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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
Forging material process
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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.