Why do we Case harden gears?
Case-hardened gears provide maximum surface hardness and wear resistance and at the same time provide interior toughness to resist shock. The thickness of the hardened layer should be such that it can withstand the maximum contact stress without collapsing into the softened core of the gear-tooth.
What are the factors needed for case hardening?
The result of the hardening process is controlled by four factors:
- Design of the flame head.
- Duration of heating.
- Target temperature to be reached.
- Composition of the metal being treated.
Can you undo case hardening?
The only way to rid any steel of case hardening is to run it thru a heat cycle. All tempering or annealling is a process of heating and cooling the steel…. some require the use of oil cooling or controlled rate heating and cooling.
Is induction hardening a case hardening?
Case hardening process used to increase wear resistance, surface hardness and fatigue life through creation of a hardened surface layer while maintaining an unaffected core microstructure. Induction hardening is used to increase the mechanical properties of ferrous components in a specific area.
How do you harden gears?
The basic procedure for hardening a steel part is to heat it until the crystal structure changes at the atomic level. The part is then cooled rapidly by quenching to form a crystal structure that is much more resistant to deformation than the unhardened steel. This results in greater hardness and strength.
What is the difference between case hardening and full hardening?
The main difference between case hardening and surface hardening is that case hardening increases the hardness of the surface of the metal by infusing elements into the materials surface, forming a thin layer of harder alloy whereas surface hardening increases the hardness of the surface while the core remains …
What is the hardening process?
Case hardening is the process of hardening the surface of a metal by infusing elements into the material’s surface, forming a thin layer of harder alloy. Combined with a subsequent hardening operation the desired component properties can be varied to suit the application.
What is high in induction hardening?
In induction hardening ________ is high. Induction hardening is a type of surface hardening in which a metal part is induction-heated and then quenched. The quenched metal undergoes a martensitic transformation, increasing the hardness and brittleness of the part. In induction hardening Frequency is high.
Is tempering required after induction hardening?
Parts may be Tempered after Induction Hardening to Adjust Hardness Level, as desired. As with any process producing a martensitic structure, tempering will lower hardness while decreasing brittleness.
Which surface hardening process is capable of producing the hardest case?
Nitriding is one of the most widely used processed in surface hardening. What are the advantages of the nitriding process? 1. Produces the hardest case out of all the surface hardening methods.
What is case hardened in law?
Definitions of case-hardened. adjective. used of persons; emotionally hardened. “faced a case-hardened judge” synonyms: hard-boiled, hardened hard.
Which is the best way to harden a gearbox?
Gears may be through-hardened, meaning the entire gear reaches the same hardness all the way through. High toughness may be obtained by hardening only the surface of the gear to a depth that provides sufficient surface hardness, while leaving the remainder in a relatively softer state.
How does induction hardening affect the accuracy of gears?
For gear products, induction hardening is effective to harden tooth areas including tooth surface and the tip, however, the root may not be hardened in some cases. The precision of gears declines by induction hardening. To encourage the gear accuracy, grinding must be applied.
How is the toughness of steel gear obtained?
High toughness may be obtained by hardening only the surface of the gear to a depth that provides sufficient surface hardness, while leaving the remainder in a relatively softer state. Such surface hardening also allows the use of less expensive steels and less costly heat treating methods.
How big is the depth of gear hardening?
The depth of hardening is usually limited to 0.050 inch or less, due to the time required for carbon to diffuse deeply into the gear. Once hardened, gears are then inspected and shipped to the gear reducer manufacturer for installation.
What’s the name of the hardened layer in gears?
The hardened layer is called the case. The thickness of the hardened layer is referred to as the case depth. There are several methods of case hardening for gears, including vacuum carburizing, atmosphere carburizing, and induction hardening.
What is the purpose of case hardened gears?
Case-hardened gears provide maximum surface hardness and wear resistance and at the same time provide interior toughness to resist shock. The thickness of the hardened layer should be such that it can withstand the maximum contact stress without collapsing into the softened core of the gear-tooth.
Gears may be through-hardened, meaning the entire gear reaches the same hardness all the way through. High toughness may be obtained by hardening only the surface of the gear to a depth that provides sufficient surface hardness, while leaving the remainder in a relatively softer state.
How does case hardness affect a gear tooth?
While an excessively hardened depth may make the gear-tooth too brittle to withstand tensile stresses, the exact required value of the case depth depends on the gear-tooth form and the application requirements. The major case-hardening processes include nitriding, carburizing and their combinations, e.g., nitrocarburizing.