Crack appearance of hydrogen cracks
Examples of where hydrogen cracks can form in a joint.
If a hydrogen crack is formed, it can propagate perpendicularly to the direction of the main stress that is present in the joint. The residual stresses introduced by welding are illustrationed below.
Longitudinally residual stresses in and around a butt joint.
Transversal residual stresses in and around a butt joint.
The highest level of tensile stresses in the weld metal are typically along the joint direction. Therefore, the typical behavior is that hydrogen cracks in this position start to propagate perpendicular to the joint direction. Hydrogen cracks formed in the HAZ often propagate into the unaffected parent metal. They are normally surface breaking and is often easy to identify them with the naked eye and with other types of non-destructive methods. See illustration and photo below.
Illustration of a transverse hydrogen crack. It is initiated transverse to the joint in the HAZ and as it propagates change direction longitudinal to the joint. Compare with the pictures above about residual stresses, cracks propagate perpendicular to the stress direction.
Surface breaking hydrogen crack, above and transverse to the joint. The longitudinally extension can be relativly long.
The information in this report is only applicable to SSAB’s products and should not be applied to any other products than original SSAB products.
This report provides general results and recommendations for SSAB steel products. This report is subject to SSAB’s Terms of Use. It shall be the user's responsibility to verify that the information contained herein is correct and is suitable to be used for the particular purpose and application of the user. The report is intended to be used by professional users only who possess adequate expertise, qualification and knowledge for the safe and correct use of the results and recommendations in this report. This report is provided “as is”. The use of the report is at user’s own discretion and risk and that users will be solely responsible for any use of this report. SSAB disclaims any liability for the content or potential errors of this report, including but not limited to warranties and condition of merchantability or fitness for a particular purpose or suitability for individual applications. SSAB shall not be liable for any kind of direct or indirect damages and/or costs related to or arising therefrom, whether special, incidental, consequential or directly or indirectly related to the use of, or the inability to use, the report or the content, information or results included therein.