Our Critical Service grades offer a cost effective alternative in case of mild sweet corrosion
An economical alternative to CRAs
Tenaris provides oil & gas customers the Critical Service (CS) proprietary steel grades to resist corrosion produced under the presence of CO2 where Corrosion Resistant Alloys are not economically justified.
Our offer of CS grades can be divided in two basic metallurgical designs, characterized by their Chromium content.
- 1%Cr steels are recommended for mild sweet corrosion, with low CO2 partial pressures and medium to high water cut.
- 3%Cr steels. Micro alloyed to increase strength, also tolerate a higher amount of CO2 for milder conditions than the ones requiring martensitic stainless steels (Cr13).
CS are carbon steels designed for improved performance in these environments. The performance can be further improved when combined with TenarisHydril premium connections or a proper inhibitor program.
CS grades are also being used in water injection applications, as a good improvement for carbon
steels, although retaining some of their limitations.
The corrosion film, although not producing complete protection, provides a higher resistance
level when compared with standard API L80 grade, always in combination with a proper water
treatment in order to provide controlled dissolved oxygen levels in the injected water.
1% Chromium Mechanical Properties
| grade |
Minimum Yield Strength (Ksi) |
Maximum Yield Strength (Ksi) |
Minimum Tensile Strength (KSI)
|
| TN 55CS |
55 |
80 |
80 |
| TN 70CS |
70 |
100 |
95 |
| TN 75CS |
75 |
105 |
100 |
3% Chromium Mechanical Properties
| grade |
Minimum Yield Strength (Ksi) |
Maximum Yield Strength (Ksi) |
Minimum Tensile Strength (KSI)
|
Maximum Hardness Reading (HRC) |
| TN 80Cr3 |
80 |
95 |
95 |
23 |
| TN 95Cr3 |
95 |
110 |
105 |
- |
| TN 110Cr3 |
110 |
140 |
125 |
- |