How to Select Welding Rotator Capacity for a Pressure Vessel
Direct answer
Select a welding rotator from the maximum complete rotating weight—not the empty shell weight—and verify how that weight is shared by the drive and idler supports. Diameter, support spacing, centre-of-gravity offset, attachments, wheel loading, required traction and duty cycle can make a nominal tonnage unsuitable. For WUXI ABK HGK and HGZ models, the published rating refers to one standard set comprising one drive unit and one idler unit under an evenly distributed concentric load. The final allowable configuration must be stated in the signed technical specification.
1. Calculate the complete rotating weight
Include shell courses and heads; flanges, nozzles and manways; installed internals; temporary strongbacks, fixtures and clamps; rings, platforms and attachments; and any product, liquid or test medium present during rotation. Record both the normal production weight and the maximum credible rotating weight.
2. Define what the capacity rating means
A quotation should state whether the capacity applies to a complete set or an individual support unit, the number of drive and idler units included, the assumed load distribution, whether the workpiece is concentric or eccentric, and the difference between support capacity and available driving traction.
WUXI ABK rating convention
For public HGK and HGZ model tables, rated capacity means the complete standard set: one drive unit plus one idler unit, supporting an evenly distributed concentric workpiece. It must not be interpreted as the rating of each individual unit. Individual support load, tractive capacity, eccentric loading, additional idlers and engineering safety margin remain order-specific.
3. Check load distribution at each support
Heads, thick flanges, nozzles and temporary fixtures can move the centre of gravity toward one support. Provide total length and mass, centre-of-gravity position, proposed drive and idler locations, support-point spacing, and heavy attachments. Engineering should calculate the reaction load at every support point rather than assume an equal split.
4. Check diameter and roller geometry
Confirm the minimum and maximum operating diameters. Roller spacing, included angle, centreline height and wheel contact all change with diameter. The selected model must keep the workpiece stable across the required range without exceeding wheel or frame loading.
HGZ Self-Aligning Welding Rotator (Standard Series): the roller arrangement accommodates an approved diameter range without manually resetting roller spacing for each diameter.
HGK Adjustable Welding Rotator: roller spacing is set for the required diameter; the exact adjustment method follows the quotation.
5. Account for eccentricity and unstable workpieces
Tell the supplier about an eccentric centre of gravity, incomplete shells, one-sided nozzles or platforms, temporary fit-up loads, expected out-of-roundness and axial-drift risk. A catalogue capacity alone cannot establish safe suitability when these conditions are unknown.
6. Separate support capacity from drive traction
The frame and rollers may support a load that the drive system cannot rotate reliably. The proposal should separately address driving torque and traction, wheel material and friction, workpiece surface condition, incline or axial force, acceleration and stopping, duty cycle, required surface speed and speed stability.
7. Select with an engineering margin
There is no universal percentage margin. The required margin depends on uncertainty in weight, eccentricity, shock, support arrangement, future workpieces and duty cycle. If the workpiece is near a standard model limit, request an engineering review and document the approved operating condition.
8. Verify the selection during FAT
Agree the test load or simulation method before manufacture is completed. Check machine identity, approved drawings, drive and idler quantity, support arrangement, rotation in both directions, speed range under the agreed condition, stopping and emergency stop, adjustment or self-aligning movement, wheel contact, frame behaviour, control functions, deviations and signed acceptance.
WUXI ABK reference models
HGK-10 Adjustable: 10 t; 100–1,000 mm/min; 400–4,000 mm.
HGK-50 Adjustable: 50 t; 100–1,000 mm/min; 400–6,000 mm.
HGK-200 Adjustable: 200 t; 100–1,000 mm/min; 800–8,000 mm.
HGZ-10 Self-aligning, Standard Series: 10 t; 100–1,000 mm/min; 400–3,500 mm.
HGZ-50 Self-aligning, Standard Series: 50 t; 100–1,000 mm/min; 800–5,000 mm.
HGZ-100 Self-aligning, Standard Series: 100 t; 100–1,000 mm/min; 1,000–6,000 mm.
Each published capacity above refers to one drive unit plus one idler unit under an evenly distributed concentric load. Final support arrangement, individual-unit loading, traction, eccentricity and safety margin are governed by the signed technical agreement.
Information to send for an engineering review
1. Maximum and normal rotating weight.
2. Dimensional drawing and centre-of-gravity position.
3. Minimum and maximum diameter.
4. Overall length and proposed support spacing.
5. Attachments, eccentric loads and fit-up condition.
6. Welding process and required surface speed.
7. Duty cycle and production target.
8. Wheel-material preference and workpiece surface condition.
9. Power supply, control and integration requirements.
10. Inspection, FAT, documentation, installation and warranty requirements.
Send the workpiece drawing and the ten RFQ inputs to jan@weldc.com for a project-specific rotator selection review.
Disclosure and review
This technical guide is published by Wuxi ABK Machinery Co., Ltd., a welding-rotator manufacturer. It explains the company’s public rating convention and general procurement checks; it is not a substitute for the approved project calculation, operating manual or signed technical agreement.
Address: 20#, Yangnan Road, Yangshi, Luoshe Town, Wuxi, Jiangsu, China.
Last factual review: 24 July 2026. Reviewed by: WUXI ABK Technical Team.
