ISO 17634:2015

Overview - ISO 17634:2015 (Welding consumables classification)

ISO 17634:2015 specifies the classification of tubular cored electrodes used for gas shielded metal arc welding (GMAW) of creep‑resisting and low‑alloy elevated‑temperature steels, in the post‑weld heat‑treated condition. The standard defines how to describe and classify electrodes by the chemical composition and/or the mechanical (tensile) properties of the all‑weld metal, plus additional attributes such as shielding gas, welding position and hydrogen content.

Keywords: ISO 17634, tubular cored electrodes, gas shielded metal arc welding, creep‑resisting steels, classification, welding consumables, all‑weld metal.

Key topics and technical requirements

• Two classification systems
  • System A - classification based primarily on chemical composition of all‑weld metal (with associated mechanical requirements).
  • System B - classification based on tensile strength and chemical composition of all‑weld metal (specific strength codes such as 49, 55, 62, 69 denote tensile ranges).
• Symbolic designation: A structured symbol (starting with “T”) conveys product type, composition/strength, electrode core/usability, shielding gas, welding position and optionally hydrogen class.
• All‑weld metal testing: Mechanical tests (tensile, impact) and chemical analysis are specified for classification; test methods reference ISO 15792 series.
• Shielding gas and positional qualification: One electrode can be classified using different shielding gases; welding positions conform to ISO 6947 and positional fillet tests per ISO 15792‑3.
• Hydrogen control: Hydrogen content of deposited metal is specified and tested (ISO 3690 referenced).
• Practical testing notes: Classification tests are performed on a standard electrode diameter (1.2 mm or next larger) and pulsed current is not used to determine the classification. The standard cautions that production joint properties can differ from classification test results due to welding parameters and parent‑metal variation.

Practical applications - who uses ISO 17634

• Welding engineers and metallurgists selecting filler materials for high‑temperature, creep‑resistant steel components (boilers, power‑plant piping, pressure vessels, turbines).
• Consumable manufacturers who need a recognized classification and designation for tubular cored electrodes.
• Quality managers and procurement specifying consumables and ensuring traceability and conformity to classification on labels and data sheets.
• Fabricators and inspectors validating that electrode choice meets strength, chemistry and hydrogen requirements for post‑weld heat‑treated joints.

Related standards and references

Normative references used by ISO 17634 include: ISO 544, ISO 3690, ISO 6947, ISO 14175, ISO 14344, ISO 15792‑1/‑3, and ISO 80000‑1 - these define test methods, gas mixtures, welding positions, hydrogen measurement and delivery/marking conventions.

Use ISO 17634 classification to ensure consistent selection, procurement and documentation of tubular cored electrodes for elevated‑temperature, creep‑resisting steel welds.