Fastener Materials &
Alloy Grades
From standard stainless steel to exotic high-performance alloys — SM Fastners manufactures in any material grade to meet your project’s chemical, mechanical, and temperature requirements. Every heat lot is traceable and documented.
PMI Verified Material
EN 10204 Type 3.1 / 3.2 MTCs
NABL Accredited Lab Reports
Heat Number Traceability
Stainless Steel
Duplex & Super Duplex
Inconel
Hastelloy
Monel
Incoloy
Titanium
Brass & Copper
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Austenitic, martensitic and ferritic stainless steel grades — the most widely specified material for corrosion-resistant industrial fasteners globally.
Most Popular · 1,500+ SKUs
Most Popular
SS 304 · 316 · 316L
Austenitic · Grades 304 / 316 / 316L / 317L / 310S / 321
Stainless Steel (Austenitic)
The most widely used stainless family. SS 304 offers excellent general corrosion resistance; SS 316/316L adds molybdenum for superior chloride and acid resistance — the standard choice for marine, food processing, pharmaceutical and chemical plant fasteners worldwide.
Tensile Strength
515 – 760 MPa
Temp Range
–200°C to +800°C
Density
7.93 g/cm³
Hardness
≤ 200 HB (Annealed)
ASTM A193 B8/B8M
ASTM A194 8/8M
DIN 1.4301
DIN 1.4401
ISO 3506
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Specialty Grades
SS 410 · 420 · 904L
Martensitic & High-Alloy · Grades 410 / 420 / 430 / 904L / 254 SMO
Stainless Steel (Specialty)
Martensitic grades (410/420) provide higher hardness and wear resistance via heat treatment — ideal for valve stems and pump shafts. Grade 904L and SMO 254 deliver superior resistance to sulphuric acid and pitting, used in chemical and pulp & paper industries.
Tensile Strength
620 – 1000 MPa
Hardness (410 HT)
Up to 330 HB
PREN (904L)
~36
Mo Content (904L)
4.0 – 5.0%
ASTM A276
ASTM A193 B6
DIN 1.4002
UNS S90400
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Two-phase ferritic-austenitic microstructure offering superior strength and corrosion resistance — the premium choice for offshore and chemical plant fastening.
Offshore Grade · 400+ SKUs
Offshore Standard
2205 · S31803 · S32205
Duplex · UNS S31803 / S32205 · 1.4462
Duplex Stainless Steel 2205
The most widely used duplex grade. Offers twice the yield strength of standard 304/316 with superior chloride stress corrosion cracking resistance. Extensively used in oil & gas platforms, subsea equipment, chemical plants and desalination systems. PREN of 35–40.
Yield Strength
≥ 450 MPa
Tensile Strength
620 – 880 MPa
PREN
35 – 40
Temp Range
–50°C to +300°C
ASTM A182 F51
ASTM A276
NACE MR0175
ISO 15156
EN 10088-3
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Maximum Corrosion Resistance
2507 · S32750 · S32760
Super Duplex · UNS S32750 / S32760 · 1.4410 / 1.4501
Super Duplex Stainless Steel 2507
Maximum performance duplex with PREN exceeding 40. Exceptional resistance to pitting, crevice corrosion, stress corrosion cracking and erosion in severe chloride and acid environments. The material of choice for deepwater oil & gas, seawater injection and FGD systems.
Yield Strength
≥ 550 MPa
Tensile Strength
800 – 1000 MPa
PREN
> 40
Charpy at –46°C
≥ 41 J
ASTM A182 F53
ASTM A276
NORSOK M-630
ISO 15156-3
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High-performance nickel-base alloys for the most extreme environments — elevated temperatures, aggressive chemicals, and high-pressure applications.
Premium Grade · Inconel · Incoloy · Monel · Nickel 200
High-Temp
Inconel · Grades 600 / 625 / 718 / X-750
Inconel
Nickel-chromium superalloy with exceptional strength retention at elevated temperatures up to 980°C. Standard for gas turbines, aerospace, and nuclear reactor components.
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Marine Grade
Monel · Grades 400 / K500
Monel
Copper-nickel alloy combining high strength with excellent resistance to seawater, hydrofluoric acid and alkaline media. Grade K500 adds age-hardening capability.
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Heat Resistant
Incoloy · Grades 800 / 800H / 825 / DS
Incoloy
Iron-nickel-chromium alloys with superior high-temperature oxidation resistance and strength. Used in heat exchangers, furnace equipment and chemical processing.
