Views: 0 Author: Site Editor Publish Time: 2023-08-08 Origin: Site
Typical fastener hydrogen embrittlement occurs in carbon steel and alloy steel materials.
The hardness of fasteners is a core parameter. When most people talk about hydrogen embrittlement, they think that the risk of hydrogen embrittlement begins when the hardness exceeds 320HV.
Tsingri Fasteners believe that the hardness of 360HV is a critical value, beyond which the risk of hydrogen embrittlement needs to be further managed, and recent research and various examples are also sufficient to support this contention.
Hydrogen embrittlement of fasteners is a delayed brittle failure process. Fracture occurs after installation and only on fasteners subjected to tensile stress, the level of tensile stress in the fastener is a decisive parameter, since fasteners are more prone to hydrogen embrittlement fracture under high load forces .
However, fasteners can fail even if the tensile strength is below the tensile load. This failure occurs sometime after the fastener is assembled. Often fasteners do not fail until hours or days after installation. Hydrogen embrittlement rarely occurs within seconds or months after assembly, and when it does, it develops instantaneously, without warning or noticeable signs. Failure of components in service is often costly and sometimes catastrophic.
One area of the fracture surface is a non-ductile fracture, while another part may exhibit a ductile fracture, which begins at the extreme end of the fastener fracture and extends over the remaining cross-section so that it can no longer bear the load force.
Brittle fracture presents fractures very similar in appearance to intergranular fractures caused by other causes.
Experienced materials engineers generally use scanning electron microscopy for inspection, and it is very important to use this inspection method to help in failure analysis and identify hydrogen embrittlement problems.
