Overview
CEN ISO/TR 17844:2004 "Welding - Comparison of standardised methods for the avoidance of cold cracks" provides comprehensive guidance for the avoidance of hydrogen-induced cold cracking in arc welding of ferritic steels. This standard builds on ISO/TR 17671-2, presenting an in-depth comparison of widely-recognized methods used across the welding industry. It is essential for fabricators, welding engineers, and quality professionals seeking to mitigate the risk of cold cracking during manual, semi-mechanized, mechanized, and automatic arc welding processes.
The technical report, developed by CEN Technical Committee 121 in cooperation with ISO/TC 44, details methods applicable to a variety of ferritic steels, excluding ferritic stainless steels, in all product forms. It consolidates best practices, test methods, and criteria for selecting and applying preventive measures during welding operations to ensure product integrity and service reliability.
Key Topics
- Methods Compared: The document compares four major standardized approaches for cold crack avoidance:
- Critical Input Parameters: Each method considers key factors such as:
- Steel composition (carbon equivalent/CET/Pcm)
- Welding heat input
- Joint geometry and material thickness
- Weld metal hydrogen level
- Required preheat temperature
- Test Data and Procedures: Guidance is provided on:
- Selecting proper cracking test methods (e.g., CTS, y-groove, Tekken tests)
- Application ranges for different parent metals, thicknesses, and welding processes
- Step-by-step determination of preheat requirements
- Special considerations for complex welds and higher-risk scenarios
Applications
CEN ISO/TR 17844:2004 is designed for use in various industrial sectors where ferritic steels are welded, including:
- Structural Engineering: Ensures weld integrity in structural steelwork, bridges, and buildings by mitigating hydrogen cracking risks.
- Heavy Machinery & Equipment: Supports fabrication of components subjected to dynamic loads or thick-section welding.
- Pressure Vessels & Pipelines: Enables safe production of vessels and pipes where the integrity of welded joints is critical for safety.
- Automated and Manual Welding: Applicable across manual, semi-automatic, and fully automated welding operations, with tailored recommendations for each.
Practical benefits include increased safety, reduced risk of in-service failure, and improved compliance with European and international welding standards.
Related Standards
For comprehensive welding quality control and cold crack prevention, it is recommended to refer to the following related standards:
- EN 1011-2 / ISO/TR 17671-2 - Welding recommendations for arc welding of ferritic steels
- ISO 3690 - Measurement of hydrogen in deposited metal
- CR ISO 15608 - Guidelines for grouping of steel materials for welding
- ISO 4063 - Numbering system for welding processes
By following CEN ISO/TR 17844:2004 alongside these references, organizations can establish robust welding procedures, select appropriate materials and consumables, and apply effective preheating and hydrogen control strategies to minimize the risk of cold cracking in welded ferritic steels.
Keywords: cold cracks, hydrogen-induced cracking, ferritic steels, arc welding, welding procedures, carbon equivalent, CET method, Pcm method, preheat temperature, welding standards, CEN ISO/TR 17844.