API 571 Certification (Corrosion & Materials) Practice Test

Which materials are most susceptible to hydrogen absorption through titanium hydriding?

1. 300 series stainless steel

2. Carbon steels

3. Titanium and titanium alloys

4. Aluminum alloys

The correct answer is: Titanium and titanium alloys

Titanium and titanium alloys are known for their ability to absorb hydrogen, leading to a phenomenon known as titanium hydriding. When hydrogen is introduced into titanium, it can form titanium hydride, which alters the mechanical properties of the material, typically resulting in embrittlement. This susceptibility is primarily due to the unique crystal structure of titanium, which has a high solubility for hydrogen at certain temperatures and pressures. The formation of titanium hydride can affect the ductility and toughness of the material, making it essential to monitor and control hydrogen exposure in applications where titanium is used. In contrast, while other materials like stainless steels, carbon steels, and aluminum alloys can also interact with hydrogen, they do not exhibit the same level of susceptibility to hydriding as titanium and its alloys. Therefore, titanium and titanium alloys stand out as the most affected materials when it comes to hydrogen absorption issues through hydriding.