Overview
EN ISO 14920:2023 - Thermal spraying: Spraying and fusing of self-fluxing alloys specifies procedures for thermal spraying of self‑fluxing alloys that are simultaneously or subsequently fused to produce a homogeneous, diffusion‑bonded coating. The standard is the 2023 ISO/CEN edition that supersedes EN ISO 14920:2015 and clarifies materials usable for fusing, grit‑blasting media, and spray method influences on coating quality.
Key topics and technical requirements
- Scope and purpose: Defines requirements for producing fused, diffusion‑bonded coatings using self‑fluxing alloy powders and thermal spray processes.
- Substrate influence and design: Addresses heat transfer during fusion and potential substrate effects such as scaling, stress relief needs, and irreversible metallurgical changes. Highlights susceptibility of martensitic steels to stress cracking.
- Material limitations:
- Austenitic steels (including stainless and chromium‑nickel steels) can be fused without structural transformation.
- Other base metals must have melting points well over 1 200 °C.
- Empirical upper limits for alloying elements in ferritic steels are given (C = 0.5 %; Cr = 5 %; Ni = 4 %; W = 3 %; Mo = 3 %) to avoid heat‑treatment related problems.
- Spray materials and powder characteristics: Guidance on selection, composition, particle size and particle size range for powders used in simultaneous or subsequent fusion.
- Surface preparation: Requirements for pre‑treatment, grit blasting (media defined), masking, cleanliness and inspection prior to spraying.
- Spraying and fusing process: Detailed procedural elements - preheating, spraying technique, simultaneous vs subsequent fusing, fusing the deposit, cooling, and control of coating thickness.
- Post‑processing and testing: Final machining recommendations and hardness testing procedures (including reference hardness values in informative annex).
- Normative references: Includes EN 13507 (pre‑treatment of surfaces for thermal spraying).
Practical applications
- Use this standard when specifying or performing thermal spray deposition of self‑fluxing alloys for wear, corrosion or restoration coatings.
- Typical applications include repair and surface protection of components in power generation, petrochemical, valves, tooling, and general industrial machinery where a diffusion‑bonded coating is required.
- The standard helps ensure repeatable coating quality, substrate safety during fusion, and consistent testing/acceptance criteria.
Who should use it
- Coating engineers, metallurgists, thermal spray operators, quality managers, procurement/specification writers, and design engineers involved in surface treatment and thermally sprayed coatings.
Related standards
- EN 13507 - Thermal spraying: Pre‑treatment of surfaces of metallic parts and components for thermal spraying.
- EN ISO 14920:2015 - superseded by the 2023 edition.
Keywords: EN ISO 14920:2023, thermal spraying, self‑fluxing alloys, spraying and fusing, diffusion‑bonded coating, surface treatment, thermally sprayed coatings.