Patriot Bolt machines Duplex 2205 stud bolts from certified ASTM A276 or A479 round bar for offshore, pipeline and chloride service. Duplex 2205 (UNS S32205 / S31803) is a 22% chromium ferritic-austenitic stainless steel with about twice the yield strength of 316 and far better resistance to chloride pitting and stress-corrosion cracking.
We make 2205 studs to the specification on your purchase order or to your drawing. Every order ships with mill test reports traceable to the heat.
Duplex 2205 Stud Bolts at a Glance
- Also called
- 2205 · UNS S32205 / S31803 · F51 / F60 · W.Nr. 1.4462
- Material specs
- ASTM A276 / A479 bar · ASTM A1082 bolting · NACE MR0175 / ISO 15156-3
- Strength
- 95 ksi min tensile (S32205), 65 ksi min yield (ASTM A1082)
- Corrosion
- PREN about 35; resists chloride pitting and SCC
- Configurations
- Fully threaded, double-end and tap-end
Why Engineers Specify Duplex 2205 Stud Bolts
2205 is the workhorse duplex grade. It sits between 316 stainless and super duplex 2507, giving a big step up in strength and chloride resistance over 316 at lower cost than 2507.
- Strength. A 65 ksi minimum yield is about twice that of annealed 316 and B8 Class 1 studs.
- Chloride resistance. A PREN of about 35 resists pitting and crevice corrosion in many seawater and brine services.
- Stress-corrosion cracking. The duplex structure resists the chloride cracking that affects austenitic stainless.
- Sour service. Duplex stainless steels are listed in NACE MR0175 / ISO 15156-3, within the limits that standard sets.
Duplex 2205 Stud Bolt Specifications
2205 bar is produced to ASTM A276 or A479. ASTM A1082 covers duplex stainless steel bolting for pressure vessel and piping service.
| UNS | Tensile, min | Yield, min | Elong., min | Hardness, max |
|---|---|---|---|---|
| S32205 | 95 ksi | 65 ksi | 25% | 30 HRC / 290 HB |
| S31803 | 90 ksi | 65 ksi | 25% | 30 HRC / 290 HB |
Values per ASTM A1082. Most modern bar is dual certified to S32205 and S31803. Duplex steels lose toughness at high temperatures and are generally kept below about 570 °F. Check your design code for the limit.
Duplex 2205 Chemical Composition
| Element | Weight % (S32205) |
|---|---|
| Chromium | 22.0–23.0 |
| Nickel | 4.5–6.5 |
| Molybdenum | 3.0–3.5 |
| Nitrogen | 0.14–0.20 |
| Manganese | 2.00 max |
| Silicon | 1.00 max |
| Carbon | 0.030 max |
| Phosphorus | 0.030 max |
| Sulfur | 0.020 max |
| Iron | Balance |
Limits per ASTM A1082 for UNS S32205. PREN = %Cr + 3.3 × %Mo + 16 × %N. The mill test report for your heat is the controlling document.
Stud Configurations
- Fully threaded studs, threaded end to end, for flange bolting where grip length varies.
- Double-end studs, threaded on both ends with an unthreaded center.
- Tap-end studs, with one end made to thread into a tapped hole.
Duplex stainless can gall. Use a compatible thread lubricant.
Applications and Industries
- Offshore and pipelines: Topside, seawater and produced-water flange studs. See Oil & Gas.
- Chemical and desalination: Chloride-bearing process and brine systems. See Petrochemical & Refining.
- Pulp, paper and industrial: Bleach plant, pump and valve bolting. See Industrial & Manufacturing.
Certification and Traceability
Patriot Bolt is ISO 9001:2015 certified. Each Duplex 2205 order includes mill test reports traceable to the heat, along with a certificate of conformance to the specification on your purchase order.
For more severe chloride service, see Super Duplex 2507 stud bolts.
Compare Duplex 2205 with other bolting grades in our Fastener Materials Matrix.
Duplex 2205 Stud Bolts FAQ
How does 2205 compare with 316 stainless studs?
2205 has about twice the minimum yield strength of annealed 316 and much better resistance to chloride pitting and stress-corrosion cracking.
When should I step up from 2205 to Super Duplex 2507?
When chloride levels, temperature or required strength are beyond what 2205 handles. 2507 has a PREN above 40 and an 80 ksi minimum yield.
What is the difference between S31803 and S32205?
S32205 is a tighter version of S31803 with higher minimums for nitrogen and molybdenum. Most 2205 bar today is dual certified to both.
Do you make matching nuts?
Yes. We also machine Duplex 2205 nuts and heavy hex bolts.
Request a Quote
Send us the stud configuration, diameter, length, thread, specification and quantity, or upload your drawing. Our team will confirm the material and lead time. Call (281) 581-0176 or request a quote.
Also in Duplex 2205: Heavy hex bolts · Nuts · Socket head cap screws · All stud bolts