Nace Pipe

 This standard applies to all components of equipment exposed to sour environments, where failure by SSC or SCC would (1) prevent the equipment from being restored to an operating condition while continuing to contain pressure, (2) compromise the integrity of the pressure-containment system, and/or (3) prevent the basic function of the equipment from occurring.  Materials selection for items such as atmospheric and low-pressure systems, water-handling facilities, sucker rods, and subsurface pumps are covered in greater detail in other NACE International and API documents and are outside the scope of this standard. 

1.4 MR0175 Application 

Sulfide stress cracking (SSC) is affected by the following factors: 

(1) metallurgical condition and strength, which are affected by chemical composition, heat treatment, cold work, and 

microstructure;

2) hydrogen ion concentration (activity) (pH) of the water phase; 

(3) H2S partial pressure, which is a function of the H2S concentration and total absolute pressure; 

(4) total tensile stress (applied plus residual); 

(5) temperature; 

(6) exposure duration;  

(7) galvanic effects; 

(8) chloride or other halide ion concentration;  

(9) oxidants; 

(10) non-production fluids (including those used for acid stimulation and for packer fluids). 

Stress corrosion cracking (SCC) in sour service is affected by the following factors: 

(1) metallurgical condition and strength, which are affected by chemical composition, cold work, heat treatment, and microstructure; 

(2) hydrogen ion concentration (activity) (pH) of the water 

phase; 

(3) H2S partial pressure, which is a function of the H2S concentration and total absolute pressure;  

(4) total tensile stress (applied plus residual); 

(5) temperature; 

(6) exposure duration;  

(7) galvanic  effects; 

(8) chloride or other halide ion concentration; 

(9) oxidants;  

(10) non-production fluids (including those used for acid  stimulation and for packer fluids).