Overview
EN ISO 2702:2022 - Fasteners: Heat treated tapping screws - Mechanical and physical properties defines the required mechanical and physical characteristics and the associated test methods for heat‑treated steel tapping screws with thread sizes ST2,2 to ST9,5 (ISO 1478). Applicable when tested at ambient temperatures of 10 °C to 35 °C, the standard covers tapping screws designed to form mating threads in sheet metal (without deforming their own threads) and that are not intended to be pretensioned.
Key facts:
- Published December 2022 and adopted by CEN as EN ISO 2702:2022.
- Supersedes the 2011 edition; includes updated requirements and new test/inspection clauses.
- Materials: cold‑heading steels suitable for case‑hardening (see referenced standards such as ISO 4954).
Key Topics and Requirements
- Mechanical and physical properties: Specified properties include surface hardness, case‑hardened depth (CHD), core hardness, microstructure, thread‑forming ability, torsional strength and ductility.
- Surface hardness: Minimum specified surface hardness after heat treatment is 450 HV 0,3. A purchaser may request a maximum surface hardness to reduce environmental hydrogen embrittlement risk.
- Case‑hardened depth (CHD): Values and limits for CHD are given by thread size in the standard (see Clause 5.3 and Table 2).
- Core hardness and microstructure: Core hardness limits and microstructure requirements with Vickers testing and metallographic checks (referenced ISO 6507‑1).
- Test methods (Clause 6): Includes surface hardness test, CHD determination, core hardness test, microstructure examination, drive/ thread‑forming test, torsional strength test and ductility test.
- Inspection and conformity: New Clause 7 defines manufacturer, supplier and purchaser inspection responsibilities; Clause 8 prescribes marking and labelling requirements.
Practical Applications
- Ensures consistent quality and performance of heat‑treated tapping screws used in sheet‑metal assemblies across automotive, appliance, construction, electronics and general manufacturing.
- Helps fastener manufacturers implement standard production controls and test regimes.
- Used by purchasing/specification engineers to define acceptance criteria for supplied fasteners.
- Useful for independent testing laboratories and quality assurance teams performing conformity testing.
Who Should Use It
- Fastener manufacturers and heat‑treaters
- OEMs and component manufacturers specifying tapping screws
- Quality/control engineers and inspection labs
- Procurement teams writing technical specifications
Related Standards
- ISO 1478 (Tapping screws thread)
- ISO 6507‑1 (Vickers hardness test)
- ISO 1891‑4 (Fasteners - Vocabulary: inspection and acceptance)
- ISO 16228 (Types of inspection documents)
- Referenced material standards (e.g., ISO 4954) for cold‑heading steels
This standard is essential for stakeholders seeking reliable, standardized requirements and test methods for heat‑treated tapping screws in sheet‑metal applications.
