| Product name | Mill ring |
| Material | Alloy steel |
| Standards/Certificates | UNI EN ISO, AWS,ASTM,ASME,DIN |
| Apply to | Vertical mill |
| OEM service offered | According to customer’s drawings |
With more than 1000 girth gears sold over the world CITICIC Gear is a leading supplier in the cement and mineral industry. And as member of AGMA (American Gear Manufacturers Association), we do actively take part in defining the standard for gear rating calculations and service factors.
We provide girth gears in three different designs
Fabricated steel
- forged ring
- rolled plate
Cast steel
Ductile (Nodular) cast iron
Fabricated gears became more common in the past and are constructed with forged steel gear rim materials and electro welded body structure. The rings are manufactured from a whole block of high resistance alloy steel. After the rough machining of the ring, we carry out hardening and tempering heat treatment in order to improve the mechanical characteristic and therefore its relevant performance.
Avantages of fabricated girth gears
The forged material structure excludes the risk of inclusions
Structure defects like gas holes, micro shrinkage, pin holes, hot tears, sand and slag inclusions are avoided Hence, repair welding of the body structure and e.g. grinding of toothed areas is not required.
The fabricated manufacturing procedure excludes the need for patterns and risers
Rim material has higher hardness and higher strength than the material used for the underlying structure (i.e. web, gussets)
These features will reduce the lead time and costs. Fabricated manufacturing ensures a fast delivery.
This is especially beneficial in an emergency situation, where the existing gear rim is suffering from damage
Features
External teeth
Maximum diameter: 16000 mm
Toothed face width: 1700 mm
Maximum module: 45 by hob
Maximum module: 65 gear finishing cutter
Internal teeth
Maximum Diameter: 6500 mm
Maximum module: 25.4
Toothed face width: 400 mm
| Forging material process
Forging
Final rolling Furnace cooling
Control on production
Water quenching
Hardness testing
Rough machining
Ultrasonic testing and dimensional inspection
Final inspection certification |
Applications
Our girth gears are applied in the cement and minerals industries:
Various types of horizontal mills
Rotary dryers
Rotary kilns
Any other large gear ring application
Pinions
CITICIC Gear invested in significant resources and achieved many innovations with pinions. The right combination of material, hardness and finishing between pinion and gear is crucial for a long lifetime of the installed equipment. We design and manufacture pinions to match every customers need, no matter how unique the situation might be.
Pinion design
bored
solid on shaft / integral
self aligned
spur, helical or double helical
Materialization
forged alloyed steel
through hardened, case hardened or quenched and tempered
Spur, helical or double helical
carburized
induction
nitrided
Characteristics
gear cutting with hobs
the gear quality is checked by profile tester
tooth flank modification
profile correction
lead correction (straight/barrel)
designs /ratios according to ISO-DIN-A.G.M.A.
FEM/FEA simulation software
Standards/Certificates
UNI EN ISO
AWS
ASTM
ASME
DIN
Applications
Our pinions are applied in the cement and minerals industries:
Ball - mills
ROD - mills
Semi Autogeneous Grind (SAG)
Rotary kilns/coolers/dryers
Advantages
One Source
Original Equipment Manufacture (OEM) Technical Drawings
Gearing technical expertise for kilns and grinding mills
State of the art manufacturing facilities and quality
Global sales and service support
