Manufacturing process of chain wheel for chain saw

Abstract

The manufacture process of chain wheel for chain saw includes the following steps: powder metallurgy process to produce gear blank with sorted materials; precise forging through soaking graphite milk or coating graphite or setting in nitrogen protection, fast induction heating to 815-950 deg.c for less than 20 sec, fast forging in closed mold and demolding to reach gear density greater than 7.7 g / cu cm; assembling the gear to hub; and brazing and hardening in the protection of nitrogen with small amount of hydrogen inside a brazing furnace with fast cooling gas system for gas quenching to harden through phase change to reach hardness over HRC58. The manufacture process is simple, and has high production efficiency, low cost and high product precision and quality.

Description

technical field [0001] The invention belongs to the technical field of mechanical manufacturing, in particular to a method for manufacturing a chain saw chain wheel. Background technique [0002] The chain saw sprocket is an important part of the chain saw, and its function is to drive the saw chain to cut wood. The sprocket is generally assembled and welded by the sprocket gear and the hub. The traditional sprocket gear manufacturing technology is machined by mechanical processing. Machining low-carbon low-alloy steel cold punched or cold-extruded gear blanks with gear profiles, and then completing carburizing heat treatment; the hub of the sprocket is generally completed by stamping. The materials of the gear and the hub are different, and the gear material is low carbon. Low alloy steel, for example: 17CrNi6; hub material is 25CrMo4. [0003] The assembly process of the sprocket is as follows: the gear is assembled with the hub after carburizing heat treatment → brazin...

AI Technical Summary

Problems solved by technology

[0006] 1. The cycle of cold stamping, cold extrusion and machining of gear blanks is long, the efficiency is low, and the cost is high;

[0007] 2. Two-step heat treatment is required in the manufacturing process of the sprocket (carburizing heat treatment is required after gear processing; hardening heat treatment is required after brazing), which is costly and increases the deformation caused by heat treatment, especially after the sprocket and hub are brazed. Causes a lot of deformation; and because the materials of the gear and the hub are different, in order to ensure the quality, the atmosphere of the heat treatment needs to be strictly controlled

[0008] 3. Although the existing ordinary powder metallurgy manufacturing method improves the production efficiency, due to the limitation of its gear components, the gear blank has not been precision forged in a closed chamber, the gear density is low, and the performance is difficult to compare with the machined gear

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