Table of Contents
- SMO 254 / 6MO Overview
- Technical Specifications
- Chemical Composition & Mechanical Properties
- Types of SMO 254 / 6MO Hex Bars
- Key Advantages of SMO 254 / 6MO Hex Bars
- Key Applications of SMO 254 / 6MO Hex Bars
- Quality Assurance & Inspection
- Global Export Markets
- Frequently Asked Questions
- Contact Aurum Overseas
SMO 254 / 6MO Overview
Engineered with 6.0–6.5% molybdenum and a high nitrogen-alloyed matrix, UNS S31254 Hex Bars offer outstanding pitting resistance (PREN ≥ 42) in aggressive seawater and acid streams. Aurum Overseas is a trusted SMO 254 Hex Bars Supplier and 6 Moly Alloy Hex Bars Supplier, delivering solution-annealed solid hexagon stock for demanding offshore and industrial equipment.
As a certified SMO 254 Hex Bars Exporter and 6 Moly Alloy Hex Bars Exporter, we stock precision cold-drawn SMO 254 Bright Hex Bars for CNC fittings alongside heavy SMO 254 Forged Hex Bars for high-load pressure valves. These 6 Moly Alloy Hex Bars provide twice the yield strength of standard 300-series stainless steels.
We export certified nickel-moly hexagon stock compliant with ASTM A276 and ASTM A479 standards directly to offshore platforms, desalination units, and chemical processing plants across the USA, UK, Germany, UAE, Saudi Arabia, and global markets.
Technical Specifications
| Technical Parameter | Specification Standard |
|---|---|
| Material Specifications | ASTM A276, ASTM A479, ASTM A182, EN 10088-3 |
| UNS Designation | UNS S31254 |
| EN Designation | X1CrNiMoCuN20-18-7 |
| Across-Flats (AF) Size Range | 6.0 mm to 100.0 mm (1/4" to 4" Hexagon) |
| Length Options | 1,000 mm to 6,000 mm, Precision Sawing Cut-to-Length |
| Surface Finishes | Cold Drawn, Centerless Ground, Bright Annealed, Hot Forged |
| Heat Treatment Condition | Solution Annealed (1150 °C to 1200 °C, Rapid Water Quench) |
| Dimensional Tolerances | ASTM A484 / ISO 286-2 (h9, h10, h11 hex profile tolerances) |
| HSN Code | 72042190 |
Chemical Composition & Mechanical Properties
Equivalent Standards
| Standard / Grade | Werkstoff Nr. | UNS Designation | EN Standard | SIS |
|---|---|---|---|---|
| SMO 254 / 6MO | 1.4547 | S31254 | X1CrNiMoCuN20-18-7 | 2378 |
Chemical Composition (%)
| Element | Specification Range (UNS S31254) |
|---|---|
| Carbon (C) | 0.02 max |
| Chromium (Cr) | 19.5 – 20.5 |
| Nickel (Ni) | 17.5 – 18.5 |
| Molybdenum (Mo) | 6.0 – 6.5 |
| Nitrogen (N) | 0.18 – 0.22 |
| Copper (Cu) | 0.50 – 1.00 |
| Manganese (Mn) | 1.00 max |
| Silicon (Si) | 0.80 max |
| Phosphorus (P) | 0.03 max |
| Sulfur (S) | 0.01 max |
| Iron (Fe) | Balance |
Mechanical & Physical Properties
| Property Parameter | Metric Units | Imperial / Standard Units |
|---|---|---|
| Density | 8.0 g/cm³ | 0.289 lb/in³ |
| Melting Point Range | 1320 °C – 1390 °C | 2410 °F – 2530 °F |
| Tensile Strength (Min) | 650 MPa | 94 ksi |
| Yield Strength (0.2% Offset, Min) | 300 MPa | 43.5 ksi |
| Elongation (Min) | 35 % | 35 % |
| Hardness (Max) | 270 HBW | Brinell Hardness |
| Modulus of Elasticity | 195 GPa | 28.3 x 10³ ksi |
| Reduction of Area (Min) | 50 % | 50 % |
Types of SMO 254 / 6MO Hex Bars
Aurum Overseas supplies SMO 254 / 6MO (UNS S31254) hex bars in precision bright and heavy forged conditions for marine and acidic service.
