Stainless Steel Bolt Manufacturers in India
Unifit Fastener is a leading manufacturer and supplier of high-quality industrial fasteners, which deliver quality services in challenging conditions. The company has a wide variety of stainless steel fasteners in high grade, including 304/304H/304L, 310/310S, 316/316L, 317/317L, 321, and 347/347H, which are highly resistant to corrosion, heat, and mechanical stress. These grades render the products of Unifit as suitable in the industries where performance and durability are not a compromise.
Our bolts, nuts, screws, and washers are engineered to be used on long-lasting projects; they are used in marine work, desalination plants, chemical processing units, pumping stations, heavy engineering work, and large infrastructure projects. Their stainless steel rivets are reliable even in settings that are prone to moisture, chemicals, and high temperatures and provide better protection against rust and environmental damage.
The modern manufacturing plant of Unifit Fastener has the capabilities of hot forging, high-tech CNC machining, and an accurate thread-rolling process to make fasteners of high dimensional precision and quality. They have the experience of providing both standard and custom-made fasteners, which have a smooth compatibility with various industrial needs and project specifications.
Unifit Fastener has a solid standing in the world with a presence in the Indian, Middle Eastern, European, and USA markets, as well as a reputation for reliability, consistency, and innovation. Building in the construction industry, automotive, renewable energy, petrochemical plants, or pipeline infrastructure, we provide sustainable high-performance solutions, meeting international quality requirements and contributing to long-term operation.
Request QuoteTable of Contents
- What are Stainless Steel Bolts?
- Specification of Stainless Steel Bolts
- Send Your Enquiry
- Types of Stainless Steel Bolts
- Equivalents of Stainless Steel Bolts
- Chemical Composition of Stainless Steel Bolt
- Mechanical Properties of SS Bolts
- SS Bolt Torque Value Comparison with Non-Ferrous Fasteners
- ISO Standard for Stainless Steel Bolts
- Applications of Stainless Steel Bolts
- FAQs About Stainless Steel Bolts
What are Stainless Steel Bolts?
Stainless steel bolts are high-performance fasteners manufactured from durable stainless steel alloys containing iron, chromium, and varying amounts of nickel and other strengthening elements. This specific blend gives the bolts outstanding protection against rust, corrosion, and temperature fluctuations. Thanks to their superior material properties, stainless steel bolts remain reliable even in challenging or corrosive environments where regular carbon steel bolts are likely to degrade or lose strength.
Stainless Steel Hex Bolts, SS Hex Head Bolts, Stainless Steel Head Bolts, SS Allen Cap Bolts, Stainless Steel Heavy Hex Bolts, Stainless Steel Carriage Bolts, Stainless Steel Anchor Bolts, Stainless Steel Anti-Theft Nuts and Bolts, Stainless Steel Hanger Bolts.
Stainless Steel Bolts Grade
Specification of Stainless Steel Bolts
| Category | Details |
|---|---|
| Specifications | ASTM F593 / ASME SF593 compliant |
| Standards Followed | Manufactured as per DIN, ISO, JIS, GB, IS, BS, ASTM, and other major international standards |
| Available Sizes | M3 to M100 • 3/6″ to 4″ • Customized sizes available upon request |
| Length Range | 3 mm to 200 mm • Custom lengths can be produced |
| Dimensional Standards | DIN 931, 933, 934, 7991, 976, 125, and ASME B18.2.1 / B18.3 |
| Thread Types | METRIC, UNC, UNF, BSW, BSF, or special threads based on requirements |
