Effects of Hydrogen in Steel

Introduction: Hydrogen is a common impurity in steel, and its presence can have significant effects on the material properties. Here are the effects of hydrogen in steel:

1. Embrittlement: One of the most significant effects of hydrogen in steel is embrittlement. When hydrogen atoms are absorbed into the steel matrix, they can combine to form hydrogen molecules, which can accumulate in small voids or cracks in the material. This can cause the material to become brittle and prone to cracking or fracturing under stress.

2. Reduced Ductility: Hydrogen can also reduce the ductility of steel, which is the ability of the material to deform without breaking. This is because hydrogen atoms can occupy the interstitial sites in the steel lattice, which can hinder the movement of dislocations and reduce the plastic deformation of the material.

3. Delayed Cracking: In some cases, hydrogen can cause delayed cracking in steel. This occurs when the steel is exposed to hydrogen during or after welding, and the hydrogen diffuses into the material. The hydrogen can then accumulate in areas of high stress, such as the heat-affected zone, and cause cracking after the welding has been completed.

4. Corrosion: Hydrogen can also contribute to corrosion in steel. This is because hydrogen can react with iron atoms to form ferrous hydride, which is a less stable compound than iron. This can lead to the formation of corrosion pits and the overall degradation of the material.

Conclusion: In summary, the presence of hydrogen in steel can have significant effects on its properties, including embrittlement, reduced ductility, delayed cracking, and corrosion. Therefore, it is important to minimize the amount of hydrogen in steel during manufacturing and welding processes to ensure the material meets the required specifications.