SMO 254 Bright Hex Bars
SMO 254 Forged Hex Bars
Key Advantages of SMO 254 / 6MO Hex Bars
High Chloride Pitting Defense
High molybdenum and nitrogen content produce a PREN ≥ 42 rating, eliminating localized pitting in stagnant seawater.
Superior Mechanical Yield
Nitrogen strengthening delivers over 300 MPa yield strength, permitting reduced wall thickness and lighter component weight.
Crevice Corrosion Protection
Balanced copper addition provides extra resistance to crevice corrosion under tight seals and biofouling layers.
Intergranular Corrosion Immunity
Ultra-low carbon level (0.02% max) prevents chromium carbide precipitation along grain boundaries during welding.
Key Applications of SMO 254 / 6MO Hex Bars
| Industry | Applications | Operational Benefit |
|---|---|---|
| Offshore & Marine | Subsea hydraulic manifold fittings, pump shafts, valve stems | High structural performance in warm, aerated chloride and seawater streams. |
| Pulp & Paper Bleaching | Bleach plant washer bolts, drum shaft fasteners, filter plugs | Prevents localized cracking in aggressive chlorine dioxide bleach environments. |
| Flue Gas Desulfurization (FGD) | Scrubber nozzle fittings, mist eliminator support pins, hex fasteners | Withstands severe acidic condensate and high-chloride slurry exposure. |
| Desalination Plants | High-pressure RO pump couplings, feed manifold hex plugs | Eliminates crevice attack at high operating pressures in concentrated brine. |
Quality Assurance & Inspection
As a professional SMO 254 Hex Bars Exporter and 6 Moly Alloy Hex Bars Exporter, Aurum Overseas conducts strict non-destructive and mechanical testing on every batch:
- Positive Material Identification (PMI): 100% XRF testing to verify exact 6.0–6.5% molybdenum and 17.5–18.5% nickel composition.
- Corrosion Testing: Intergranular corrosion tests per ASTM A262 Practice E and pitting tests per ASTM G48 Method A.
- Mechanical & Hardness Testing: Tensile, yield, elongation, and Brinell hardness verification per ASTM A276.
- Ultrasonic Examination (NDT): Volumetric ultrasonic inspection per ASTM A388 to guarantee zero internal voids in forged hex stock.
Global Export Markets
As an established SMO 254 / 6MO Hex Bars Exporter, Aurum Overseas supplies fully certified UNS S31254 Hex Bars to global offshore, desalination, and chemical processing facilities:
USA
Canada
Mexico
Germany
United Kingdom
France
Italy
Netherlands
Belgium
Spain
Poland
UAE
Saudi Arabia
Qatar
Kuwait
Oman
Bahrain
Frequently Asked Questions
6 Moly alloys contain 6.0–6.5% molybdenum and added nitrogen, providing more than double the yield strength and far superior resistance to chloride pitting and crevice corrosion compared to 316L.
SMO 254 (UNS S31254 / W.Nr. 1.4547) hex bar stock is produced in full compliance with ASTM A276, ASTM A479, and EN 10088-3 standards.
Yes, the ultra-low carbon chemistry (0.02% max) allows welding without intergranular chromium carbide precipitation, though matching high-moly filler metal (such as Alloy 625) is recommended to preserve weld seam corrosion resistance.
Hexagonal profiles feature pre-formed parallel flat surfaces, reducing machining passes when making high-torque bolts, valve seats, and threaded fittings.
Contact Aurum Overseas
Partner with an established SMO 254 Hex Bars Supplier and global 6 Moly Alloy Hex Bars Exporter for certified stock, custom sawing, and fast international dispatch.