When the worm uses a forged blank, the ingot forging ratio is generally not less than 3, and the forging ratio is generally not less than 1.5. The material is generally selected from 35CrMo steel, and its chemical composition, mechanical properties and hardness requirements should meet the requirements of GB3077. Other materials with mechanical properties and hardness not lower than 35CrMo, such as 42CrMo, 38CrMoAl, and carburizing steel, are allowed. Before the precision machining of the tooth surface, it should be hardened. After finishing, the hardness of the tooth surface is not lower than HV500, and the roughness of the tooth surface Ra≤0.8μm.
The worm wheel flange material is generally made of cast tin bronze ZCuSnlOPI. Castings are not allowed to have defects such as segregation, inclusions, shrinkage, looseness, cracks, etc. The chemical composition, mechanical properties and hardness of the castings shall comply with the provisions of GB 1176. When the sliding speed is less than 5m / s, the cast aluminum bronze ZCuAllOFe3 specified in GB 1176 can be used. Other materials with equivalent performance are allowed, and the surface roughness Ra≤1.6μm. Allow traces of trauma on the tooth surface.
The worm gear shaft is made of 45 steel or other material with equivalent mechanical properties. Its chemical composition and mechanical properties should meet the requirements of GB 699 and other corresponding standards.