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High Purity
Nickel · Grades 200 / 201 / 270
Nickel 200 / 201
Commercially pure nickel with excellent resistance to caustic alkalis, reducing environments and salt solutions. Grade 201 for applications above 315°C.
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Chemical Resistant
Hastelloy · Grades C-276 / C-22 / B-2 / B-3
Hastelloy
Outstanding resistance to oxidizing and reducing acids, chlorides and mixed corrosive media. The premier alloy for FGD, pharmaceutical and chemical reactor applications.
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6Mo Alloy
SMO 254 · UNS S31254 · 1.4547
SMO 254 (6Mo)
Super-austenitic stainless with 6% molybdenum offering extreme pitting resistance (PREN ~43) for seawater, bleach and high-chloride process applications.
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Lightweight, exceptionally strong and corrosion-resistant titanium fasteners for aerospace, marine, medical and chemical process applications.
Exotic Alloy · Aerospace Grade
Aerospace Grade
Grade 2 · Grade 5 · Grade 7
Titanium · UNS R50400 / R56400 / R52400
Titanium (Grade 2 & Grade 5)
Grade 2 (commercially pure) offers excellent corrosion resistance to oxidising media at low weight. Grade 5 (Ti-6Al-4V) provides the highest strength-to-weight ratio of any structural metal — the alloy of choice in aerospace, motorsport, deep-sea, and orthopaedic implant fastening.
Density
4.5 g/cm³ (57% of steel)
Tensile (Gr.5)
900 – 1100 MPa
Temp Range
–250°C to +315°C
Corrosion Resistance
Excellent (seawater)
ASTM B348
AMS 4928
ISO 5832-3
MIL-T-9046
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Electrically conductive, non-sparking, and aesthetically attractive non-ferrous fasteners for electrical, plumbing, marine, and decorative applications.
Non-Ferrous · 200+ SKUs
Most Popular
Brass · C360 / C385 / CuZn39Pb3
Brass Fasteners
Free-machining brass offering excellent electrical conductivity, corrosion resistance and antimicrobial properties. Standard for electrical panels, plumbing, valves and decorative hardware.
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Conductive
Copper · C110 / C122 / ETP / DHP
Copper Fasteners
Electrolytic tough pitch (ETP) and deoxidised high phosphorus (DHP) copper fasteners for electrical grounding, transformer connections and heat exchangers.
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Marine Grade
Cupro-Nickel · 90/10 · 70/30 · C70600
Cupro-Nickel
Copper-nickel alloys with outstanding resistance to seawater corrosion and biofouling. Used extensively in marine pipework, heat exchangers and offshore hardware.
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High-strength carbon and alloy steel fasteners in property classes 4.6 through 12.9 — the backbone of structural engineering and heavy industrial applications worldwide.
Standard Grade · 2,000+ SKUs
Standard Grade
Class 4.6 / 8.8 / 10.9 · ASTM A307 / A325
Carbon Steel
Low and medium carbon steel in property classes 4.6, 8.8, 10.9 and 12.9. The most cost-effective choice for general structural and mechanical fastening applications.
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High Strength
B7 / L7 · 4140 / 4340 · Gr.5 / Gr.8
Alloy Steel (B7 / 4140)
Chromium-molybdenum alloy steel for high-strength bolting — ASTM A193 B7 is the industry standard for pressure vessel and pipeline flanged joints.
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Cryogenic
B7M / L7M · 3.5% Nickel Steel · ASTM A320
Low-Temperature Alloy Steel
Modified alloy steels with controlled hardness (B7M/L7M) for sour gas service, and nickel steels for cryogenic LNG, CO₂ and liquid oxygen applications.
