ISO 14373:2024

Overview

ISO 14373:2024 - "Resistance welding - Procedure for spot welding of uncoated and coated low‑carbon steels" - is an international standard that specifies procedural and quality requirements for resistance spot welding of low‑carbon steel sheets. It applies to assemblies of two or three sheets where individual sheet thicknesses are between 0.4 mm and 3.0 mm and where the thickness ratio is ≤ 3:1. The standard covers welding using pedestal machines, portable guns, automatic and robotic equipment, multi‑spot machines and similar resistance‑welding systems.

Keywords: ISO 14373:2024, resistance spot welding, low‑carbon steels, spot welding procedure, coated steels.

Key technical topics and requirements

• Scope and materials: Applies to uncoated, metallic‑coated and weldable non‑metallic‑coated low‑carbon steels; includes guidance on surface condition and pre‑treatments.
• Surface and edge conditions: Surfaces must be free of grease, scale and excessive contamination; edge distance should be ≥ 1.25 × weld diameter (d).
• Weld pitch and spacing: Minimum weld pitch guidance (expressed relative to sheet thickness t and weld diameter d) is given to avoid current shunting and ensure consistent weld size.
• Electrodes: Electrode material must be a copper alloy with high thermal/electrical conductivity (see ISO 5182). Electrode tip sizing guidance is provided, including the formula d = a√t (where factor a is typically 5–7) for truncated‑cone electrodes.
• Weld assessment and testing: Requirements for weldability testing, production testing and testing frequency; includes weld quality criteria such as weld diameter, strength and visual acceptance (distortion, surface condition).
• Weld quality metrics: Cross‑tension strength (CTS) values included; tensile shear testing and failure descriptions specified (figures and test methods referenced).
• Informative guidance: Annex A (equipment recommendations), Annex B (typical spot‑welding conditions), Annex C (applicable steel types).

Practical applications and who uses this standard

ISO 14373:2024 is intended for:

• Welding engineers and procedure developers who specify spot‑welding parameters for production.
• Automotive and appliance manufacturers using resistance spot welding for sheet assemblies.
• Robotics integrators and automation engineers implementing automatic/robotic spot welding.
• Quality managers and inspectors assessing weld acceptance, testing frequency and weldability.
• Tooling and electrode suppliers specifying electrode materials, dimensions and maintenance intervals.

Practical value: ensures repeatable weld quality, reduces rework, informs equipment selection (portable to robotic), and supports conformity with industry best practice for coated and uncoated low‑carbon sheet assemblies.

Related standards (normative references)

• ISO 10447 (peel and chisel testing)
• ISO 15609‑5 and ISO 15614‑12 (welding procedure specification and tests)
• ISO 17677‑1 (welding vocabulary)
• Electrode and component standards: ISO 5182, ISO 1089, ISO 5184, ISO 5830, ISO 5821

For implementation, consult Annexes A–C of ISO 14373:2024 for detailed guidance on equipment, spot‑welding conditions and typical steel types.