Overview
ISO 1005-8:1986 - "Railway rolling stock material - Part 8: Solid wheels for tractive and trailing stock - Dimensional and balancing requirements" defines dimensional, surface-finish and balancing requirements for forged, rolled or cast solid wheels used on railway tractive and trailing stock. The standard sets machining allowances, tolerance classes, surface roughness parameters and residual static unbalance limits, and it requires coordination with the general technical delivery rules of ISO 404 and related quality parts of ISO 1005.
Key topics and technical requirements
- Scope and wheel types: Applies to solid wheels with curved or straight webs in various degrees of finish (unmachined, rough machined, half finished, finished, ready for assembly).
- Dimensional requirements: Detailed tolerances for unmachined, finished and ready-for-assembly conditions; machining allowances; geometric tolerances (form, orientation, location, run-out). Two tolerance categories are provided (Y and Z), with Y subdivided by speed (YN normal, YH high speed).
- Surface roughness: Surface quality specified using the arithmetic mean deviation (Ra) of the profile (see ISO 468). Typical Ra requirements for bores in ready-for-assembly wheels are given and vary by tolerance category.
- Balancing / residual unbalance: Static unbalance limits are specified and related to operating speed; final unbalance verification is carried out in accordance with ISO 1005/6. Purchaser and manufacturer must agree any specific maximum unbalance values and the applicable speed range.
- Inspection and verification: The standard identifies mandatory and optional verifications for specific dimensional characteristics and describes inspection conditions and sample/verification agreements to be made at enquiry/order time. Definitions and symbols follow ISO 1101 for geometrical tolerancing.
- Purchaser’s responsibilities: Purchaser must supply drawing, chosen tolerance/testing category (Y or Z; A or B), degree of finish and any deviations or special checks required.
Practical applications
ISO 1005-8 is used by:
- Wheel manufacturers (forging, rolling, casting) to set production tolerances and machining allowances.
- Wheelset assemblers and axle manufacturers to ensure proper fit and run-out when mounting wheels.
- Railway procurement and specifications engineers for supply contracts and acceptance criteria.
- Maintenance, quality control and test laboratories for inspection, surface-roughness measurement and static unbalance testing.
Related standards
- ISO 404 - General technical delivery requirements for steel products
- ISO 1005 (other parts, e.g., Part 6) - Quality requirements for solid wheels
- ISO 468 - Surface roughness parameters (Ra)
- ISO 1101 - Geometrical tolerancing and symbols
Keywords: ISO 1005-8, railway rolling stock, solid wheels, dimensional requirements, surface roughness, residual unbalance, wheel tolerances, balancing, wheel manufacturing, ISO standards.
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