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Material Comparison
Properties Comparison Table
Side-by-side mechanical and corrosion properties to help you select the right material for your application.
| Material | Grades | Tensile Strength | Max Temp | Corrosion Resist. | Strength-to-Weight | Typical Use |
|---|---|---|---|---|---|---|
| SS 304 / 316 | A193 B8M | 515–760 MPa | 800°C | General, food, marine | ||
| Duplex 2205 | A182 F51 | 620–880 MPa | 300°C | Oil & gas, chemical | ||
| Super Duplex 2507 | A182 F53 | 800–1000 MPa | 300°C | Offshore, seawater | ||
| Inconel 625 | B637 / B574 | 830–1000 MPa | 980°C | Aerospace, turbines | ||
| Hastelloy C276 | B574 | 690–900 MPa | 1040°C | FGD, pharma, acid | ||
| Monel 400 | B164 | 480–760 MPa | 480°C | Marine, HF acid | ||
| Titanium Gr.5 | B348 / AMS 4928 | 900–1100 MPa | 315°C | Aerospace, medical | ||
| Alloy Steel B7 | A193 B7 | 860–1000 MPa | 450°C | Pressure vessels, pipelines |
Selection Guide
Choosing the Right Material
for Your Application
Match your environment to the optimal alloy — our technical team can advise on the most cost-effective and code-compliant material for every project.
Oil, Gas & Petrochemical
High-pressure, high-temperature flanged systems, sour service (H₂S), NACE compliant bolting and subsea equipment.
A193 B7 / B7M
Duplex 2205
Super Duplex 2507
Inconel 625
Marine & Offshore
Seawater immersion, splash zone, and atmospheric marine environments requiring biofouling and crevice corrosion resistance.
SS 316L
Duplex 2205
Super Duplex 2507
Monel 400
Cupro-Nickel
Power Generation
High-temperature steam service, superheater tubes, turbine components, and nuclear plant bolting.
A193 B7 / B16
Inconel 718
Incoloy 800H
SS 321
Chemical & Pharmaceutical
Acids, alkalis, solvents, bleach, and mixed corrosive media in reactors, vessels, and pharmaceutical clean rooms.
Hastelloy C276
SS 904L
SMO 254
Nickel 200
Food & Beverage
Hygienic, Ra-finished fasteners meeting FDA and cGMP requirements for food contact, CIP cleaning and autoclave sterilisation.
SS 316L (RA finished)
SS 304
Duplex (dairy)
Aerospace & Defence
Lightweight, high-strength fasteners for airframes, engine components and defence equipment requiring tight material traceability.
Titanium Gr.5
Inconel 718
A286 (15-5PH)
MP35N
Technical Data
Temperature & Corrosion Reference
Key technical data to support material selection for your project environment.
Maximum Service Temperature
Corrosion Resistance Matrix
| Material | Seawater | H₂SO₄ | HCl | Caustic |
|---|---|---|---|---|
| SS 316L | Good | Fair | Poor | Good |
| Duplex 2205 | Excellent | Good | Fair | Good |
| Super Duplex | Excellent | Excellent | Good | Excellent |
| Hastelloy C276 | Excellent | Excellent | Excellent | Excellent |
| Inconel 625 | Excellent | Excellent | Good | Excellent |
| Monel 400 | Excellent | Good | Excellent | Good |
| Nickel 200 | Good | Fair | Fair | Excellent |
| Titanium Gr.2 | Excellent | Good | Fair | Good |
ISO 9001:2015
EN 10204 3.1 / 3.2
NABL Lab
PMI Tested
Material Testing
Every Heat Lot
Verified & Documented
Our in-house testing laboratory and NABL-accredited third-party partners verify chemical composition, mechanical properties and dimensional conformance for every material heat lot we process.
PMI Testing — Positive Material Identification
XRF Spectroscopy — ASTM A751 / ASTM E1476
Tensile & Yield Strength Testing
Universal Testing Machine — ASTM F606 / ISO 898
Hardness Testing
Vickers / Rockwell / Brinell — ASTM E18 / ISO 6508
Ultrasonic & MT / PT Testing
UT for internal defects · MT/PT for surface flaws — ASTM E317
Chemical Composition Analysis (OES)
Optical Emission Spectrometry — ASTM A751 / ASTM E415
Global Material Export
All Alloy Grades Exported Worldwide
SM Fastners ships certified fasteners in all material grades to 40+ countries with complete documentation including MTC, COC, PMI reports, and EN 10204 3.1 / 3.2 mill certificates.
🇺🇸 USA
🇬🇧 UK
🇩🇪 Germany
🇦🇺 Australia
🇦🇪 UAE
🇸🇦 Saudi Arabia
🇳🇱 Netherlands
🇸🇬 Singapore
🇧🇷 Brazil
+ 30 more
Not Sure Which Grade?
Our Metallurgists
Will Recommend the Right Alloy
Share your operating conditions — temperature, pressure, media, environment and standards — and our technical team will recommend the optimal material grade and fastener specification.