ISO 14373:2024
Resistance welding — Procedure for spot welding of uncoated and coated low-carbon steels

Standard No.

ISO 14373:2024

Release Date

2024

Published By

International Organization for Standardization (ISO)  IX  /  ISO

Latest

ISO 14373:2024

Introduction

Technical Overview of ISO 14373:2024

The third edition of ISO 14373 (2024) establishes updated procedures for resistance spot welding of low-carbon steels with thicknesses ranging from 0.4 mm to 3.0 mm. This international standard applies to both uncoated and coated steel assemblies, including metallic-coated and weldable non-metallic-coated varieties.

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Key Revisions in 2024 Edition

Change Category	2015 Edition	2024 Edition
Failure Type Diagrams	Included	Removed
Coating Types	Basic categories	Expanded with new variants
Strength Values	TSS only	Added CTS requirements
Distortion Tolerance	Previous limits	Reduced by 15%

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Material Specifications

The standard covers various steel forms and coatings:

• Flat-rolled steel in coil or cut lengths
• Hot-dip zinc coatings (20μm max)
• Electrolytic zinc coatings (7μm/side)
• Aluminum-silicon coatings (150g/m² max)

Surface preparation requirements mandate removal of grease, scale, and oxides through sandblasting or equivalent processes prior to welding.

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Electrode Requirements

Critical parameters for welding electrodes:

Parameter	Specification
Material	Copper alloy per ISO 5182
Tip Diameter	de = 5-7×√t (t=sheet thickness)
Cooling	≥4 L/min flow rate
Dressing	Required when tip diameter increases by 20%

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Weld Quality Standards

Minimum acceptance criteria for production welds:

Dimensional Requirements

• Weld diameter ≥ 3.5√t (t=thinner sheet thickness)
• Edge distance ≥ 1.25×weld diameter
• Weld pitch > 16t and 3×weld diameter

Strength Values

For mild steel (300MPa tensile strength):

Thickness (mm)	Tensile Shear (kN)	Cross Tension (kN)
1.0	3.2-5.1	2.5-4.2
2.0	7.2-13.5	7-11.9
3.0	12.0-22.0	12.6-21.8

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Implementation Recommendations

1. Conduct weldability testing using ISO 18278-1/2 methods before production
2. Establish quality control checks at shift changes and after electrode changes
3. For coated steels, increase electrode force by 30-50% compared to uncoated steels
4. Implement automatic electrode dressing systems for high-volume production

The standard provides detailed welding parameters in Annex B for various material combinations, including force, time, and current settings based on sheet thickness and coating type.

ISO 14373:2024 Referenced Document

• ISO 10447 Resistance welding — Testing of welds — Peel and chisel testing of resistance spot and projection welds
• ISO 15609-5 Specification and qualification of welding procedures for metallic materials - Welding procedure specification - Part 5: Resistance welding
• ISO 17677-1 Resistance welding - Vocabulary - Part 1: Spot, projection and seam welding

ISO 14373:2024 history

• 2024 ISO 14373:2024 Resistance welding — Procedure for spot welding of uncoated and coated low-carbon steels
• 2023 ISO 14373:2023 Resistance welding
• 2015 ISO 14373:2015 Resistance welding - Procedure for spot welding of uncoated and coated low carbon steels
• 2006 ISO 14373:2006 Resistance welding - Procedure for spot welding of uncoated and coated low carbon steels

Standard and Specification