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PD ISO TR 25901 — Welding and Allied Processes Vocabulary Technical Reports
Welding and Allied Processes — Vocabulary (ISO/TR 25901-1/3/4, BSI UK implementation)
🔥 PD ISO TR 25901 is the UK implementation, published by BSI, of the ISO/TR 25901 series of technical reports, prepared by UK Technical Committee WEE/1 (Briefing committee for welding) and focused on the vocabulary of welding and allied processes. The three parts in this batch are: Part 1, general terms; Part 3, welding processes; and Part 4, arc welding. Together they form a unified, standardised multilingual terminology system for the welding field, an important foundation for welding technical exchange, standards referencing, and international cooperation.
💡 Welding is a key manufacturing process, yet different countries, industries, and vendors often use different terms for the same concept. A unified vocabulary (with English, French, German, and other multilingual indexes) eliminates ambiguity and ensures consistent understanding of welding process documents, standards, and certification results worldwide.
1. Series Overview 📌
ISO/TR 25901 is the “Welding and allied processes — Vocabulary” series of technical reports, developed by ISO/TC 44 (Welding and allied processes) to provide unified, authoritative definitions for welding terminology, with corresponding terms in English, French, German, and other languages for international exchange and standards referencing. BSI adopts them as “PD ISO/TR 25901-xxx”.
In this batch, Part 1 gives general welding terms (basic concepts, joints, grooves, symbols, etc.), Part 3 gives terms for the various welding processes (fusion, pressure, brazing, etc.), and Part 4 gives detailed terms for arc welding. Together they cover the core areas of welding vocabulary.
2. Series Structure and Part Highlights 📋
| Part | Document Title | ISO Edition | Core Content |
|---|---|---|---|
| Part 1 | General terms | ISO/TR 25901-1:2016 (Ed. 1.0) | General welding terms: basic concepts, joints, grooves, welds, and related process terms |
| Part 3 | Welding processes | ISO/TR 25901-3:2016 (Ed. 1.0) | Terms for the various welding processes: fusion, pressure, brazing, solid-state, etc. |
| Part 4 | Arc welding | ISO/TR 25901-4:2016 (Ed. 1.0) | Arc welding terms: welding current characteristics, arc welding processes, welding consumables, and welding equipment terms |
All three parts are classified under ICS 01.040.25 (Vocabulary: welding and allied processes) and ICS 25.160.10 (Welding processes), handled by the same UK technical committee WEE/1, progressing from “general” to “processes” to “arc welding”.
⚠️ This series comprises technical reports (TR) providing vocabulary definitions and multilingual correspondence. They are normative reference documents rather than mandatory certification standards. Welding process and quality requirements are set by the relevant product and process standards (e.g., ISO 9606, ISO 5817, ISO 3834).
3. Key Technical Requirements 🔧
1. General Terms (Part 1)
Part 1 specifies general terms in the welding field, mainly including:
- Basic concepts: welding, workpiece, base metal, heat-affected zone, etc.;
- Joints and grooves: joint types (butt, fillet, T, lap, etc.), groove types (V, U, J, etc.), and dimensional terms;
- Welds and processes: weld parts (weld toe, root, weld metal) and process-related terms;
- Symbols and abbreviations: unified welding symbols and common abbreviations.
2. Welding Process Terms (Part 3)
Part 3 specifies terms for the various welding processes, organised by process type:
- Fusion welding processes: arc welding, gas welding, electron-beam welding, laser welding, etc.;
- Pressure welding processes: resistance welding (spot, seam), friction welding, diffusion welding, etc.;
- Brazing and solid-state welding: brazing, soldering, diffusion brazing, etc.;
- Other related processes: cutting, thermal spraying, surfacing, and related process terms.
3. Arc Welding Terms (Part 4)
Arc welding is the most widely used welding method. Part 4 refines terminology for arc welding, mainly including:
- Welding current characteristics: current type (DC, AC), polarity, and arc characteristics;
- Arc welding processes: manual metal arc welding, gas metal arc welding (MIG/MAG), tungsten inert gas welding (TIG), submerged arc welding, flux-cored arc welding, etc.;
- Welding consumables: electrodes, wires, fluxes, shielding gases;
- Welding power sources and equipment: power-source characteristics, welding machines, and auxiliary equipment terms.
Each part also provides informative annexes (Annex A/B) with alphabetical indexes in English, French, German, and other languages for easy multilingual lookup.
🚨 Non-uniform welding terminology leads to misreading of welding procedure specifications (WPS), welder qualifications (e.g., ISO 9606), and non-destructive test reports in international projects, causing quality disputes or even accidents. Using a unified vocabulary is the basis for ensuring welding quality and international mutual recognition.
4. Engineering Practice Applications 🛠️
- 📝 Process documents: when preparing welding procedure specifications (WPS), procedure qualification records (PQR), and work instructions, use this series’ unified terms to avoid ambiguous expression.
- 🌍 International cooperation: in cross-border projects, import/export equipment, and overseas engineering, use the multilingual correspondence to eliminate language barriers and ensure consistent understanding between Chinese and foreign parties.
- 📋 Training and qualification: in welder training, examination, and qualification (e.g., ISO 9606), use unified terms as the basis for assessment and communication.
- 🔍 Quality traceability: in welding quality records, inspection, and non-destructive testing, use standard terms to standardise records, improving traceability and readability.
5. Frequently Asked Questions ❓
❓ Q: Is the ISO/TR 25901 series mandatory?
A: No. It is a technical report (TR) providing vocabulary definitions and multilingual correspondence — a normative reference document. Welding quality and process requirements are set by the relevant product and process standards.
A: No. It is a technical report (TR) providing vocabulary definitions and multilingual correspondence — a normative reference document. Welding quality and process requirements are set by the relevant product and process standards.
❓ Q: Why does welding need a dedicated vocabulary standard?
A: Welding involves many process, joint, groove, and equipment concepts, and different countries use different names. A unified vocabulary eliminates ambiguity and ensures consistent understanding of process documents, standards, and certification worldwide.
A: Welding involves many process, joint, groove, and equipment concepts, and different countries use different names. A unified vocabulary eliminates ambiguity and ensures consistent understanding of process documents, standards, and certification worldwide.
❓ Q: What is the purpose of the multilingual indexes?
A: The annexes give alphabetical indexes in English, French, German, and other languages, helping non-native readers quickly find the corresponding term, supporting international trade, cross-border projects, and standardisation work.
A: The annexes give alphabetical indexes in English, French, German, and other languages, helping non-native readers quickly find the corresponding term, supporting international trade, cross-border projects, and standardisation work.
🔍 Q: What is the difference between Parts 3 and 4?
A: Part 3 covers terms for all major welding processes (fusion, pressure, brazing, etc.); Part 4 specifically details arc welding (the most widely used fusion method), including current characteristics, processes, consumables, and equipment.
A: Part 3 covers terms for all major welding processes (fusion, pressure, brazing, etc.); Part 4 specifically details arc welding (the most widely used fusion method), including current characteristics, processes, consumables, and equipment.