Overview
EN ISO 17279-1:2018 - Welding - Micro joining of 2nd generation high temperature superconductors - Part 1: General requirements for the procedure (ISO 17279-1:2018) is a CEN-adopted ISO standard that defines the rules for specification and qualification of resistance-free micro-joining procedures for 2nd generation high temperature superconductors (2G HTS). The document establishes the requirement for a Welding Procedure Specification (WPS) and the associated qualification (WPQR) as a basis for planning, quality control and release-to-production of micro-joining operations. It applies to direct autogenous joining of the thin ReBCO superconducting layer (typically 1–2 µm) within 2G HTS tape or wire assemblies and excludes soldering, brazing, filler metals, 1G BSCCO and low-temperature superconductor (LTS) joining.
Key Topics and Requirements
- Procedure specification and qualification: Requirements for preparing a preliminary WPS (pWPS), completing a Welding Procedure Qualification Record (WPQR), and issuing a WPS for production use.
- Special process control: Treats micro-joining as a special process under quality system standards - requiring documented procedures, records, and operator/equipment qualification.
- Joint design: Defines acceptable joint types (e.g., lap and bridge joints) and design considerations compatible with 2G HTS multilayer construction.
- Micro-joining process: Focus on direct autogenous (filler-free) joining of the superconducting layer and subsequent oxygenation-annealing to recover superconducting properties and achieve near-zero electrical resistance at the joint.
- Test specimens and qualification tests: Use of standard test specimens, specific micro-joining and oxygenation-annealing steps for qualification, acceptance criteria, re-testing rules and test records.
- Equipment, traceability and final treatment: Requirements for equipment, identification, traceability and production run joint final treatment.
- Third-party check: Provisions for independent verification of procedure qualification and compliance.
Practical Applications
- Ensuring consistent, low-resistance joints in 2G HTS tapes used in power cables, fault current limiters, magnets, motors/generators and medical or scientific magnets.
- Establishing reproducible micro-joining processes for manufacturing lines and R&D labs developing HTS devices.
- Serving as a compliance and quality-control framework for suppliers, integrators and contract-welding providers working with 2G HTS materials.
Who Should Use This Standard
- Welding engineers and procedure writers preparing WPS/WPQR for 2G HTS joining
- Quality managers and auditors overseeing special-process controls
- Manufacturers and OEMs of HTS-based equipment and superconducting cable producers
- Test labs, third-party certification bodies and R&D teams developing resistance-free joining techniques
Related standards
- Prepared by ISO/TC 44 (Welding and allied processes); see other parts of the ISO 17279 series and applicable quality-system standards referenced by manufacturers and certifying bodies.
Keywords: EN ISO 17279-1:2018, 2G HTS, micro joining, high temperature superconductors, WPS, WPQR, oxygenation-annealing, resistance-free joining, procedure qualification.