Alloy steel fasteners, especially steels with a relatively high alloy composition, are prone to cracks under stress.
Initially, craters are generally formed on the surface, and then further corrosion is generated, which causes the crack to propagate. The rate is determined by the stress on the bolt and the fracture toughness of the material. Fracture occurs when the remaining material functions to withstand the applied stress.
High-strength steel fasteners are generally more susceptible to hydrogen embrittlement than Rockwell hardness. Hydrogen embrittlement is the main cause of fastener breakage. Hydrogen embrittlement is a phenomenon in which hydrogen atoms enter and diffuse throughout the matrix of a material. When a hydrogen atom enters a matrix of a material, the matrix of the material undergoes lattice distortion, which destroys the original equilibrium state, and thus is easily cracked by an external force. When an external load is applied to the screw, the hydrogen atoms migrate to a highly concentrated region of stress, causing extreme stress between the edges of the crystal boundaries, which causes cracks between the crystal grains of the fastener. When a fastener contains a critical state of hydrogen prior to installation, it typically breaks within. It is impossible to predict when a break will occur when hydrogen enters a fastener.
Therefore, when designing the relevant fasteners, designers should specify suppliers that have special processes and minimize the potential for hydrogen embrittlement. Other factors The joint fracture is not always directly related to catastrophic fastener breakage.
Extra Heavy Duty Caster
Extra Heavy Duty Caster
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