Project Description
Introduction
Super 13Cr and 1.4418 mod are low-carbon SMSS alloys in the Cr–Ni–Mo martensitic stainless steel family. Engineered as upgrades to standard AISI 420 Mod (13Cr L80), both grades incorporate reduced carbon with elevated nickel and molybdenum to deliver superior toughness, weldability, and resistance to SCC in CO₂-rich and mildly sour (H₂S) environments. They are supplied in the quenched and tempered (Q&T) condition and are qualified under NACE MR0175/ISO 15156 for sour service applications. Primary industries include oil & gas exploration, offshore engineering, hydropower, and chemical process equipment.
Similar Grades & Standards
| Standard | Designation | Remark |
|---|---|---|
| ASTM A276 / UNS | S41425 · S41426 · S41427 | 110 ksi / 95 ksi yield grades; bar & forging |
| EN 10088-3 | 1.4415 (X2CrNiMoV13-5-2) · 1.4418 (X4CrNiMo16-5-1) | European wrought products standard |
| API 5CRA / ISO 13680 | Group 1, Cat. 13-5-2 (PSL 1 & 2) | OCTG corrosion-resistant alloy tubulars |
| NORSOK M-650 Ed.4 | Super 13Cr qualified | Norwegian offshore qualification |
| BS | S165M | Near-equivalent to 1.4418 |
| SS (Sweden) | 2387 | Near-equivalent to 1.4418 |
| NACE / ISO | MR0175 / ISO 15156 Table A.19 | Sour service H₂S environmental limits |
No established direct equivalents in AMS, DIN, GOST, or JIS; EN/UNS designations serve as the global reference.
Applications
Oil & Gas / OCTG: Tubing strings, casing pipes, packer mandrels, completion tool bodies, wellhead spools, subsea flowlines, and manifold connectors — suited to sweet (CO₂) and mildly sour (H₂S) wells including HPHT conditions.
Marine & Offshore: Pump shafts, impellers, valve stems, gate valve bodies, riser clamp bolts, subsea connector pins, and splash-zone fasteners requiring moderate chloride resistance.
Power Generation & General Engineering: Hydraulic turbine shafts (Pelton / Francis runners), compressor rotor shafts, coupling sleeves, gear shafts, and high-load structural bolts.
Supply Forms & Sizes
| Form | Typical Size Range | Condition |
|---|---|---|
| Round Bar / Hollow Bar | Ø 20 – 800 mm | Q&T, peeled / turned |
| Flat Bar | T 10 – 100 mm × W up to 400 mm | Q&T |
| Plate / Slab | T 6 – 150 mm | Hot-rolled, Q&T |
| Seamless Tube / OCTG Pipe | OD 60.3 – 339.7 mm | API 5CRA, Q&T |
| Wire / Coil | Ø 0.5 – 16 mm | Annealed or cold-drawn |
Chemical Composition (wt %)
| Element | Super 13Cr S41426 API 5CRA / ISO 13680 |
1.4418 (X4CrNiMo16-5-1) EN 10088-3 |
|---|---|---|
| C | ≤ 0.03 | ≤ 0.06 |
| Cr | 11.5 – 13.5 | 15.0 – 17.0 |
| Ni | 4.5 – 6.5 | 4.0 – 6.0 |
| Mo | 1.5 – 3.0 | 0.8 – 1.5 |
| Mn | ≤ 1.0 | ≤ 1.5 |
| Si | ≤ 0.5 | ≤ 0.7 |
| N | — | ≥ 0.02 |
Mechanical Properties
| Grade / Condition | UTS Rm (MPa) | YS Rp0.2 (MPa) | El. A (%) | Hardness | KV (J) |
|---|---|---|---|---|---|
| S41426 · 95 ksi · Q&T API 5CRA / NORSOK M-650 |
≥ 724 | ≥ 655 | ≥ 18 | ≤ 27 HRC | ≥ 60 (−10°C) |
| S41425 · 110 ksi · Q&T API 5CRA / NORSOK M-650 |
≥ 862 | ≥ 758 | ≥ 16 | ≤ 32 HRC | ≥ 60 (−10°C) |
| 1.4418 · QT900 · Q&T EN 10088-3 |
900 – 1 150 | ≥ 700 | ≥ 10 | 280 – 340 HB | ≥ 60 (20°C) |
Heat treatment: Solution anneal 950 – 1 050°C (rapid quench) + temper 600 – 700°C. Properties vary with tempering temperature and section thickness.