SM125ES is a low alloy High Strength Carbon steel OCTG material suitable for medium Sour Service severity applications. SM125ES is a Sulfide Stress Cracking (SSC) resistant material extending the sour service application range of the former SM125S from 0.03 bars H2S partial pressure for SM125S to 0.10 bars H2S for SM125ES, at pH 3.50.

SSC failure mechanism is a form of Hydrogen embrittlement in combined presence of H2S, water and tensile stresses. NSSMC's experience in manufacturing SM125S which was the first 125 ksi Sour Service material released in 2003, allowed optimization of the process along with associated quality controls resulting in the extension of the sour service application range for SM125ES.

SM125ES has no equivalent in API 5CT/ISO 11960 grades and in order to achieve its superior Sour Service properties NSSMC applies a very strict QA/QC throughout its manufacturing route from Steel Making to Heat Treatment processes.