Overview
ISO 1127:1992 - Stainless steel tubes: Dimensions, tolerances and conventional masses per unit length defines standardized outside diameters, wall thicknesses, dimensional tolerances and conventional linear masses for stainless steel tubes. It adopts tube sizes from ISO 4200 and provides tabulated conventional masses for different stainless steel families (austenitic; ferritic and martensitic). The edition clarifies tolerance selection and gives conventional-mass adjustments based on assumed average densities.
Key topics
- Dimensions and size series: Outside diameters and thicknesses are selected from ISO 4200; for thicknesses greater than 14.2 mm ISO 4200 sizes apply.
- Tolerances: Specifies tolerances on outside diameter (including ovality) and on wall thickness (including eccentricity). Tolerances are given as selectable classes in the standard’s tables.
- Conventional masses per unit length: Tabulated masses for austenitic and for ferritic/martensitic stainless steel tubes. The standard explains conversion factors relative to ISO 4200 masses:
- Austenitic masses = ISO 4200 masses × 1.015 (assumed density 7.97 kg/dm³).
- Ferritic/martensitic masses = ISO 4200 masses × 0.985 (assumed density 7.73 kg/dm³).
- Other dimensional tolerances: References ISO 5252 for tolerances on dimensions not covered (e.g., ends, chamfers).
Practical applications
ISO 1127:1992 is used where consistent tube geometry, interchangeability and predictable mass/weight are required:
- Engineering and piping design for chemical, petrochemical and food processing plants.
- Specification and procurement of stainless steel tubing for instrumentation, heat exchangers and structural elements.
- Quality control, inspection and acceptance testing to verify outside diameter, wall thickness and straightness/ovality.
- Manufacturing planning for tube producers and fabricators to meet international dimensional classes.
Typical users: mechanical and piping engineers, procurement/specification writers, metallurgists, tube manufacturers, welding/fabrication shops and inspection authorities.
Related standards
- ISO 4200 - source table of plain-end steel tube sizes (used for diameter/thickness selection and base masses).
- ISO 5252 - tolerance systems for steel tubes (referenced for other dimensional tolerances).
ISO 1127:1992 helps ensure consistent sizing, tolerance control and reliable mass data for stainless steel tubing - essential for accurate material take-offs, fabrication fit-up and cross-border procurement. Keywords: ISO 1127:1992, stainless steel tubes, dimensions, tolerances, conventional mass per unit length, austenitic, ferritic, martensitic, ISO 4200, ISO 5252.
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