1. Standardising
The steel is heated past its critical temperature, kept at that temperature for a while, then taken out of the furnace to undergo air cooling.
Aim:Normalising is usually replaced for steel components with less than 0.5% carbon content by annealing; b. improve the low carbon steel cutting efficiency; c. Improve the strength and hardness and change the grain structure; d. Normalising is usually seen as the last resort for gear components without high mechanical quality.
2. Annealing Treatment
Raise the steel to the suitable temperature, keep it at that temperature for a while, then let it cool gradually.
Goals: a. improve homogeneity of structure, grain quality, and mechanical properties of steel; b. Reduce the internal conflict the previous step created; b. Get ready for the later heat treatment; d. Improve plasticity and hardness.
3. After quenching
It is tempered at a high temperature between 450 and 650 degrees Celsius.
Goal: To achieve perfect elimination of inner tension and provide outstanding mechanical properties.
4. Cyanidation Treatment
Carbon and nitrogen atom simultaneous penetration into the surface of a steel component
Goal: Improve gear surface's hardness, corrosion resistance, fatigue strength, and wear resistance.
5. Nitrogen diffusion treatment
Permeating nitrogen atoms into the surface of a steel component is the nitrogenriding treatment.
Goal: Improve gear surface's hardness, corrosion resistance, fatigue strength, and wear resistance.
6. Surface Quenchning Method
Quickly raise the surface temperature of the steel above the critical threshold using high-frequency current or flame, then fast cool.
The gear's core maintains its natural toughness and flexibility while the surface shows increased hardness, therefore guaranteeing wear resistance and ability to withstand specified impact loads.
7. Quenching Treatment
Increase the temperature of the steel over the critical level for a while then fast cool it.
Goals: improve wear resistancea Boost durability and hardness.
8. Quenching and carburation treatment
Heated in a carburising medium between 900 and 950 degrees Celsius, kept for a while, then quenched and temperated.
Goal: a. The gear teeth' central core has specific hardness; b. Improve the component surface wear resistance and hardness; b. Increase the fatigue ultimate strength of the component.
The intrinsic quality of gear teeth is directly determined by heat treatment of gears; so, the quality of the process will directly influence the strength, accuracy, noise level, and lifetime of the product. Manufacturing depends on tooth form and finishing after heat treatment, which also reflect the quality of gear manufacture.
Although this book presents the accepted methods of heat treatment for gears, knowledge of gear heat treatment goes beyond this general picture. Please feel free to get more information by contacting our experts.