Are gears case hardened?

There are several methods of case hardening for gears, including vacuum carburizing, atmosphere carburizing, and induction hardening. Each process produces a variety of case depths and varying degrees of hardness. Whichever process you rely on depends on how much or how little you need to harden.

What is the level of hardness that can be expected for gear teeth that are case hardened by flame or induction hardening?

The usual range of carbon content required in gear steels for flame hardening is 0.40–0.50%. Quenching is done either by water spray or by air. A typical hardness range for various compositions of gear steels obtained by water quenching is 45–65 HRC, and by air quenching is 45–63 HRC [1].

Why is case hardening of gear teeth necessary?

Single Tooth Hardening: Single tooth hardening is primarily used to induction heat treat gear teeth to improve strength and wear characteristics. The process is accomplished by hardening one tooth root at a time.

What is the case depth of carburized steel?

Carburizing is a surface hardening treatment that produces a hard, wear-resistant layer (case) on the part surface. Case depth can range from as low as 0.010″, to as deep as 0.200″. Surface hardness can be as high as 62 – 64 HRC.

What are the disadvantages of case hardening?

The main drawback of this hardening process is the depth of hardness is not uniform and cannot be controlled easily. In this process the steel material is heated to a temperature of around 5500C and then exposed to atomic nitrogen.

How are gear teeth hardening?

Depending on the gear size, required hardness pattern and geometry, gears are induction hardened by encircling the whole gear with a coil (so-called “spin hardening of gears”), or for larger gears, heating them “tooth-by-tooth”, where a more precise hardening result can be achieved, although the process is much slower.

What is the Rockwell hardness of case hardened steel?

Case-hardening produces a hard, wear-resistant case, or surface layer (to increase pitting resistance and bending strength) on top of a ductile and shock-resistant interior also known as core, of hardness 30–40 HRC to avoid tooth breakage [1].

How hard is case hardened steel?

0.8%. The surface hardness and the properties of the core are obtained by hardening and tempering. This process leads to a hard, wear-resistant surface layer, while the core is comparatively tough, which enables the steel to withstand impact stresses without fracture and lends it a high resistance to wear.

Is carburizing the same as case hardening?

Carburizing, also referred to as Case Hardening, is a heat treatment process that produces a surface which is resistant to wear, while maintaining toughness and strength of the core. This treatment is applied to low carbon steel parts after machining, as well as high alloy steel bearings, gears, and other components.

What is the depth of case hardening?

The Case Hardness Depth (Chd) is derived from the curve representing the hardness in dependance of the distance from the edge of the specimen surface (edge distance) by measuring the edge distance up to a limit hardness of 550 HV or the corresponding Knoop hardness value.

What steels can be case hardened?

What Types of Metals Can Be Case Hardened?

  • Low carbon steel.
  • High carbon steel.
  • Cast iron.
  • High strength low alloy steel.
  • Tool steel.
  • Stainless steels.