40Cr 840-860 ℃ quenching oil can reach hrc52-56.

Induction hardening can achieve HRC60 or so.

40Cr characteristics:

Medium carbon steel, cold heading die steel. The steel has the advantages of moderate price, easy processing and certain toughness, plasticity and wear resistance after proper heat treatment. Normalizing can promote the spheroidization of the structure and improve the cutting performance of the blank with hardness less than 160hbs. Tempered at 550 ~ 570 ℃, the steel has the best comprehensive mechanical properties. The hardenability of the steel is higher than that of 45 steel. It is suitable for high frequency quenching, flame quenching and other surface hardening treatment.

40Cr purpose:

After tempering, the steel is used to make mechanical parts that can bear medium load and medium speed, such as steering knuckle, rear axle, shaft, worm, spline shaft, top sleeve, etc;

After quenching and tempering at medium temperature, it is used to manufacture parts that bear high load, impact and medium speed, such as gears, spindles, oil pump rotors, sliders, collars, etc;

After quenching and low temperature tempering, it is used to manufacture parts with heavy load, low impact, wear resistance and solid thickness of less than 25 mm on the section, such as worm, main shaft, shaft, lantern ring, etc;

After tempering and high frequency surface quenching, it is used to manufacture parts with high surface hardness and wear resistance without great impact, such as gear, sleeve, shaft, main shaft, crankshaft, mandrel, pin, connecting rod, screw, nut, intake valve, etc.

In addition, the steel is suitable for manufacturing all kinds of transmission parts, such as gears and shafts with large diameter and good low temperature toughness.