What is hydrogen embrittlement of fasteners?

Hydrogen embrittlement is a very serious problem in the fastener industry, including building fasteners, roofing screws, bimetal screws, and coated screws. It will change the structure of the material and cause a sharp decline in mechanical properties.

Hydrogen embrittlement was reported as early as more than a hundred years ago (1875). After decades of in-depth research, industry experts have found that hydrogen embrittlement still has many uncertainties.

There are two types of hydrogen embrittlement

1. Environmental type, hydrogen embrittlement failure is caused by hydrogen produced in the natural environment, and most of the cases are caused by corrosion.

2. The most common hydrogen embrittlement failure originates from hydrogen generated during the manufacturing process, and this type is identified as intrinsic hydrogen embrittlement.

Not all metals and alloys are affected by hydrogen embrittlement, and the complexity of hydrogen embrittlement fractures exceeds the normal fracture process.

Materials most susceptible to hydrogen embrittlement include high-strength steels, titanium, and aluminum alloys.

The ingress of hydrogen into metals and alloys is clearly an important factor in the formation of hydrogen embrittlement. The process itself is quite complex and the rate of hydrogen ingress depends on many variables.

Sources of hydrogen besides corrosion include steelmaking processes, improper lubricant breakdown, heat treatment environments, welding processes, and machining in humid environments, the vast majority of embrittlement risks seem to occur on electrochemical surfaces During processing such as pickling and electroplating.