With the expansion of the scale of cement production, the specification of cement rotary kiln also increases. The girth gear is one of the important components of the rotary kiln, and its diameter and weight also rise (such as the the 4.8m * 72m rotary kiln girth gear by CHAENG (Great Wall Steel Casting) can reach 32t weight). The girth gear deformation problems often appear during operation of the rotary kiln.

CHAENG girth gear has the advantages of high hardness, strong impact resistance and deformation resistance. Why CHANEG girth gear can have the ability to prevent deformation? Let's find the answers from  forefront of production.

Aiming at the common deformation problems, CHAENG optimizeds innovative casting process based on traditional process. The improved process is practical and effective to control deformation problem and increase service life of girth gear.

There are three weakpoints of traditional process:

1. After rough machineing, the internal stress of the big gear can not be eliminated because of the non-aging treatment. Deforamtion problem exist the whole process.

2. Fine milling doesn't polish the half surfaces. The stress deformation and insufficient CNC machine orecision result in big clearance between two half surfaces.

3. Tooths of large module gears or large profile shifted gears are not completed.

Great Wall Steel Casting adds the following 5 procedures:

1. Coarse hobbing.

Eliminate part of casting stress, and shorten the precision on hobbing machine, to improve work efficiency.

2. Flaw detection.

Conduct flaw detection for girth gear after rough machining and rough hobbing, to check if there are gasholes, sandholes or cracks.

3. Special lengthened hob.

Adopt special lengthened hob to perform hobbing for large module and large  profile shifted gears to complete the tooths.

4. Annealing treatment.

Use annealing treatment to eliminate internal stress produced by casting and rough machining process, and repair welding stress to avoid deformation.

5. Customize and optimize according to actual operation situation and demands.

Great Wall use high-strength steel to cast girth gear and optimized the girth gear base on operation characteristics of rotary kiln, to guarantee girth gear's stability and prevent deformation caused by rotating stess.

Great Wall Steel Casting provide every specification according to customers's drawings:
Weight: 10-35t
Diameter: larger than 2m
Material: Carbon & alloy steel