Stainless Steel
Fasteners
Precision-Engineered. Corrosion-Resistant. Export-Ready.
HITECH Fastener manufactures high-precision stainless steel fasteners conforming to international standards—ASTM, DIN, ISO, and ASME—for critical applications across oil & gas, marine, petrochemical, and infrastructure sectors worldwide.
What Are Stainless Steel Fasteners?
Stainless steel fasteners are threaded and non-threaded fastening elements manufactured from iron-chromium alloys containing a minimum of 10.5% chromium by weight. The chromium content creates a self-repairing passive oxide layer on the surface, granting exceptional resistance to corrosion, oxidation, and chemical attack — without any surface coating.
These fasteners are the preferred choice across demanding industries where longevity, hygiene, aesthetics, and high-temperature performance are non-negotiable. They are manufactured as bolts, nuts, studs, screws, washers, threaded rods, and custom components across a range of stainless steel grades from austenitic (304, 316) to duplex and super duplex variants.
At HITECH Fastener, each stainless steel fastener is manufactured from certified raw materials, machined with CNC precision, and inspected with full traceability. Our products are supplied to global buyers in the USA, UK, Germany, UAE, and Southeast Asia with complete test certificates.
Key Advantages
- Excellent corrosion resistance in saline & chemical environments
- High temperature and creep strength
- Hygienic — meets food grade & pharma requirements
- Non-magnetic options available (Austenitic grades)
- No post-fabrication surface treatment required
- Long service life with low maintenance cost
Stainless Steel Grades We Supply
All grades are sourced from mill-certified raw material and supplied with EN10204 3.1 or 3.2 test certificates on request.
SS 304 / 304L
Most widely used austenitic grade
SS 316 / 316L
Marine-grade, Mo-enhanced corrosion resistance
SS 202
Mn-substituted, cost-effective alternative
Duplex 2205
Austenitic-Ferritic dual phase microstructure
Super Duplex 2507
Extreme corrosion resistance, high strength
SS 410 / 416
Martensitic — hardenable, magnetic
International Standards Followed
Chemical Composition Table
All values in weight percentage (%). Data sourced from ASTM/EN material datasheets.
| Grade | C % Max | Mn % Max | Si % Max | Cr % | Ni % | Mo % | N % Max | P % Max | S % Max |
|---|---|---|---|---|---|---|---|---|---|
| SS 304 | 0.08 | 2.00 | 0.75 | 18.0–20.0 | 8.0–10.5 | — | 0.10 | 0.045 | 0.030 |
| SS 304L | 0.03 | 2.00 | 0.75 | 18.0–20.0 | 8.0–12.0 | — | 0.10 | 0.045 | 0.030 |
| SS 316 | 0.08 | 2.00 | 0.75 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | 0.10 | 0.045 | 0.030 |
| SS 316L | 0.03 | 2.00 | 0.75 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | 0.10 | 0.045 | 0.030 |
| SS 202 | 0.15 | 7.5–10.0 | 0.75 | 17.0–19.0 | 4.0–6.0 | — | 0.25 | 0.06 | 0.030 |
| Duplex 2205 | 0.03 | 2.00 | 1.00 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.14–0.20 | 0.030 | 0.020 |
| S. Duplex 2507 | 0.03 | 1.20 | 0.80 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 0.24–0.32 | 0.035 | 0.020 |
| SS 410 | 0.15 | 1.00 | 1.00 | 11.5–13.5 | — | — | — | 0.040 | 0.030 |
Mechanical Properties by Grade
| Grade | 0.2% Yield Strength (MPa) | Tensile Strength (MPa) | Elongation % (min) | Hardness (HRB max) | PREN |
|---|---|---|---|---|---|
| SS 304 | 205 | 515 | 40 | 92 | 18–20 |
| SS 304L | 170 | 485 | 40 | 92 | 18–20 |
| SS 316 | 205 | 515 | 40 | 95 | 24–26 |
| SS 316L | 170 | 485 | 40 | 95 | 24–26 |
| SS 202 | 260 | 515 | 40 | 92 | 17–19 |
| Duplex 2205 | 450 | 620 | 25 | 31 HRC | 35–38 |
| S. Duplex 2507 | 550 | 795 | 15 | 32 HRC | 42–45 |
| SS 410 (Ann.) | 207 | 480 | 20 | 96 | 11–13 |
Heat Treatment Processes
Annealing (Solution Annealing)
1010°C – 1120°C | Water QuenchApplied to austenitic grades (304, 316) after cold working or welding. Dissolves carbide precipitates, restores corrosion resistance, and eliminates work-hardening. Followed by rapid water quenching to prevent re-sensitization. Standard requirement per ASTM A193.
