ISO 14270:2016

Overview

ISO 14270:2016 - Resistance welding - Destructive testing of welds - Specimen dimensions and procedure for mechanized peel testing resistance spot, seam and embossed projection welds - defines specimen geometry and a mechanized peel testing procedure for assessing the peel strength of resistance spot, seam and embossed projection welds in overlapping metallic sheets. The standard applies to sheet thicknesses from 0.5 mm to 3.0 mm and to welds with a maximum diameter of 7√t (t = sheet thickness in mm). It is intended to determine the maximum peel force (MPS) a test specimen can sustain.

Key technical topics and requirements

• Scope & applicability: Single spot, seam and embossed projection welds in overlapping sheets, any metallic material, thickness 0.5–3 mm. Note: welds between 5√t and 7√t may give lower-than-expected peel strength with the recommended specimen width.
• Specimen dimensions and tolerances: Tabled specimen dimensions (e.g., flange length and specimen width typically 50 mm for 0.5 < t ≤ 3.0 mm), free length between clamps, edge distance and positional accuracy (weld position ±1 mm).
• Bending procedures: Two manufacturing sequences - bending-after-welding (recommended for thin/soft materials, multiple weld pieces) and welding-after-bending (recommended for high-strength or thicker materials). Inner bend radius r ≈ 2t is recommended; flange length accuracy after bending should be ≤ ±1.0 mm.
• Test equipment & measurement: Use a tensile testing machine conforming to ISO 7500‑1. Force-measuring accuracy shall be ≤ ±1 %. Tests at room temperature and performed at least 10 hours after welding.
• Test reporting & acceptance of results: Record individual MPS values, mean and standard deviation, failure mode (e.g., plug, interfacial), weld diameter, welding conditions, bend radius and specimen details. If fracture originates at the bent corner, re-test with larger inner radius.
• Normative references & alignment: Revised to align with ISO 17677‑1 (welding vocabulary and failure modes).

Practical applications and users

• Quality control and acceptance testing for resistance-welded assemblies in automotive, aerospace, electronics and general manufacturing.
• Welding procedure and process validation, material qualification, failure analysis and R&D where mechanized peel testing quantifies peel strength.
• Primary users: welding engineers, laboratory technicians, quality managers, materials scientists and third‑party testing laboratories performing destructive weld testing.

Related standards

• ISO 17677‑1 - Resistance welding vocabulary and failure modes (referenced and aligned)
• ISO 7500‑1 - Verification and calibration of tensile/compression testing machines (force-measuring requirements)
• ISO 14329 - (related standard for tensile shear and cross-tension testing; historical reference in introduction)

Keywords: ISO 14270, mechanized peel testing, resistance welding, spot weld testing, seam weld testing, embossed projection welds, peel strength, weld test specimen, destructive weld testing.