Super 13 Chrome (UNS S41426, EN 1.4415, tradenames SM13CRS, HP2, 13CRS, Hyper II) is a low-carbon quenched-and-tempered supermartensitic stainless steel that sits at the top of the martensitic CRA OCTG pyramid. The defining chemistry — ~13% Cr, ~5% Ni, ~2% Mo, ≤0.03% C — represents a deliberate upgrade from both standard API L80 13Cr (no Ni, no Mo) and Modified 13Cr (~4% Ni, ~1% Mo). The 2% Mo + elevated Ni content does three things no other 13Cr-grade alloy can: (1) it earns a listing in NACE MR0175/ISO 15156 Table A.19 for H2S partial pressure ≤1.5 psi and pH ≥3.5 in the 95 ksi yield strength condition — the only martensitic OCTG stainless steel to achieve this with meaningful well-condition limits; (2) it maintains pitting resistance in high-chloride environments up to ~180°C, well beyond the capability of standard 13Cr, by forming a more stable Cr-oxide passive film reinforced by Mo; and (3) the ≤0.03% carbon + controlled Ni/Mo package enables weldability without post-weld heat treatment in many applications, simplifying rig-floor handling versus earlier-generation 13Cr martensitics.
SHUNFU METAL supplies Super 13 Chrome CRA pipe in L80 (80–95 ksi), L95/C95 (95–110 ksi), and P110 (110–140 ksi, sweet service only) strength grades per API 5CRA/ISO 13680 Group 1 Category 13-5-2. Manufacturing: electric arc furnace or BOF melting, seamless hot-rolling, quenched from ~980°C + double-tempered, with NORSOK M-650 Ed.4 qualifications available on request. Every pipe undergoes full-length UT to ASTM E213 / ISO 10893-10, ET to ASTM E426, PMI (XRF), hydrostatic testing at 1.5× design pressure, and receives EN 10204 Type 3.1 MTC.
Equivalent Grades — Super 13Cr & Martensitic OCTG Family
| Alloy | UNS | EN / DIN | API 5CRA | Trade Name | NACE | Max Temp (°C) |
|---|---|---|---|---|---|---|
| Super 13Cr | S41426 | 1.4415 X2CrNiMoV13-5-2 |
Gr.1 Cat. 13-5-2 L80 / L95 / P110 |
SM13CRS / HP2 13CRS / Hyper II |
✅ Table A.19 H₂S≤1.5 psi, pH≥3.5 (95 ksi grade) |
~180 |
| Super 13Cr (Orig.) | S41425 | — | Gr. 1 Cat. 13-5-2 | 13Cr-5Ni-2Mo | ✅ Table A.19 H₂S≤1.5 psi |
~175 |
| Modified 13Cr | — (proprietary) | — | Gr. 1 Cat. 13-5-2 L80 / L95 |
13CRM / HP1 SM13CRM |
❌ Sweet CO₂ only | ~180 |
| Std. 13Cr L80 | S42000 | 1.4021 / X20Cr13 | 5CT Gr. 2 L80 Type 13Cr |
13Cr / 420 Mod | ❌ Sweet CO₂ only | ~150 |
Oil & Gas Applications of Super 13 Chrome
Mildly Sour CO₂ HPHT Production Tubing
The primary application. Super 13Cr is NACE MR0175 Table A.19 listed for H₂S ≤1.5 psi, pH ≥3.5 at 95 ksi — the only martensitic OCTG alloy with formal sour qualification. Covers deep gas wells with CO₂ + trace H₂S where standard 13Cr would suffer SSC and duplex is cost-prohibitive.
HPHT Production Casing & Liner
110 ksi grade provides the strength envelope for deep casing strings in conditions beyond API 5CT carbon steel and standard 13Cr limits. Maintains corrosion resistance through the full-temperature production cycle up to ~180°C.
High-Chloride CO₂ Service
2% Mo in Super 13Cr stabilizes the Cr-O passive film against chloride attack, a known failure mode of standard 13Cr above ~50,000 mg/L Cl⁻ at elevated temperature. SM13CRS field data demonstrates pitting-free service at [Cl⁻] where 13Cr L80 develops localized corrosion within weeks.
Downhole Completion Equipment
Packers, safety valves, mandrels, landing nipples, and gas-lift equipment in CO₂-bearing wells requiring the most corrosion-resistant martensitic option available. Low-carbon chemistry allows weld repairs without mandatory PWHT.
Base Pipe for Sand Screens
Unconsolidated reservoirs with CO₂ + chlorides. Super 13Cr base pipe provides the mechanical integrity and H₂S tolerance that premium wire-wrap and mesh-rite screens demand, without the cost of nickel-based CRA base pipe.
Expandable Tubulars & Geothermal
The martensitic structure provides favorable expansion characteristics combined with corrosion resistance for solid-expandable tubular applications. Also specified for geothermal wells producing CO₂-rich brine at ~150–180°C.
