Forged Raymond Mill Ring

CITIC IC forged alloyed steel Raymond mill ring

CITIC IC  is professional manufacturer and supplier of Forged Rings.Quality guaranteed,on-time delivery, after-sales warranty,We hold large inventories of alloy products in a large of variety of grade,including stainless,duplex,nickel alloy and more,The ISO 9001 management system ensure the high quality of the products.

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

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

The technical requirements of a large CITIC IC Gear ring:
1) is pretreated before normalizing surface hardening treatment, the hardness should HB210 ~ 250; mechanical performance are the ultimate strength Rb 690MPa, yield stress Rs 490MPa, elongation D5 11%, reduction of area W 25% , impact toughness Ak 30J; teeth induction hardened, hardness HRC50 ~ 55; effective hardened layer depth 3 ~ 5mm.
2) overall ultrasonic flaw detection, internal quality should meet two requirements GB7233-87 standard requirements; tooth and fillet magnetic particle inspection, quality should meet two requirements GB/T9444-88 standards.
3) Note the casting is not rounded R5 ~ R10.
4) Tooth chamfer at both ends and 1 45b.5) by two and a half ring gear tooth width of each ring coupling along the edge of a whole ring made with high strength bolts, combined with the tooth surface must be at the bottom center.
2 large ring gear manufacturing process
2.1 of rough
Steel casting blank is provided by CITIC Heavy Machinery Co., Ltd. Heavy Forging plant, run by GB11352-89 standard specifies requirements for modeling according to the casting process, smelting, casting, hit boxes, cleaning, dressing castings;. During inspection and acceptance by the drawings and Technical requirements for steel blank
Checks, according JB/T6402-92 standards issued after acceptance
Down procedure.
2.2 roughing
Crossed by drawing and stay out allowance, alignment, connection, processing both inside and outside the circle, combining face milling, drilling and other processes.
2.3 Exploration injury
Overall ultrasonic flaw detection, internal quality should meet the two requirements of GB7233-87 standards.
2.4 normalizing pretreatment
Semi-ring pairs normalizing and tempering treatment, provide a good organization for subsequent surface hardening; press drawings deformation of the half ring gear inspection after heat treatment.
2.5 Machining
First two and a half ring is made with high strength bolts connecting the ring as a whole, the overall process by drawing a circle Quannei Wai teeth and upper and lower end, and then drawing and machining milling process requirements.
2.6 Elimination of processing stress
The overall ring annealed to eliminate stress.
2.7 overall ring surface hardening
IF along the alveolar tooth surface induction hardening, hardness HRC50 ~ 55, effective hardened layer depth 3 ~ 5mm.
2.8 Final inspection
First, the detection frequency quenching, the hardness after tempering ring gear cogging meets the requirements of the drawings; secondly, to detect whether the maximum outer diameter larger size D6944 as the deformation 3mm, the mechanical correction required until qualified; Thirdly, tooth and fillet magnetic particle inspection, quality should meet two requirements GB/T9444-88 standard requirements; Finally, according to the drawings and technical requirements for final inspection.