As modern process infrastructure transitions toward higher operating pressures, harsher chloride concentrations, and deeper subsea extractions, conventional austenitic grades like AISI 304 and 316 frequently succumb to premature stress corrosion cracking (SCC) and pitting attack. Duplex 2205 Stud Bolts (UNS S32205 / UNS S31803 / EN 1.4462) represent the premier high-strength, corrosion-resistant metallurgical solution engineered specifically for safety-critical pressure vessel and piping flange connections.
Precision-manufactured in Mumbai under audited ISO 9001 systems with complete EIL and IBR product approvals. Sourced and trusted across major Middle Eastern ADNOC approved pipelines, European offshore rigs, and North American petrochemical hubs.
Global piping engineers and EPC contractors depend on accurate end-to-end fastening systems. Rajtilak Metal supplies fully matched stud bolt, nut, and washer assemblies tailored for specific ASME B16.5, ASME B16.47, and API 6A pressure classes.
Engineered to ASME B18.31.2 and DIN 976, continuously threaded from tip to tip with chamfered flat ends. Designed to absorb high tensile bolt-stretch under cyclic hydraulic pressure without stress concentrations.
Featuring unthreaded center shanks designed for valve body tie-rods, pump casing closures, and heat exchanger channel heads requiring precise shank flexibility and controlled thermal elongation.
Subsea and splash-zone ready assemblies coated with Xylan 1070, PTFE, or ceramic barrier coatings over an electroless nickel underplate to eliminate thread galling and ensure uniform torque transfer.
Verified laboratory compliance ensures every fastener stands up to the most demanding service conditions. Rajtilak Metal controls melting sources and thermal processing to prevent destructive sigma-phase precipitation.
| Parameter | UNS S31803 (Standard Duplex) | UNS S32205 (Optimized Duplex 2205) | EN / DIN Equivalent (1.4462) |
|---|---|---|---|
| Chromium (Cr) % | 21.0 – 23.0 | 22.0 – 23.0 (Tighter Control) | 21.0 – 23.0 |
| Nickel (Ni) % | 4.5 – 6.5 | 4.5 – 6.5 | 4.5 – 6.5 |
| Molybdenum (Mo) % | 2.5 – 3.5 | 3.0 – 3.5 (Enhanced Pitting Guard) | 2.5 – 3.5 |
| Nitrogen (N) % | 0.08 – 0.20 | 0.14 – 0.20 (Strengthened Matrix) | 0.10 – 0.22 |
| Carbon (C) Max % | 0.030 | 0.030 (Ultra-Low Carbon) | 0.030 |
| PREN (Cr + 3.3Mo + 16N) | ≥ 31.0 | ≥ 35.0 (Mandated for Offshore) | ≥ 33.0 – 35.0 |
| Yield Strength Rp0.2 (Min) | 450 MPa (65 ksi) | 450 MPa (65 ksi) — Typ. 520 MPa | 450 MPa |
| Tensile Strength Rm (Min) | 620 MPa (90 ksi) | 655 – 880 MPa (95 – 128 ksi) | 650 – 880 MPa |
| Elongation A5 (Min) | 25% | 25% | 25% |
| Hardness Max (NACE MR0175) | 28 HRC / 290 HBW | 28 HRC / 290 HBW | 28 HRC / 290 HBW |
| Operating Temp. Range | -50°C to +300°C (-58°F to +572°F) | -50°C to +300°C (-58°F to +572°F) | -50°C to +300°C |
The global energy landscape and marine engineering sectors are reshaping fastener specifications. Inquiries handled by Rajtilak Metal reveal several distinct long-term procurement shifts that procurement directors and project engineers must prepare for:
Fasteners utilized in Carbon Capture, Utilization, and Storage (CCUS) and supercritical CO2 reinjection lines require enhanced resistance to low-temperature embrittlement and carbonic acid pitting, positioning Duplex 2205 as the baseline standard.
Because Duplex 2205 offers more than double the design yield strength of 316/316L, structural and piping engineers can downsize bolt diameters from M36 to M27, achieving up to 35% weight reduction on offshore topside structures.
Major operators (including Aramco, Shell, ADNOC, and Chevron) are migrating to cryptographically verified 3.2 inspection dossiers with 100% positive material identification (PMI) and Charpy V-notch verification at -50°C.
International tenders increasingly require verified low-carbon scrap usage in electric arc furnaces (EAF) and optimized supply routes, an operational area where Indian manufacturers maintain a lower carbon footprint than traditional blast furnace routes.
Planning an upcoming CAPEX turnaround or major pipeline construction? Our application specialists assist engineering teams with torque calculation sheets, bolt elongation formulas, and gasket seating stress validations.
Founded in 1991 in Girgaon, Mumbai, Rajtilak Metal has grown from an indigenous component supplier into a Government of India recognised export house supplying premier EPCs across 35 countries. Our deep metallurgical competence and comprehensive inventory distinguish our manufacturing division:
In high pressure piping assemblies, counterfeit or cross-contaminated alloy bolting can lead to catastrophic blowout incidents. At Rajtilak Metal, we operate a closed-loop quality tracking workflow from incoming ingot bar to final bagged and crated stud assemblies.
Every individual Duplex 2205 stud bolt is roll-marked or dot-peen engraved on both end faces with the proprietary manufacturer hallmark, exact ASTM/ASME material designation (UNS S32205 / F51), diameter, and distinct 5-digit melt heat identification number. This stamp connects directly to the digital Mill Test Certificate, giving third-party inspectors like BV, DNV, SGS, or TÜV immediate verification.
Incoming round bars undergo OES chemical analysis before cold cutting.
Solution annealing at 1040°C–1100°C with rapid water quench under 20s.
Continuous thread contours cold-formed to ASME Class 2A / 3A fits.
Ferrite content 40-50% (ASTM E562) & Charpy test at -50°C (ASTM A370).
Strict limitation of harmful elements (Carbon ≤ 0.03%, Sulfur ≤ 0.002%) eliminates sensitization. We guarantee zero detrimental intermetallic phases (sigma, chi, laves) through ASTM A923 Method C ferric chloride testing.
Hardness capped rigorously under 28 HRC (290 HBW) in accordance with ISO 15156 sour service oil & gas criteria, giving your engineers complete peace of mind in high H2S and sour wet crude extraction.
One-stop delivery combining Duplex 2205 stud bolts with matching heavy hex nuts, hardened plain washers, and companion ASTM A182 F51 flanges — all packed inside seaworthy ISPM-15 heat-treated timber crates.
Operating across major global industrial corridors with established export logistics serving the UAE, Saudi Arabia, Qatar, Oman, Turkey, Egypt, Singapore, Malaysia, Indonesia, Italy, Poland, the United Kingdom, and the United States.
Duplex 2205 stud bolts are actively deployed where joint failure could result in catastrophic environmental pollution, personal injury, or unbudgeted shutdown costs.
Synthesized answers addressing the most critical technical, metallurgical, and commercial inquiries submitted by piping designers, quality managers, and international procurement agents.