HYDROGEN EMBRITTLEMENT

I want to explain what Hydrogen Embrittlement is and how to avoid it. First choose a knowledgeable fastener supplier that utilizes an experienced plater. Hydrogen Embrittlement describes a high-strength fastener that has absorbed an excessive amount of hydrogen during the electroplating process. Once absorbed, the excess hydrogen gets trapped within pockets in the fastener's structure. These trapped hydrogen atoms can cause the metal to become brittle, resulting in the fastener breaking after installation. Embrittlement fractures most commonly appear directly underneath the head. The amount of hydrogen introduced to the fastener depends on how platers choose to clean and electroplate, whereby certain processes have more hydrogen than others and should be avoided whenever possible. Acid pickling, where a fastener is cleaned and descaled, is one of the worst offenders. During the acid pickling process, there's an increased chance of a chemical reaction yielding hydrogen, which diffuses throughout the microstructure causing it to weaken under pressure and should be avoided. Then during the electroplating process, if the fastener was first subjected to acid pickling, the electric current and zinc coating seal the surface of the part, trapping the absorbed hydrogen inside. So, how do we reduce hydrogen embrittlement? It is necessary to apply the process referred to as 'Baking', also known as 'Low Hydrogen Annealing', as this process involves heating newly plated fasteners in an oven for a prescribed amount of time, allowing the excess hydrogen atoms to escape the fastener's steel structure . The baking process is generally around 400 degrees Fahrenheit for at least 4 hours.