The following are the main steps and precautions for casting large gear rings in our company:
1. Material selection
Common materials: Large gear rings are usually made of high-strength alloy steel or cast steel, such as ZG310-570, ZG42CrMo, etc. The specific material selection depends on the working environment and load requirements.
Material properties: The material needs to have good wear resistance, impact resistance, and fatigue resistance.
2. Casting process
Model making: Make wooden or metal molds according to the design drawings to ensure dimensional accuracy.
Sand casting: The commonly used sand casting process involves selecting appropriate molding sand (such as resin sand, sodium silicate sand, etc.) to ensure the surface quality and dimensional accuracy of the castings.
Melting and pouring: Melting molten steel in an electric furnace or a blast furnace, strictly controlling the temperature, and avoiding defects such as porosity and slag inclusion during pouring.
Cooling and Cleaning: Slowly cool after pouring to prevent stress cracks, clean the surface of the casting after cooling, and remove sprues and burrs.
3. Heat treatment
Annealing: Eliminating casting stress and improving tissue uniformity.
Normalization and tempering: Improve the hardness and wear resistance of the gear ring, and the specific process is determined according to the material and requirements.
4. Mechanical processing
Rough machining: Turning the outer circle, inner hole, and end face, leaving a margin for precision machining.
Precision machining: using CNC machine tools for tooth profile machining to ensure tooth profile accuracy and surface smoothness.
Grinding teeth: Grinding teeth when necessary to further improve accuracy.
5. Testing and Quality Control
Dimensional inspection: Use tools such as coordinate measuring instruments to measure dimensional accuracy.
Hardness testing: Ensure that the hardness of the gear ring meets the requirements.
Non destructive testing: internal defects are detected by ultrasonic or magnetic particle testing.
6. Surface treatment
Surface quenching: Improve the hardness and wear resistance of the tooth surface.
Coating treatment: such as chrome plating, nitriding, etc., to enhance corrosion resistance and wear resistance.
7. Assembly and Debugging
Assembly: Assemble the ring gear onto the equipment, ensuring good meshing with the gear.
Debugging: Conduct no-load and load debugging to ensure smooth operation and no abnormal noise.
8.Precautions
Process control: Strictly control the casting and heat treatment processes to prevent deformation and cracking.
Equipment selection: Use high-precision machining equipment to ensure tooth profile accuracy.
Quality inspection: Strictly inspect every step to ensure final quality.
