Manufactured under strict metallurgical control from premium certified ingots. Designed to withstand extreme mechanical tension, sulfuric environments, and high marine salinity across Portuguese industrial sites.
Alloy 20, commonly designated as Carpenter 20 Cb-3®, is an austenitic nickel-iron-chromium superalloy synthesized specifically to master aggressive environments dominated by boiling sulfuric acid (H₂SO₄). Conventional stainless steels like 304 and 316 fail precipitously in hot sulfuric acid regimes due to active dissolution of the passivation film and severe chloride-induced stress corrosion cracking (SCC).
By blending approximately 32.5% to 35% nickel with 19% to 21% chromium, along with deliberate additions of 2% to 3% molybdenum and 3% to 4% copper, Alloy 20 forms an extraordinary resilient barrier. The copper component is specifically key: it establishes pronounced resistance against reducing sulfuric acid media at temperatures up to boiling point at medium concentrations.
For Portuguese engineering teams procuring fasteners for complex chemical installations, selecting genuine Alloy 20 eliminates the persistent risks of stress cracking, localized pitting, and catastrophic crevice degradation common to high-halide, acid-heavy operating lines.
Standard fasteners sourced through unspecialized distribution channels frequently lack genuine origin validation and microstructural integrity. At our modern production works, Alloy 20 bolting undergoes rigorous hot upset-forging or CNC precision machining from centerless ground, mill-certified bars.
Grain boundaries flow uninterrupted across critical intersections—such as the transition radius underneath the hex head—drastically amplifying fatigue endurance limit and static tension tolerance over cheap turned bar equivalents. Threads are cold-rolled where possible up to M36 (1-1/2") to induce compressive stresses that counteract mechanical fatigue.
Every delivery destined for Aveiro, Sines, Lisbon, or Porto arrives flanked by EN 10204 3.1 inspect certification tracking the physical and wet chemistry results back to the original heat casting. Independent third-party inspection (TPI) through Lloyd’s Register, Bureau Veritas, or DNV for EN 10204 3.2 compliance is regularly integrated into our Portuguese export procedures.
| Alloy Grade | UNS Number | Key Chemistry (Nominal %) | Min Tensile (MPa / ksi) | Min Yield 0.2% (MPa / ksi) | Hardness (Max) |
|---|---|---|---|---|---|
| Alloy 20 (Carpenter 20) | UNS N08020 | Ni: 32.5-35.0, Cr: 19.0-21.0, Mo: 2.0-3.0, Cu: 3.0-4.0, Cb: 8×C-1.0 | 550 MPa (80 ksi) | 240 MPa (35 ksi) | 95 HRB |
| Hastelloy C-276 | UNS N10276 | Ni: Bal, Mo: 15.0-17.0, Cr: 14.5-16.5, Fe: 4.0-7.0, W: 3.0-4.5 | 690 MPa (100 ksi) | 310 MPa (45 ksi) | 100 HRB |
| Super Duplex 2507 | UNS S32750 | Cr: 24.0-26.0, Ni: 6.0-8.0, Mo: 3.0-5.0, N: 0.24-0.32 | 750 MPa (110 ksi) | 550 MPa (80 ksi) | 32 HRC |
| AISI 316L Stainless | UNS S31603 | Fe: Bal, Cr: 16.0-18.0, Ni: 10.0-14.0, Mo: 2.0-3.0 | 485 MPa (70 ksi) | 170 MPa (25 ksi) | 90 HRB |
| Titanium Grade 5 | UNS R56400 | Ti: Bal, Al: 5.5-6.75, V: 3.5-4.5, Fe: 0.40 max | 895 MPa (130 ksi) | 828 MPa (120 ksi) | 36 HRC |
Portugal’s industrial profile presents unique micro-climatic and process conditions. Our factory-direct bolting, studs, and components perform mission-critical sealing across key domestic development hubs.
Home to Portugal's largest petrochemical processing assets and deepwater liquid bulks. Alloy 20 hex head bolts and ASTM A193 B8M/Alloy 20 studs provide fail-safe fastening in sulfuric acid alkylation units, catalyst recovery circuits, and hot acid wash pipelines exposed simultaneously to aggressive process chemicals and high-salinity Atlantic coastal winds.
Portugal stands among Europe's dominant exporters of bleached kraft pulp. Bleaching towers, chlorine dioxide washers, and tall oil distillation systems operate at intense chemical aggression. Alloy 20 fasteners actively resist chlorine-sensitized pitting, sulfuric cooking liquors, and intercrystalline corrosion, providing long operating cycles between maintenance shutdowns.
In the Estarreja industrial cluster, synthetic fertilizers, nitric compounds, and downstream intermediate chemicals depend on high-pressure acid pipelines. Alloy 20 flange fasteners reliably mitigate the risk of stress corrosion cracking under thermal fluctuation, avoiding toxic emissions and satisfying stringent Portuguese environmental agency (APA) guidelines.
Portugal is aggressively accelerating decarbonization, green hydrogen production, and circular economy infrastructures, creating novel metallurgical requirements for extreme-service hardware.
Electrolyzer stacks and associated balance-of-plant acid/alkali management lines require zero-defect fastener alloys to guard against localized hydrogen embrittlement and crevice corrosion under continuous high current densities.
With multi-gigawatt offshore wind concessions underway along the Viana do Castelo and Figueira coasts, subsea junction fixtures are transitioning toward Alloy 20, Duplex 2507, and Titanium Grade 5 to combat severe splash zone corrosion.
Portuguese EPCs and plant asset integrity managers mandate unambiguous adherence to European Pressure Equipment Directives. Sourcing directly from PED-approved, TUV Rheinland-audited manufacturers avoids customs delays and project liability.
To curb multi-tiered stockist markups and extended broker lead times, procurement professionals in Porto and Lisbon are establishing direct factory relationships with specialized alloy mills providing certified heats and fast air-cargo logistics.
Combining world-class hot forging, precision cold heading, and CNC machining with accredited metallurgical laboratory testing to serve Portuguese industry without compromise.
Our quality management systems are fully certified by TUV Rheinland for pressure vessel equipment fabrication, fulfilling Annex I essential safety requirements for CE-marked apparatus throughout Portugal.
Every single Alloy 20 fastener is laser-marked with alloy grade and melt lot number. Supplied test certificates provide chemical melt breakdown, yield/tensile curves, and Charpy impact values.
We maintain comprehensive bar stocks in Alloy 20, Hastelloy C276/C22, Monel 400, Inconel 625/718, Super Duplex 2507, and Titanium Grade 5, ensuring non-standard drawing turnarounds within days.
Precision solution-annealing and hardness controls satisfy sour-service metallurgical envelopes, restricting maximum Rockwell hardness (HRC ≤ 28 / HRB ≤ 95) to prevent sulfide stress cracking.
Engineered anti-friction coatings including PTFE fluoropolymer (Xylan), electro-zinc, silver plating, and pickled-passivated treatments guarantee smooth make-up and high reusable breakout torque.
Our dedicated export packaging protocols utilize fumigated seaworthy wooden boxes, individualized thread-sleeve preservation, and bonded air-freight arrangements straight to Humberto Delgado Airport.
Essential guidance for purchasing managers, piping specialists, and mechanical contractors sourcing Alloy 20 fasteners across Portugal.