Causes And Improvement Measures Of Fastener Hydrogen Embrittlement
As the name implies, fasteners are a kind of mechanical parts used for fastening connections. They are very important and widely used. Failure of fasteners will cause serious effects. Therefore, it is necessary to strengthen the analysis of the causes of fastener failure and find the corresponding improvement measures. In the previous article, Xinchi Fastener Company shared the Causes And Improvement Measures Of the Fastener Surface Quenching Cracks. Next, according to the understanding of fastener knowledge, we will continue to introduce the fastener hydrogen embrittlement causes and improvement measures.
Causes of hydrogen embrittlement of fasteners
Fasteners are prone to hydrogen embrittlement, and hydrogen embrittlement is the main cause of fastener fracture. Hydrogen embrittlement refers to the phenomenon of hydrogen atoms entering and diffusing throughout the matrix of a material. When hydrogen atoms enter the material matrix, lattice distortion occurs in the material matrix, which destroys the original equilibrium state and is easy to crack under external force. When the external load is applied to the screw, the hydrogen atom migrates to the highly concentrated area of stress, resulting in extreme stress between the edge of the crystal boundary, leading to the fracture between the crystal particles of the fastener. When a fastener contains a critical state of hydrogen before installation, it will break within 24 hours. When hydrogen enters a fastener, it is impossible to predict when it will break.
Prevention measures for hydrogen embrittlement
Normal plating, strict removal of hydrogen. It is an important method to reduce or eliminate hydrogen embrittlement of electroplated bolts by using the reversibility of hydrogen in metal. When processing, the electroplated steel bolts are heated in the oven. The baking temperature is about 200°C, and the baking time varies according to the strength of the steel. The higher the strength, the longer the baking time. The hydrogen in the bolt material forms hydrogen overflow at high temperatures to achieve the purpose of hydrogen removal.
Low hydrogen embrittlement electroplating. It was developed in the 1960s and 1970s for the hydrogen embrittlement research of aircraft parts, including low hydrogen embrittlement cadmium plating, low hydrogen embrittlement cadmium titanium plating, low hydrogen embrittlement zinc plating and so on. Low hydrogen emittance plating requires stress relief tempering before plating. Instead of pickling with strong acid, sandblasting is used to remove oxide skin and surface dirt, or vacuum heat treatment is adopted to avoid oxide skin. In the plating process, on the one hand, the plating solution formula is adjusted, on the other hand, the current density is strictly controlled by reducing the voltage, to reduce the adsorption amount of hydrogen particles. The subsequent process also requires strict baking and hydrogen removal, and the time of hydrogen removal is at least 18h or more.
Xinchi Fastener Company is a trustworthy fastener company, especially in furniture nuts. And we are the designated fastener supplier to“STAPLE”. As a trusted fastener supplier, Xinchi Fastener Company can offer a wide range of high-quality fasteners, including tee nuts, screws, bolts, rivets, washers, etc. If you want to know more about fasteners or want to wholesale fasteners, please feel free to contact us. And then our experienced and expert service team will reply to you as soon as possible.