Supply Dimensions, Specifications & Delivery Condition
| CRA Pipe Dimensional Range | |
|---|---|
| O.D. Range (seamless) | 2-1/16″ – 10-3/4″ (52.4 – 273.1 mm) |
| O.D. Range (expanded) | Up to 16″ (406.4 mm) — Nippon SM13CRS |
| Wall Thickness | Per API 5CT weight schedule, up to 1.925″ |
| Lengths | R1, R2, R3 (per API 5CT / ISO 11960) |
| End Finish | Plain end, Premium threads, API threads |
| Specifications & Certifications | |
|---|---|
| Product Spec | API 5CRA / ISO 13680 Group 1 Category 13-5-2; API 5CT / ISO 11960 |
| Bar Spec | ASTM A276 S41426 |
| Sour Service | NACE MR0175 / ISO 15156 Table A.19 (95 ksi condition) |
| NORSOK | M-650 Ed.4 qualified manufacturers available |
| PED | 2014/68/EU Annex I section 4.3 |
| MTC | EN 10204 Type 3.1 as standard |
| Proprietary Spec | Nippon Steel TGP-2218 (SM13CRS series); Vallourec 13CRS |
| Heat Treatment | Quenched (~980°C) + double-tempered |
| NDE Package | UT (ASTM E213 / ISO 10893-10), ET (ASTM E426), PMI (XRF), hydrostatic 1.5× design |
Chemical Composition — Super 13 Chrome UNS S41426 / EN 1.4415
| Element | S41426 (API 5CRA) | SM13CRS (Nippon) | HP2 (Typical) | SHUNFU Internal Control | Purpose in Alloy |
|---|---|---|---|---|---|
| C | ≤0.03 | ≤0.03 | ≤0.02 | ≤0.025 | Martensite hardenability, weldability — low C suppresses Cr₂₃C₆ sensitization |
| Mn | ≤1.00 | ≤0.50 | ≤0.50 | ≤0.50 | Deoxidizer, hot-workability |
| Si | ≤0.50 | ≤0.50 | ≤0.50 | ≤0.40 | Deoxidizer; excess degrades toughness |
| P | ≤0.020 | ≤0.020 | ≤0.020 | ≤0.015 | Impurity — controlled for SSC resistance |
| S | ≤0.005 | ≤0.005 | ≤0.003 | ≤0.003 | Impurity — ultra-low for SSC; MnS inclusions act as pitting initiation sites |
| Cr | 11.50–13.50 | 11.50–13.50 | 12.00–13.00 | 12.00–13.50 | Cathodic passive film (Cr₂O₃) — primary corrosion barrier; martensite former |
| Ni | 4.50–6.50 | 5.00–6.50 | 4.50–5.50 | 5.00–6.00 | Austenite stabilizer — prevents δ-ferrite, improves toughness and CO₂ corrosion resistance |
| Mo | 1.50–3.00 | 1.50–3.00 | 2.00–2.50 | 2.00–2.80 | Pitting resistance (Cl⁻), SSC resistance, high-temperature strength rentention |
| Ti | 0.01–0.50 | — | — | ~0.01–0.30 | Grain refiner — TiC/TiN pin austenite grain boundaries, refine martensite lath structure |
| V | — (≤0.50 in S41426 variant) | — | — | ~0.10–0.40 | Secondary carbide former — V₄C₃ precipitates temper strength without degrading SSC resistance |
| Fe | Balance | Balance | Balance | Balance | Matrix — martensitic iron |
Mechanical Properties — Super 13 Chrome S41426 per API 5CRA / ISO 13680
| Grade | YS (ksi / MPa) | TS (ksi / MPa) | Elong. (%) | HRC (Max) | CVN (ft·lb / J) | NACE MR0175 |
|---|---|---|---|---|---|---|
| L80 (80 Grade)Sour + CO₂ | 80–95 / 552–655 | ≥90 / ≥621 | Fn of specimen | ≤27 | ≥44 / ≥60 | ✅ Table A.19 H₂S ≤1.5 psi, pH ≥3.5 |
| L95 / C95Sour + CO₂ | 95–110 / 655–758 | ≥105 / ≥724 | ≥18–20 | ≤27 | ≥44 / ≥60 | ✅ Table A.19 H₂S ≤1.5 psi, pH ≥3.5 |
| P110 (110 Grade)Sweet CO₂ only | 110–140 / 758–965 | ≥115 / ≥793 | ≥15 | ≤32 | ≥44 / ≥60 | ❌ Not for sour |
| Physical Properties (Typical — Nippon SM13CRS-110) | ||||||
|---|---|---|---|---|---|---|
| Property | 25°C | 50°C | 100°C | 150°C | 200°C | 250°C |
| Density (kg/m³) | 7720 | 7710 | 7700 | 7690 | 7680 | 7670 |
| Young’s Modulus (GPa) | 202 | 201 | 198 | 196 | 193 | 189 |
| Thermal Conductivity (W/m·K) | 15.7 | 15.9 | 16.8 | 17.8 | 18.5 | 19.3 |
| CTE (×10⁻⁶/°C) | — | 11.0 | 10.7 | 10.7 | 10.8 | 10.9 |
| YS De-rating (% RT) | — | 96.3 | 92.2 | 89.4 | 87.0 | 85.1 |
| TS De-rating (% RT) | — | 96.5 | 92.8 | 89.0 | 87.2 | 85.4 |
Need Super 13Cr S41426 pipe to the specification above?
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