Thermal spraying - Thermally sprayed coatings - Symbolic representation on drawings (ISO 12671:2021); German version EN ISO 12671:2021
1Key Takeaways
This document specifies how the symbolic representation of a thermally sprayed layer is used in drawings.
2Expert Interpretation
An in-depth analysis of DIN EN ISO 12671:2021, the international standard for symbol representation of thermal spray coating drawings, covering the symbol system composition, marking position rules, multi-layer coating representation methods and typical application cases. It is suitable for the standardization needs of engineering drawings in mechanical manufacturing, aerospace and other fields.
Standard Framework and Technology Evolution
DIN EN ISO 12671:2021, the core standard for thermal spray coatings, replaces the 2014 edition and features three major improvements: updated terminology (synchronized with the latest standards such as ISO 14917), material specification references (integrating the ISO 14232-1:2017 powder standard), and improved example illustrations. This standard was jointly developed by ISO/TC 107 and CEN/TC 240, and led by the German National Association for Standardization (NAS).
Symbol system composition
| Element type | Symbol example | Function description |
|---|---|---|
| Basic symbol | TS | Identifies thermal spraying process |
| Additional symbols | TC/BC | Distinguish functional layer (TC=surface layer, BC=bonding layer) |
| Process symbol | APS/PFS | Marks specific spraying method (atmospheric plasma/powder flame) |
Drawing marking specifications
Example 1: Composite coating marking
ISO 12671-TS-TC-APS-ISO 14232-1:2017-Al2O3/TiO2 60/40-250-as
Indicates: Atmospheric plasma spraying (APS) process is used, the material is a mixed powder of 60% Al2O3 and 40% TiO2 according to the ISO 14232-1 standard, the surface layer thickness is 250μm, and it is kept in the sprayed state (as)
Example 2: Post-processing requirements
ISO 12671-TS-TC-PFS-ISO 14232-1:2017-NiCrBSi-350-f+m/c
Means: Powder flame sprayed nickel-based alloy, requiring remelting treatment (f) and then machining (m/c) to 350μm
Implementation points
- Marking position: The symbol system must include three parts: leader, baseline and external marking. The end of the baseline can use a bifurcated structure to distinguish multiple layers
- Patented process: When patented spraying technology is involved, the manufacturer code must be indicated in the marking or associated through the parts list
- Non-spraying area: Use wide dashed lines to mark the allowed spraying area. The unmarked area is the default prohibited spraying area
Technical comparison
| Version features | 2014 version | 2021 version |
|---|---|---|
| Material Standard References | ISO 14232-1:2001 | ISO 14232-1:2017 |
| Terminology | Independent Definition | Synchronized with ISO 14917:2019 |
| Graphical Examples | Basic Examples | Add Patent Process Annotation Examples |