Overview
EN ISO 9453:2020 - Soft solder alloys: Chemical compositions and forms specifies the chemical composition requirements and common product forms for soft solder alloys. The standard covers alloys that contain two or more of: tin, lead, antimony, copper, silver, bismuth, zinc, indium and cadmium. Published as an ISO document and adopted by CEN (EN ISO 9453:2020), this fourth edition (2020) supersedes the 2014 version and includes updates such as new alloy entries and alignment with IEC alloy naming.
Key topics and technical requirements
- Scope and definitions: Clear definition of “soft solder” (liquidus normally below 450 °C) and batch/unit concepts.
- Chemical composition: Compositions for specified alloys are provided in tabular form (see Table 2 and Table 3). Limits for major and trace elements are given; remainder (“Rem”) is calculated to 100 %.
- Forms of delivery: Typical solder product forms are listed - ingot, slab, stick, bar, rod, wire, pellets, preforms, spheres, ribbons, powder, pastes and creams. Not all alloys are available in every form.
- Unit of product and marking: The standard defines units of product by form (e.g., a single ingot, a reel of wire) and requires batch marking, labelling and packaging details; includes health-and-safety and lead-free / lead-containing markings as applicable.
- Sampling and analysis: Inductively coupled plasma (ICP) is the recommended method for chemical analysis. Spark-OES and AAS are acceptable alternatives if agreed between supplier and purchaser.
- Information notes: Melting/solidus temperatures in the tables are informational only and not prescriptive requirements. Patent and licensing notices are highlighted where applicable.
Applications and practical value
- Ensures consistent solder alloy chemistry for reliable wetting, melting behavior and joint performance in industries such as electronics assembly, electrical connections, plumbing and general metal joining.
- Helps manufacturers and suppliers standardize product specification, labelling and quality control.
- Supports procurement, quality assurance and test laboratories in verifying alloy identity and compliance using ICP or agreed test methods.
- Guides decisions about product form (wire, paste, preform) and traceability requirements for production batches.
Who should use this standard
- Solder manufacturers and alloy producers
- Electronic assemblers, repair shops and OEMs
- Quality managers, metallurgists and testing laboratories
- Procurement specialists and standards/technical committees
Related standards
- IEC 61190-1-3 (alloy short names and chemical composition) - EN ISO 9453:2020 includes an Annex comparing alloy numbers with IEC nomenclature.
Keywords: EN ISO 9453:2020, soft solder alloys, chemical composition, solder forms, ICP analysis, solder marking, solder standards.