Preparation method of powder metallurgy gear and sprocket

A powder metallurgy and gear technology, applied in the field of powder metallurgy, can solve the problems of increased pressure of re-pressing, increased die loss, etc., and achieve the effects of increasing density, increasing extrusion process, and simple manufacturing process

Active Publication Date: 2017-10-31
LIANYUNGANG DONGMU NEW MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As the pearlite content increases, the pressure of recompression increases, and the die loss also increases

Method used

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  • Preparation method of powder metallurgy gear and sprocket
  • Preparation method of powder metallurgy gear and sprocket
  • Preparation method of powder metallurgy gear and sprocket

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] ① Prepare the raw materials, that is, the mixed powder of iron copper and carbon. The ratio is: atomized iron powder is 96.8%, carbon is 0.70%, copper powder is 2%, and then add lubricant with a content of 0.5%;

[0051] ②Compress the above mixed powder under a pressure of 600MPa to a density of 7.10g / cm 3 tooth (chain) wheel blank;

[0052] ③Sintering, the tooth (chain) wheel parts are sintered at a temperature of 1200°C, the sintering time is 20 minutes, and the sintering is carried out in a vacuum sintering furnace;

[0053] ④Annealing: the annealing temperature is 850°C; the atmosphere is nitrogen, the annealing holding time is 60 minutes, and the cooling rate from the annealing temperature to 300°C after annealing is 0.1°C / S;

[0054] ⑤ Extrusion (finishing): Extrusion is carried out on a press modified by an extrusion molding machine or a finishing press, and the extrusion deformation L2 is (da-d) / 2×8%, while for the internal gear, then L2≥(d-da) / 2×2%, where da ...

Embodiment 2

[0058] ① Prepare the raw materials, that is, the mixed powder of iron, chromium, molybdenum and carbon. The ratio is: iron alloy powder (chromium is 3.0%, molybdenum is 0.5%, other unavoidable substances, less than 1%, iron is the balance) is 50 %, pure iron powder is 48.7%; carbon is 0.8%, and then add lubricant with a content of 0.5%;

[0059] ② Press the above mixed powder under a pressure of 600MPa to form a tooth (chain) wheel green body with a density of 7.2g / cm3.

[0060] ③Sintering, the tooth (chain) wheel parts are sintered at a temperature of 1120°C, the sintering time is 20 minutes, and the sintering is carried out in a sintering furnace based on nitrogen and the proportion of hydrogen is 10vol%;

[0061] ④Annealing: The annealing temperature is 850°C; the atmosphere is nitrogen, the annealing holding time is 60 minutes, and the cooling rate from the annealing temperature to 300°C after annealing is 0.1°C / S.

[0062] ⑤ Extrusion (finishing): Extrusion is carried ou...

Embodiment 3

[0065] ① Prepare the raw materials, that is, the mixed powder of iron, chromium, molybdenum and carbon. The ratio is: iron alloy powder (chromium is 17.0%, molybdenum is 1.0%, other unavoidable substances, less than 1%, iron is the balance) is 99.2 %; carbon is 0.3%, and then add a lubricant with a content of 0.5%;

[0066] ② Warm press the above mixed powder under a pressure of 600MPa to a density of 6.60g / cm 3 tooth (chain) wheel blank;

[0067] ③Sintering, the tooth (chain) wheel parts are sintered at a temperature of 1200°C, the sintering time is 60 minutes, the sintering is carried out in a vacuum sintering furnace, and annealed at 890°C for 60 minutes during the cooling stage after sintering, after annealing The cooling rate from the annealing temperature to 300°C is 0.15°C / S;

[0068] ④ Extrusion (finishing): Extrusion is performed on a press modified by an extrusion molding machine or a finishing press, and the extrusion deformation L2 is (da-d) / 2×5%;

[0069] ⑤Heat...

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Abstract

A method for preparing powder metallurgy gears and sprockets, the steps are: mixing carbon, iron, chromium, molybdenum, copper, and nickel into mixed powder according to the following mass percentages, carbon: 0.1-1.5%, copper: 0-4%, Nickel: 0~5%, molybdenum: 0~2%, chromium: 0.0~18%, no more than 2% unavoidable impurities, iron: the balance; the above mixed powder is pressed on a press with a pressure greater than 400MPa to a density of 6.6 ~7.4g / cm3 tooth (chain) wheel green body; then sintering at 1000℃~1350℃, sintering time is 5~180 minutes; annealing in non-oxidizing atmosphere, annealing temperature 750~1080℃, time 5~ 200 minutes; through extrusion molding machine or finishing press modified on the press for uniform extrusion, the extrusion amount is greater than 2% of the diameter difference between the addendum circle and the dedendum circle; heat treatment is the finished product. The invention has simple manufacturing process, high precision tooth (chain) wheel and good surface finish, reduces production cost and improves production efficiency. Compared with the traditional powder metallurgy process, the product density is higher and the surface densification is basically realized.

Description

technical field [0001] The invention belongs to the technical field of powder metallurgy, in particular to a method for preparing iron-based powder metallurgy gears and sprockets. Background technique [0002] As an important part of the transmission system, the tooth (chain) wheel is traditionally formed by machining. The current main processing methods for machined tooth (chain) wheels include steel forming directly by machining and cold extrusion. The method of mechanical processing has a long process, low utilization rate of raw materials, about 40-60%, high product cost, poor consistency, low production efficiency, and it is difficult to meet the requirements of good consistency in large quantities. [0003] And adopt the method of cold extrusion to form, generally need warm forging billet, then cold extrusion forming. Forgings have high dimensional accuracy, good dimensional consistency, smooth surface, high tooth profile accuracy of internal gear, clear gear outline...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/20B22F5/08B22F1/00C22C38/08C22C38/12C22C38/16C22C38/18C22C38/20C22C38/22
Inventor 包崇玺毛增光詹学救蔡立山
Owner LIANYUNGANG DONGMU NEW MATERIALS CO LTD
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