Saturday, March 27, 2010
Sulfide -stress cracking is basically a hydrogen-embrittlement phenomenon .Atomic hydrogen enters the steel to cause cracking. The hydrogen is generated on the surface of the steel because of a corrosion reaction. Iron reacts with h2s to form iron sulfide and hydrogen .This hydrogen is generated in atomic form on the steel surface ,where it can either combine to form molecular hydrogen and leave the surface as bubbles or diffuse into steel .This latter process may result in hydrogen embrittlement .Hydrogen sulfide prevents hydrogen recombination & thus promote entry of atomic hydrogen into steel .It is important to note that water must be present for this mechanism to occur ;without it SSC will not be observed ,because the ionization of the hydrogen sulfide is required.
Following is a lecture presentation on NACE Standard MR0175 - Petroleum and Natural Gas Industries – Materials for use in H2S-containing Environments in Oil and Gas Production.
- NACE MR0103 versus MR0175
- Common FAQs Related to NACE Standard MR0175 / ISO 15156
- Material Selection... USER Responsibility
- Error in NACE MR0175 / ISO 15156
- Guideline on Use of MR0175 / ISO15156
- What are the concerns related to H2S ?
- Safety Moment with H2S
- Pyrophoric Fire
- Pitting Corrosion - Mechanism & Prevention