Quenching
Oil / Water / Air QuenchUsed primarily for martensitic grades (410, 416). Rapid cooling from austenitizing temperature (980–1010°C) transforms microstructure to martensite, significantly increasing hardness and tensile strength. Quench media selection depends on section thickness and grade.
Tempering
150°C – 370°C | Air CoolFollows quenching for martensitic grades to reduce brittleness while retaining hardness. Tempering at 150–260°C provides maximum hardness; tempering at 300–370°C improves toughness. Not recommended in the 425–600°C range due to temper embrittlement risk.
Manufacturing Process
Each fastener is manufactured through a controlled sequence of operations to ensure dimensional accuracy and metallurgical integrity.
Forging
Hot or cold forging of certified SS bar stock. Closed-die forging for complex geometries. Ensures grain refinement and consistent mechanical properties throughout the cross-section.
CNC Machining
High-precision CNC turning and milling for dimensional accuracy to ±0.01mm. Full dimensional verification per ASME B18 tolerances. Custom lengths and profiles available.
Thread Rolling
Cold thread rolling produces superior thread strength (+30% vs cut threads), burnished surface finish, and closer tolerances. Available in Class 2A, 3A (UNC/UNF) and 6g (metric).
Heat Treatment
Solution annealing in controlled atmosphere furnaces. Precise temperature and cycle time control. Full traceability of furnace records provided on request with test reports.
Surface Finishing
Electro-polishing, passivation per ASTM A967, mechanical polishing, or customer-specified finishes. Final passivation ensures restoration of passive chromium oxide layer.
Available Surface Finishes
Black Oxide
Provides mild corrosion protection for indoor applications. Applied at 135–145°C, creates magnetite layer. Cost-effective for non-critical environments. Typical film thickness: 1–3 µm.
Zinc Plated (Electroplated)
Provides cathodic protection against corrosion. Applied 5–12 µm thickness. Available clear, yellow, or blue passivated. Complies with ASTM B633. Suitable for mild outdoor exposure.
Hot Dip Galvanized (HDG)
Minimum 45–85 µm zinc coating per ASTM A153. Superior protection for outdoor/buried applications. Suitable for structural bolts and anchor bolts per ASTM F2329.
PTFE / Xylan Coated
Fluoropolymer coating provides anti-galling, low friction, and chemical resistance. Ideal for stainless-to-stainless joints. Applied 15–30 µm. Colors available. Reduces torque by 50%.
Electro-Polished
Electrochemical process removes surface imperfections, improves Ra finish to <0.5 µm. Enhances corrosion resistance, cleanability, and aesthetics. Preferred for pharma and food-grade fasteners.
Mirror / Mechanical Polishing
Hand or machine polished to #4 (Brushed), #6, or #8 (Mirror) finishes per ASTM A480. Common for architectural and decorative applications. Ra value down to 0.1 µm for #8 finish.
Inspection & Testing Methods
Every batch undergoes multi-stage quality checks. Test certificates are provided as per EN 10204 2.1 / 3.1 / 3.2 as applicable.
PMI — Positive Material Identification
Portable XRF/OES analysis confirms alloy composition matches certified grade. 100% PMI available on critical orders. Ensures no material mix-up across batches.
Hardness Testing
Rockwell (HRC/HRB), Brinell (HB), and Vickers (HV) hardness testing performed per ASTM E18, E10, E384. Compliance to max hardness limits per NACE MR0175/ISO 15156 for sour service.
Tensile Testing
Universal Testing Machine (UTM) evaluates UTS, yield strength, and elongation per ASTM A370. Proof load testing per ISO 898-1 for high-strength grades. Full stress-strain curve available.
Ultrasonic Testing (UT)
Phased-array UT detects internal voids, laminations, and inclusions in large-diameter or safety-critical fasteners. Performed per ASTM E317 / EN 10307 on customer request.
Dimensional Inspection
CMM (Coordinate Measuring Machine) and optical comparator verify all critical dimensions: diameter, pitch, thread profile, head height, and surface Ra. Thread gauges: Go/No-Go per ISO 1502.
Corrosion / Salt Spray Test
Neutral salt spray test per ASTM B117 / ISO 9227 confirms corrosion protection of coated fasteners. Intergranular corrosion test per ASTM A262 Practices A/E for sensitization detection.
