Method for producing bevel gear with ratchet on end face through powder metallurgy warm forming

Abstract

The invention discloses a method for producing a bevel gear with ratchets on an end face through powder metallurgy warm forming. The method comprises the following steps of: preparing iron powder, copper powder, nickel powder, molybdenum powder, graphite powder and a warm forming special lubricant into a mixer to mix according to a proportion; filling in a heated mould; preparing a compact under the condition of unit pressing pressure of 6.5-7.5 T / cm<2> and density of reaching 7.2-7.3 g / cm<3>; placing the compact in a sintering furnace and sintering in a protective atmosphere of mixed gas of hydrogen and nitrogen at 1,120 DEG C for 40 minutes; nitrocarburizing the sintered compact in a carbon and nitrogen atmosphere of 850 DEG C in a controllable atmosphere thermal treatment furnace for 60 minutes; quenching at 850 DEG C; oil-cooling at a cooling speed of 110 DEG C / 10 minutes; tempering at 180 DEG C for 1 hour to machine an inner hole on a precision numerical control lathe to dimensional requirements through tooth shape positioning; finishing; removing thermal treatment oil stain and surface burrs; cleaning; drying; and soaking anti-rust oil to prepare a finished product. The method has the advantages of high product consistency, capability of meeting requirements of large-scale stable production, particular suitability for producing the bevel gear of high accuracy, high strength and high difficulty.

Description

technical field [0001] The invention relates to a method for producing a helical gear with a ratchet on the end face by a powder metallurgy warm mold, and belongs to the technical field of gear manufacturing and complex structural parts processing. Background technique [0002] Most of the existing high-density, high-strength helical gears with ratchets on the end face are imported powder metallurgy parts and domestically processed components, and powder metallurgy methods are also used in domestic production, but the products produced have the following shortcomings: [0003] 1. Cold forming, low pressing density, density 6.8-7.0 g / cm 3 . Material performance does not meet the requirements, poor strength, low single-tooth resistance, poor impact resistance, and prone to tooth collapse; [0004] 2. Warm pressing, pressing density can be pressed to 7.2-7.3 g / cm 3 , Although the material properties can meet the requirements, the hopper, feeding pipe, material shoe, upper an...

AI Technical Summary

Problems solved by technology

[0003] 1. Cold forming, low pressing density, density 6.8-7.0 g / cm 3

The material performance cannot meet the requirements, the strength is poor, the single tooth has low resistance, the impact resistance is poor, and the problem of tooth collapse is easy to occur;

[0004] 2. Warm pressing, pressing density can be pressed to 7.2-7.3 g / cm 3 , Although the material properties can meet the requirements, the hopper, feeding pipe, material shoe, upper and lower molds, and mold cavity must be heated during temperature pressing, and expensive special lubricants for temperature and pressure must be added to the powder, which has low efficiency and high process cost;

[0005] 3. The ratchet part and the helical part of the machined parts should be processed separately, and then riveted and combined into one, the material utilization rate is low, the efficiency is very low, the processing cost is high, the gear consistency is not good, the precision is poor, and the batch is unstable