ISO 3690-2018 PDF

Full title and description

Welding and allied processes — Determination of hydrogen content in arc weld metal. This International Standard specifies sampling and analytical procedures for the determination of diffusible hydrogen in martensitic, bainitic and ferritic steel weld metal produced by arc welding processes with filler material, including methods based on mercury displacement and headspace collection with an inert gas (for example argon).

Abstract

The standard defines procedures to collect and measure diffusible hydrogen from welded specimens while controlling collection temperature to avoid thermal activation of non-diffusible hydrogen. Measurement techniques covered include displaced-volume determination (mercury displacement) and instrumental measurement of gas in a headspace (for example thermal conductivity detectors). Annexes provide recommendations and restrictions for comparison with older glycerine-based methods.

General information

• Status: Published (International Standard).
• Publication date: 2018 (ISO edition published July 2018; adopted as EN ISO 3690:2018 in September 2018).
• Publisher: International Organization for Standardization (ISO). Drafting/technical work prepared by IIW (International Institute of Welding).
• ICS / categories: 25.160.40 (Welded joints and welds).
• Edition / version: Edition 4 (2018).
• Number of pages: 23 pages (ISO published version).

Scope

This standard applies to sampling, specimen preparation (weld specimen production) and analytical determination of diffusible hydrogen in arc weld metal of martensitic, bainitic and ferritic steels when welded using arc processes with filler material. It specifies collection methods (mercury displacement or inert‑gas headspace) and the required temperature control during collection to avoid measuring non-diffusible hydrogen. It does not replace specific contract or product acceptance criteria but provides standardized test methods for comparability of hydrogen measurements.

Key topics and requirements

• Sampling and specimen production procedures for weld deposits (manual metal‑arc, submerged arc, tubular cored and gas‑shielded wires where applicable).
• Collection of diffusible hydrogen by mercury displacement (displaced volume measurement).
• Collection of diffusible hydrogen into a headspace (inert gas) and instrumental measurement (e.g., thermal conductivity detector).
• Controlled collection temperature to prevent activation of non‑diffusible hydrogen.
• Calibration, linearity checks, calculation and expression of results, plus data recording and reporting requirements.
• Informative annexes with recommendations and restrictions regarding older glycerine‑based methods and notes on accuracy/reproducibility.

Typical use and users

Used by welding laboratories, metallurgical testing facilities, welding engineers, qualification bodies, welding consumable manufacturers and quality assurance personnel to quantify diffusible hydrogen in weld metal as part of procedure qualification, consumable evaluation and failure analysis where hydrogen‑induced cracking risk must be managed.

Related standards

Replaces ISO 3690:2012. Related documents commonly used together include welding recommendations and procedure standards (for example ISO/TR 17671‑1) and standards for welding consumables and gases. National/adopted versions exist (EN ISO 3690:2018 and corresponding national publications).

Keywords

hydrogen, diffusible hydrogen, weld metal, arc welding, mercury displacement, headspace collection, thermal conductivity detector, weld testing, IIW, weld qualification.

FAQ

Q: What is this standard?

A: ISO 3690:2018 is an International Standard that specifies sampling and analytical procedures to determine diffusible hydrogen content in arc weld metal of martensitic, bainitic and ferritic steels.

Q: What does it cover?

A: It covers specimen production (weld test pieces), methods for collecting diffusible hydrogen (mercury displacement and inert‑gas headspace), measurement techniques (displaced volume or gas detector methods), calibration/linearity, result calculation/reporting and temperature controls to avoid measuring non‑diffusible hydrogen. Annexes discuss older glycerine methods and accuracy considerations.

Q: Who typically uses it?

A: Welding testing laboratories, QA/QC teams, welding engineers, consumable manufacturers, and organizations performing welding procedure qualification or investigating hydrogen‑induced cracking.

Q: Is it current or superseded?

A: ISO 3690:2018 is the current ISO edition (fourth edition, 2018) and supersedes ISO 3690:2012. National adoptions (for example EN ISO 3690:2018) were published in 2018/2019.

Q: Is it part of a series?

A: ISO 3690 is a stand‑alone test method series historically revised (editions published in 1977, 2000, 2012 and 2018). It is often used alongside other welding standards and technical reports (for example ISO/TR 17671‑1 and related welding consumables standards).

Q: What are the key keywords?

A: hydrogen, diffusible hydrogen, weld metal, arc welding, mercury displacement, headspace sampling, thermal conductivity, weld testing, IIW.