Industries & Applications
Oil & Gas
Flange bolting for pressure vessels, wellhead equipment, subsea pipelines, and refineries. Grades: A193 B7M, B8M, 2205/2507 Duplex for sour & H₂S environments. NACE compliant.
Marine & Offshore
Superior chloride resistance for ship building, offshore platforms, and desalination plants. SS 316L and Super Duplex 2507 fasteners for submerged and splash-zone applications.
Construction & Infrastructure
Structural bolting, anchor systems, and façade cladding connections. Aesthetic polished finishes for architectural glazing, curtain walls, and landmark structures worldwide.
Petrochemical & Chemical
Heat exchanger bolting, reactor vessels, and pipe flange connections in aggressive chemical environments. High temperature grades for operating temps up to 800°C.
Power Plants
Turbine casings, boiler drum studs, and heat exchanger bolting in thermal, nuclear, and renewable energy plants. Compliance with ASME Boiler & Pressure Vessel Code requirements.
Pharma & Food Processing
Electro-polished, FDA-compliant SS 316L fasteners for hygienic piping systems, reactors, and processing equipment. Smooth surface finish prevents bacterial adhesion.
Export Data & Documentation
Countries We Supply To
Packaging
- Wooden pallets / export-grade crates for large bulk orders
- Polybag + carton box with individual part labelling
- Anti-corrosion VCI paper wrapping for stainless grades
- Fumigation certificates available for wooden packaging
- Marking: Part No., Grade, Lot No., Heat No., Weight
Export Documentation
Technical Comparison Tables
Material Comparison Table
| Property | SS 304 | SS 316 | Duplex 2205 | S. Duplex 2507 | SS 410 |
|---|---|---|---|---|---|
| Corrosion Resistance | Good | Very Good | Excellent | Superior | Moderate |
| Tensile Strength | 515 MPa | 515 MPa | 620 MPa | 795 MPa | 480 MPa |
| Weldability | Excellent | Excellent | Good | Good | Fair |
| Magnetic | No | No | Slightly | Slightly | Yes |
| Chloride Resistance | Fair | Good | Very Good | Excellent | Poor |
| Max Temp (Cont.) | 870°C | 870°C | 300°C | 280°C | 700°C |
| Relative Cost | Low | Medium | High | Very High | Low |
Corrosion Resistance Chart (PREN Values)
PREN = %Cr + 3.3×%Mo + 16×%N — Higher value = Better pitting resistance
Yield Strength Comparison (MPa)
Torque Chart — Stainless Steel Fasteners
Recommended tightening torque values for SS 304 and SS 316 bolts. Values assume clean, dry threads with no lubrication (K ≈ 0.20).
| Bolt Size | Pitch (mm) | Stress Area (mm²) | SS 304 Torque (Nm) | SS 316 Torque (Nm) | Duplex Torque (Nm) | Proof Load (kN) |
|---|---|---|---|---|---|---|
| M6 | 1.0 | 20.1 | 5.5 | 5.8 | 8.2 | 4.1 |
| M8 | 1.25 | 36.6 | 13 | 14 | 20 | 7.5 |
| M10 | 1.5 | 58.0 | 26 | 28 | 40 | 11.9 |
| M12 | 1.75 | 84.3 | 45 | 48 | 70 | 17.3 |
| M16 | 2.0 | 157 | 110 | 117 | 168 | 32.2 |
| M20 | 2.5 | 245 | 215 | 228 | 330 | 50.3 |
| M24 | 3.0 | 353 | 370 | 392 | 567 | 72.4 |
| M30 | 3.5 | 561 | 730 | 775 | 1120 | 115 |
| M36 | 4.0 | 817 | 1260 | 1340 | 1940 | 168 |
| M42 | 4.5 | 1121 | 2100 | 2230 | 3220 | 230 |
Preload Calculation Guide
Understanding preload is critical for safe, reliable bolted joint design. Use these formulas as a starting point before applying project-specific factors.
Variable Definitions
Design Tip: For critical joints (pressure vessels, flanges, subsea), preload scatter can be ±25–30% with standard torque tools. Consider using hydraulic bolt tensioners or direct tension indicators (DTIs) for tighter preload control in ASME PCC-1 applications.
Ready to Source Stainless Steel Fasteners?
Send us your specifications, drawings, or grade requirements. Our technical team will respond within 24 hours with pricing and availability.