| Thread Configuration | Unified threads per ASME B1.1 (2A/3A – 2B/3B) and Metric threads per ASME B1.13M (6h–6G) |
| Form Options | Hex, square, round, threaded forms and other shapes as per gauge |
| Head Types | Hex, square, round, flat, hex-flange, T-head, triangular and customized heads |
| Neck Styles | Knurled, square, hex, oval, triangular and other special neck types |
| Surface Finishes | Zinc, Xylan, Teflon, black oxide, cadmium, galvanization, or coatings as specified |
| Manufacturing Process | Wire drawing, cold forming, threading/tapping, heat treatment, coating, inspection, and final packing |
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Types of Stainless Steel Bolts
Hex Bolts
Heavy Hex Bolts
Anchor Bolts
Eye Bolts
Machine Bolt
J Bolts
U Bolts
Square Bolts
Equivalents of Stainless Steel Bolts
| British (BS) | French | German (EN) | Italian | Japanese (SUS) | Swedish | USA (AISI / SS) |
|---|---|---|---|---|---|---|
| 304S21 | Z12CN17.08 | 1.4310 | X12CrNi17-07 | SUS301 | 14 23 31 | 301 |
| 304S31 | – | – | – | SUS302 | 14 23 32 | 302 |
| 304S15 / 304S16 | Z8CN18.09 | 1.4301 | X5CrNi18-10 | SUS304 | 14 23 33 | 304 |
| 304S11 | Z2CN18.10 | 1.4306 | X2CrNi18-11 | SUS304L | 14 23 52 | 304L |
| 305S19 | Z8CN18.12 | – | X8CrNi18-12 | SUS305 | – | 305 |
| 309S24 | Z15CN24.13 | – | X16CrNi23-14 | SUS309 | – | 309 |
| 310S24 | Z12CN25.20 | 1.4845 | Z22CrNi25-20 | SUS310S | 14 23 61 | 310 |
| 315S16 | – | – | – | – | 14 23 40 | – |
| 316S31 / 316S33 | Z6CND17.11 | 1.4401 / 1.4436 | X8CrNiMo17-13 | SUS316 | 14 23 43 / 14 23 47 | 316 |
| 316S11 / 316S13 | Z2CND17.12 | 1.4404 / 1.4435 | X2CrNiMo17-12 | SUS316L | 14 23 53 / 14 23 48 | 316L |
| 317S12 | Z2CND19.15 | 1.4435 | X2CrNiMo18-16 | SUS317L | 14 23 67 | 317L |
| 317S16 | – | 1.4436 | – | SUS317 | 14 23 66 | 317 |
| 320S31 / 320S33 | Z8CND17.12 | 1.4571 / 1.4573 | – | – | 14 23 50 | – |
| 321S31 | Z6CNT18.12 | 1.4541 | X6CrNiTi18-11 | SUS321 | 14 23 37 | 321 |
| 347S31 | Z6CNNb18.11 | 1.4558 | X6CrNiNb18-11 / X8CrNiNb18-11 | SUS347 | 14 23 38 | 347 |
| 403S17 | Z6C13 | 1.4000 | X6Cr13 | SUS403 | 14 23 01 | 403 |
| 405S17 | Z6CA13 | 1.4002 | Z6CrA1-13 | SUS405 | – | 405 |
| 409S19 | – | 1.4512 | – | – | – | 409 |
| 430S17 | Z8C17 | 1.4016 | X8Cr17 | SUS430 | 14 23 20 | 430 |
| 434S17 | Z8CD17.01 | 1.4113 | X8CrMo17 | SUS434 | 14 23 25 | 434 |
| 410S21 | Z12C13 | 1.4006 / 1.4024 | X12Cr13 | SUS410 | 13 23 02 | 410 |
| 410S45 | Z30C13 | – | X30Cr13 | SUS420J | 14 23 04 | 420 |
Chemical Composition of Stainless Steel Bolt
| Grade | AISI | C | Si | Mn | P | S | Cr | Mo | Ni | Cu |
|---|---|---|---|---|---|---|---|---|---|---|
| A1 | SS 202 | 0.12 | 1.0 | 6.5 | 0.20 | 0.15–0.35 | 16.0–19.0 | 0.7 | 5.0–10.0 | 1.75–2.25 |
| A2 | SS 304 | 0.08 | 1.0 | 2.0 | 0.05 | 0.03 | 15.0–20.0 | – | 8.0–19.0 | 4.0 |
| A3 | SS 321 | 0.08 | 1.0 | 2.0 | 0.05 | 0.03 | 17.0–19.0 | – | 9.0–12.0 | 1.0 |
| A4 | SS 316 | 0.08 | 1.0 | 2.0 | 0.05 | 0.03 | 16.0–18.5 | 2.0–3.0 | 10.0–15.0 | 4.0 |
| C1 | SS 410 | 0.09–0.15 | 1.0 | 1.0 | 0.05 | 0.03 | 11.5–14.0 | – | 1.0 | – |
| C3 | SS 431 | 0.17–0.25 | 1.0 | 1.0 | 0.04 | 0.03 | 16.0–18.0 | – | 1.5–2.5 | – |
| C4 | SS 416 | 0.08–0.15 | 1.0 | 1.5 | 0.06 | 0.15–0.35 | 12.0–14.0 | 0.6 | 1.0 | – |
| F1 | SS 430 | 0.12 | 1.0 | 1.0 | 0.04 | 0.03 | 15.0–18.0 | – | 1.0 | – |
Mechanical Properties of SS Bolts
| Bolt Grade | Class | Minimum Tensile Strength (Rm) MPa | Minimum Yield Strength (Rp 0.2) MPa | Minimum Elongation | Applicable Diameter |
|---|---|---|---|---|---|
| A2 / A4 Stainless Steel Bolts | 70 | 700 N/mm² | 450 N/mm² | 0.4d | ≤ M20 |
| A2 / A4 Stainless Steel Bolts | 80 | 800 N/mm² | 600 N/mm² | 0.3d | ≤ M20 |
SS Bolt Torque Value Comparison with Non-Ferrous Fasteners
