The trunnion wheel body is the rotating support wheel that carries the weight of a trommel screen or waste sorting drum and keeps it tracking true on the support rollers. Eccentricity or an out-of-round tread makes the drum hunt, overloads the drive and wears out support rollers and tyres prematurely. Ningbo Ruican casts the wheel body near net shape and machines the bore, hub faces and tread diameter in one datum scheme, then balances it, so the drum runs smoothly at low speed under full load.
Specifications
| Parameter | Specification |
|---|---|
| Casting process | Silica sol lost wax investment casting; water glass process for wheel bodies above 40 kg |
| Material options | EN-GJS-500-7 / 65-45-12 ductile iron; EN-GJS-700-2; AISI 1045; AISI 4140 / 42CrMo4; AISI 4340 for heavy duty |
| Dimensional tolerance (ISO 8062-3 CT grade) | CT7 as-cast standard; CT6 on bore and tread after tooling review |
| Machining | CNC turning of bore, hub faces and tread diameter; 4-axis milling of bolt circle and keyway; bore to H7 |
| Surface finish (Ra) | Ra 3.2 on machined tread and bore; Ra 1.6 on bearing and seal seats; Ra 6.3 as-cast |
| Hardness / heat treatment | 170-250 HBW for ductile iron; tread induction hardened to 45-55 HRC on request; 28-34 HRC for AISI 4140 quench and tempered |
| Weight range | 6 kg to 95 kg per trunnion wheel body |
| Typical lead time | Tooling 5-7 weeks; first article samples 2-3 weeks after tooling approval; production 6-8 weeks |
Key features
- Bore, hub faces, tread and bolt circle machined in a single fixture setup, holding tread runout inside 0.15 mm so the drum tracks without hunting.
- Tread diameter turned concentric to the bore, spreading contact load evenly across the support rollers and extending tyre and roller life.
- Optional induction hardening of the tread to 45-55 HRC over a controlled case depth, giving a wear-resistant surface over a tough, shock-absorbing core.
- Spoke and rim geometry optimised during tooling design to reduce rotating mass while keeping stiffness under full drum load.
- Dynamic balancing to ISO 1940 G6.3 or better on request, with a balance report issued for every production wheel.
- Bolt circle and keyway machined to the shaft datum, so the wheel can be removed and refitted during tyre changes without re-machining.
Applications
- Trommel screens separating compost, soil, sand and aggregate fractions.
- Waste sorting drums in municipal solid waste and material recovery facilities.
- Rotary screening drums in biomass, wood chip and refuse derived fuel plants.
- Rotary drum scrubbers and washing drums in mineral processing circuits.
- Recycling plant drums processing construction and demolition waste.
- Mobile trommel units and portable screening plants used on contract sites.
Images
Quality & compliance
Every trommel screen trunnion wheel body is manufactured under the Ningbo Ruican IATF 16949 certified quality system, with documented melt chemistry, controlled pouring, and full traceability from charge to finished wheel. Material certification to EN 10204 3.1 or ASTM equivalents ships with each order, together with heat treatment charts showing the actual furnace trace and, where applied, induction hardening parameters. Hardness mapping is performed across the tread, rim and hub to confirm the hardening pattern and case depth, with tensile and impact testing on coupons or test bars from the same heat. CMM and dial indicator reports verify bore size, tread diameter, runout and bolt circle position against the approved drawing, and dynamic balancing certificates to ISO 1940 are issued where specified. FAI reports and PPAP Level 1 to Level 5 packages are prepared on request, with ultrasonic testing to ASTM A609 and magnetic particle inspection to ASTM E709 available on load path areas.
FAQ
Q1. Can you cast a trunnion wheel body to our existing drum design?
Yes. Send the drum drawing, the wheel drawing or a worn sample and we will machine bore, tread and bolt circle to match, including any keyway and set screw pattern. We routinely support retrofit and spare part programs for trommels already working in the field.
Q2. Do you recommend induction hardening the tread?
For drums running continuously on steel support rollers, induction hardening to 45-55 HRC over a controlled case depth greatly extends tread life. Where the drum runs on rubber tyres or polyurethane rollers, an unhardened ductile iron tread is usually better.
Q3. How much runout can you hold on the tread?
Machined in one setup together with the bore, we routinely hold tread runout inside 0.15 mm total indicator reading and report the measured value on the first article report. Tighter bands are achievable after a tooling and fixture review, and we can also control tread taper.
Q4. Do you balance the finished wheels?
We offer dynamic balancing to ISO 1940 G6.3 or better, with an individual balance certificate issued for every wheel we ship. Balancing is recommended for drums above roughly 1.5 m diameter, or wherever the drive and support rollers are sensitive to cyclic load.
Q5. Can you supply a replaceable tyre as well as the wheel body?
Yes. We can cast and machine the wheel body plus a separate replaceable tyre, using either a shrink or a bolted interface, so your maintenance team can renew the wearing surface on site without scrapping the whole wheel or removing the drum.
Q6. What is the typical spare parts lead time?
Once tooling exists, repeat orders ship in six to eight weeks. For urgent breakdowns we can hold agreed safety stock against a rolling forecast, and we are able to prioritise a single replacement wheel through the shop when a drum is down.
CTA
Send your trommel screen trunnion wheel body drawings, drum dimensions or a sample wheel and Ningbo Ruican will return a casting, machining and balancing proposal, usually within three working days. Contact Wendy She at sales@cnsandcasting.com or on WhatsApp +86-13777124360, or visit cnsandcasting.com to start your program.
