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Hardening of gears
  • Hardening of gears

Hardening of gears

Our gear hardening machine adopts the principle of induction heating. It has fast heating speed and uniform heating depth. When used for gear hardening, after hardening, the hardness of the gear is uniform, the brittleness is small, the surface of the gear is not easy to be oxidized and decarburized, and the gear deformation is small.
Induction hardening of general steel gears, the carbon content of steel is between 0.3% -0.7% (hypoeutectoid steel).
Our technical team determines the power and frequency of the induction hardening machine according to the depth, hardness and speed requirements of the gear hardening, and determines the size of the induction coil according to the diameter and thickness of the gear.
Gear hardening technology is widely used in the automotive parts manufacturing industry. Our gear hardening machine can be used for hardening of spur gears, helical gears, herringbone gears, bevel gears, disk gears, shafts, rack gears, etc.

Advantages of gear Hardening machines:
  • It is possible to harden specific parts of metal workpieces, such as hardening of the section of the workpiece.
  • It can control the heating temperature and set the heating time.
  • It can control the cooling time.
  • It can realize automatic hardening and improve production efficiency.
  • The entire process of hardening is completely completed by the machine, and the position, temperature and time of hardening are more accurately controlled.

Our hardening machine can complete the induction heating Hardening process in two ways:
  1. Static Hardening. Place the metal workpiece in the induction coil and perform the hardening operation without moving the workpiece and the induction coil. This hardening method is very fast and the mechanical structure is simple. Even if the geometry of the workpiece is very complex, it can be positioned very accurately at the position to be quenched.
  2. Progressive Hardening. It is also called scanning hardening. During the heating process, the workpiece or the induction coil is always moving. This Hardening method is suitable for Hardening of workpieces with large surface areas. Compared with the static Hardening method, the power of the machine used for scanning Hardening is lower, but the hardening process takes longer.
Gear Hardening can be divided into the following types:
  • Overall hardening of small modules and small diameter gears.
  • Scan hardening of large modules and large diameter gears.
  • Hardening of tooth surface
  • Hardening of tooth root.

Gear hardening method description
Molde Hardening of gear surfaces and roots Hardening of gear surface
Hardening method Overall Hardening Single tooth moving Hardening Single tooth moving Hardening Single tooth Hardening
Feature Wear resistance,
Tooth surface pressure resistance
High tooth strength
Wear resistance, 
Tooth surface resistant to high pressure
Feature The entire tooth has a uniform hardened layer
High gear teeth are strong
Large degree of Hardening freedom
Less deformation than overall Hardening
High gear tooth strength
Small power capacity
Small deformation
High tooth surface strength
Hardening easy
Small deformation
High tooth surface strength
Hardening easy
Application High load, small and medium modulus
Spur gear
Bevel gear
High load, large and medium modulus
Spur gear
Helical gear
Low load, large and medium modulus
Spur gear
Helical gear
Low load, small modulus
Hyperbolic gear
Plane gear
Wide gear
Hardening range Nichrome m≤25
Carbon steel m≤10
7≤m≤36 5≤m≤60 m≤6

Reference table for surface hardness and hardened depth of various workpieces
Material Tooth surface hardening Hardening of gear surfaces and roots
/ Hardness
Gear surface hardness
Gear surface depth
Gear root hardness
Gear root depth
35 60-70 ≥1.5(50) 60-70 ≥1.5(50) ≥50 ≥1.5(45)
45 60-75 ≥2.0(55) 60-75 ≥2.0(55) ≥55 ≥1.5(50)
35CrMo 60-73 2-5(≥55) 60-73 2-4(≥55) ≥60 2-3(≥55)
40CrMo 60-75 2-6(≥55) 60-75 2-4(≥55) ≥60 2-4(≥55)
30CrNi3A 60-73 2-5(≥50) 60-73 2-4(≥50) ≥60 2-3(≥48)
40CrNiMoA 60-75 2-6(≥55) 60-75 2-5(≥55) ≥60 2-4(≥55)
SCC3# 60-70 ≥2.0(55) * * * *
SCMn2# 60-70 ≥2.0(48) * * * *