| Bolt Size | 18-8 Grade (in-lbs) | 316 Grade (in-lbs) | Silicon Bronze (in-lbs) | Monel Alloy (in-lbs) | Brass (in-lbs) | Aluminum 2024-T4 (in-lbs) |
|---|---|---|---|---|---|---|
| 4-40 | 5.2 | 5.5 | 4.8 | 5.3 | 4.3 | 2.9 |
| 4-48 | 6.6 | 6.9 | 6.1 | 6.7 | 5.4 | 3.6 |
| 5-40 | 7.7 | 8.1 | 7.1 | 7.8 | 6.3 | 4.2 |
| 5-44 | 9.4 | 9.8 | 8.7 | 9.6 | 7.7 | 5.1 |
| 6-32 | 9.6 | 10.1 | 8.9 | 9.8 | 7.9 | 5.3 |
| 6-40 | 12.1 | 12.7 | 11.2 | 12.3 | 9.9 | 6.6 |
| 8-32 | 19.8 | 20.7 | 18.4 | 20.2 | 16.2 | 10.8 |
| 8-36 | 22.0 | 23.0 | 20.4 | 22.4 | 18.0 | 12.0 |
| 10-24 | 22.8 | 23.8 | 21.2 | 25.9 | 18.6 | 13.8 |
| 10-32 | 31.7 | 33.1 | 29.3 | 34.9 | 25.9 | 19.2 |
| 1/4-20 | 75.2 | 78.8 | 68.8 | 85.3 | 61.5 | 45.6 |
| 1/4-28 | 94 | 99 | 87 | 106 | 77 | 57 |
| 5/16-18 | 132 | 138 | 123 | 149 | 107 | 80 |
| 5/16-24 | 142 | 147 | 131 | 160 | 116 | 86 |
| 3/8-16 | 236 | 247 | 219 | 266 | 192 | 143 |
| 3/8-24 | 259 | 271 | 240 | 294 | 212 | 157 |
| 7/16-14 | 376 | 393 | 349 | 427 | 317 | 228 |
| 7/16-20 | 400 | 418 | 371 | 451 | 327 | 242 |
| 1/2-13 | 43 | 45 | 40 | 48.7 | 35.2 | 26 |
| 1/2-20 | 45 | 47 | 42 | 51 | 37 | 27 |
| 9/16-12 | 56 | 59 | 53 | 65 | 47 | 34 |
| 9/16-18 | 62 | 65 | 58 | 71 | 51 | 38 |
| 5/8-11 | 92 | 96 | 86 | 111 | 76 | 60 |
| 5/8-18 | 103 | 108 | 96 | 123 | 85 | 67 |
| 3/4-10 | 127 | 131 | 118 | 153 | 104 | 82 |
| 3/4-16 | 124 | 129 | 115 | 149 | 102 | 80 |
| 7/8-9 | 194 | 202 | 178 | 231 | 159 | 124 |
| 7/8-14 | 193 | 201 | 177 | 230 | 158 | 124 |
| 1-8 | 286 | 299 | 265 | 344 | 235 | 184 |
| 1-14 | 259 | 270 | 240 | 311 | 212 | 166 |
ISO Standard for Stainless Steel Bolts
| Product Type | DIN Standard | ISO Standard | ASME / ANSI | Scope |
|---|---|---|---|---|
| HCS (Hex Cap Screws) | 931 | 4014 | B18.2.3.1M | Partially Threaded |
| HCS (Hex Cap Screws) | 933 | 4017 | — | Fully Threaded |
| HCS (Fine Thread) | 960 | 8765 | — | Partially Threaded (Fine) |
| HCS (Fine Thread) | 961 | 8676 | — | Partially Threaded (Fine) |
| Nuts | 934 | 4032 | B18.2.4.1M (Style 1) | Classes 6, 8 & 10 |
| SHCS (Socket Head Cap Screws) | 912 | 4762 | B18.3.1 | — |
| BHSHCS (Button Head Socket Cap Screws) | N/A | 7380 | B18.3.4M | — |
| FHSCS (Flat Head Socket Cap Screws) | N/A | 7991 | B18.3.5 | — |
Applications of Stainless Steel Bolts
Stainless steel bolts are widely used in environments where strength, corrosion resistance, and long service life are essential. Common applications include:
- Marine & Offshore: Shipbuilding, docks, and coastal structures exposed to saltwater.
- Water & Wastewater Systems: Desalination plants, pumping stations, and treatment facilities.
- Industrial Equipment: Pumps, valves, chemical processing units, and machinery.
- Construction & Infrastructure: Bridges, pipelines, and large structural projects.
- Petrochemical Plants: Refineries, reactors, and chemical storage systems.
- Renewable Energy: Wind turbines, solar structures, and utility projects.
FAQs About Stainless Steel Bolts
What are stainless steel bolts used for?
Stainless steel bolts are used in marine, construction, water treatment, petrochemical, and industrial applications where corrosion resistance and durability are required.
Do stainless steel bolts rust?
Stainless steel bolts are highly resistant to rust due to their chromium content. However, slight surface discoloration can occur in extremely harsh or contaminated environments.
Which grades of stainless steel bolts are most common?
Grades like 304, 316, 316L, 321, 310, and 347 are widely used depending on the level of corrosion resistance and mechanical strength required.
Can stainless steel bolts be used in high-temperature applications?
Yes, grades like 310, 321, and 347 are designed for elevated temperature environments