{"id":23668,"date":"2023-11-20T16:26:51","date_gmt":"2023-11-20T16:26:51","guid":{"rendered":"https:\/\/www.hawkins.biz\/?post_type=insight&p=23668"},"modified":"2025-07-30T08:54:22","modified_gmt":"2025-07-30T07:54:22","slug":"hydrogen-embrittlement-in-metals","status":"publish","type":"insight","link":"https:\/\/www.hawkins.biz\/insight\/hydrogen-embrittlement-in-metals\/","title":{"rendered":"Hydrogen Embrittlement \u2013 how can a gas make a metal brittle?"},"content":{"rendered":"\t\t
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Hydrogen, from its explosive potential to its benign, life giving properties after reacting with oxygen, is one of the most dynamic elements.<\/p>

A lesser-known phenomenon is hydrogen\u2019s ability to embrittle certain metals. Typically, when we think of the properties of metals, their ability to bend and stretch (often substantially) before they break is one thing that comes to mind; this is termed \u2018ductility\u2019. More formally, tensile ductility is the amount of deformation a material undergoes before fracture occurs when the item is pulled to failure. Deforming prior to failure is nearly always a good feature, because it can warn people of an impending catastrophic failure.<\/p>

Hydrogen embrittlement causes some metals to lose their ductility, become brittle, and fracture, and is a well-documented occurrence that can result in the apparent sudden failure of a component.<\/p>

Hydrogen embrittlement and Hydrogen Induced Cracking (HIC) are two of several documented mechanisms by which hydrogen can damage materials. HIC, closely related to hydrogen embrittlement, is hydrogen damage that produces flaking and blistering of materials.<\/p>

A stress is required for an item to fail by hydrogen embrittlement. The stress can either be applied or residual. An example of applied stress would be the tensile stress on a bolt, when used to clamp two plates together in service, or the tension in a wire from which a weight is hung. Residual stress can come from rapid cooling during heat treatment, welding, or deformation, as well as from manufacture and processing.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Tensile stress -v- Residual stress on metals<\/em><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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A frequent feature with hydrogen embrittlement is a delay between a component\u2019s seemingly successfully initial service life (e.g. tightening of the bolts to the required torque during assembly did not result in them breaking) and its subsequent sudden failure (fracture of the threaded bolt shaft, some hours, days or weeks after it was installed).<\/p>

I have known of assembled items, whilst awaiting shipment at a port to their final customer, to be brought back to the manufacturing facility, because sample testing of the same production batch of bolts over several days had found the bolts to crack due to hydrogen embrittlement.<\/p>

Hydrogen is ubiquitous in the environment, as well as in many manufacturing environments. Common sources of hydrogen are:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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