Stainless Steel Bolts Manufacturers in India
Stainless Steel Bolts Supplier India — Krishna Industries
B2B supplier of SS Bolts in all types and grades — SS304 (A2) / SS316 (A4) / Duplex / Nickel Alloy — Hex Head · Carriage · Socket Cap · Socket Thin Head · Socket Low Head · Hex Flange · Hex Lag · T-Bolt — M3 to M20 & 1/8″ to 3/4″ — 6 mm to 200 mm — DIN / ISO / JIS / ASME / ASTM / IS / BSW standards.
MTC on Request · MOQ 10 Nos · GST Invoice (GSTIN: 24AKLPP6499B1ZT) · Pan India Dispatch from Ahmedabad · 2-Hour Quote
As a leading industrial grade stainless steel hex bolts manufacturer Pan India, Krishna Industries (KELOR) supplies the complete range of stainless steel bolts — all head types, all standards, all grades — to EPC contractors, structural fabricators, OEM manufacturers, marine fitout contractors, and industrial buyers across India. A stainless steel bolt (SS bolt) is an externally threaded fastener with a head — used in conjunction with a nut or threaded hole to clamp components together. Unlike a screw, a bolt is designed to pass through clearance holes in both clamped components and be secured by a nut on the opposite side, providing a removable and re-torquable joint. Stainless steel grades — primarily SS304 (A2) and SS316 (A4) — provide corrosion resistance that carbon steel, zinc-plated, or hot-dipped galvanised bolts cannot match in outdoor, marine, chemical, and coastal environments.
We also supply SS washers, SS threaded rods & stud bolts, stud bolts, and eye bolts from the same stock. GST invoice. MOQ 10 Nos. Pan India dispatch.
Bolt vs Screw — Understanding the Distinction
The terms “bolt” and “screw” are used interchangeably in India but have a technically important distinction that affects correct specification:
| Feature | Bolt | Screw |
|---|---|---|
| Installation | Passes through clearance holes in both components — nut provides clamping on the opposite side | Threads directly into a tapped hole, material, or substrate — no nut needed |
| Thread engagement | Full thread engagement via nut — more predictable preload and clamping force | Thread in substrate — engagement depth depends on material thickness and hardness |
| Removal | Remove nut to disassemble — bolt reusable indefinitely | Repeated removal may damage threads in substrate |
| Load bearing | Higher — bolt + nut combination has defined, engineered joint preload per torque table | Lower — thread in substrate can strip; not suitable for high-load structural joints |
| Standards | DIN 931 (partial thread), DIN 933 (full thread), ASME B18.2.1 | DIN 912 (socket cap), DIN 7982 (self-tapping), ASME B18.3 |
| Key Note | All items on this page are bolts — they all require nuts for assembly | See our SS Screws page for self-tapping, socket, and machine screws |
DIN 931 vs DIN 933 — Partial vs Full Thread
The single most commonly confused specification in hex bolt procurement in India. Wrong specification results in bolts that either don’t fit the joint geometry or don’t provide the required grip length.
| Feature | DIN 931 (Partially Threaded) | DIN 933 (Fully Threaded) |
|---|---|---|
| Thread Coverage | Threaded for approximately 2× diameter from the tip — plain (unthreaded) shank under the head | Threaded full length from tip to head bearing face |
| Plain Shank | ✅ Present — shank diameter equals bolt nominal diameter | ❌ No plain shank — fully threaded end to end |
| Grip Length | Plain shank provides defined grip length — critical for shear load applications where the shank (not thread) carries shear | Thread runs through the full joint — no defined shear plane in plain shank |
| Structural Joints | ✅ Preferred — plain shank in shear plane is the correct structural bolt design per IS 800, AISC | ⚠️ Thread in shear plane — weaker in shear; not preferred for structural connections |
| Adjustability | Limited — nut position constrained by thread length | ✅ Nut can be positioned anywhere along the full length — ideal for adjustable connections and varying grip lengths |
| Availability | Available from M8 onwards — short lengths not possible | Available from M3 — full range of short lengths including M3×6 to M3×30 |
| Specify For | Structural steel connections, machinery bolting, pipe flange assembly (where grip length must be controlled), standard M8 and above general industrial use | All small bolt sizes (M3–M6), adjustable connections, channel-frame assembly, general non-structural use where full-length threading is an advantage |
Types of Stainless Steel Bolts — When to Specify
Hex Head Bolt (Hex Bolt)
Most Common · DIN 931 / DIN 933- Six-sided hexagonal head — tightened with standard open-end spanner, ring spanner, or socket
- The universal general-purpose industrial bolt type
- DIN 931: partially threaded (grip shank + threaded end)
- DIN 933: fully threaded from head to tip
- Available M3 to M20 in SS304 (A2) and SS316 (A4)
- Specify for: structural connections, pipe flanges (non-ASME), machinery, general industrial assembly
Carriage Bolt (Round Head Square Neck)
Tamper-Resistant Timber · DIN 603- Domed round head — no drive recess; cannot be tightened from bolt head side
- Square neck locks into square hole in timber or thin metal — prevents rotation
- Provides tamper resistance — nut side only access
- SS316 preferred for outdoor and decking applications
- Specify for: timber decking to steel frame, outdoor furniture, playground equipment, marine timber structures
Socket Cap Screw / Bolt
High Strength · DIN 912 / ISO 4762- Cylindrical head with internal hexagonal (Allen key) socket drive — high torque, compact profile
- Higher tensile strength than standard hex bolts of same nominal size
- Standard for machine guards, process equipment, jigs and fixtures
- Available M3 to M20 in SS304 (A2-70) and SS316 (A4-80)
- Specify for: precision assemblies, machine guards, process equipment panels, pump casings
Socket Thin Head Bolt
Space-Saving · DIN 7984- Reduced head height (~60% of standard DIN 912)
- Lower profile for restricted vertical clearance
- Specify for: electronics housings, thin panel assemblies, sealed equipment enclosures
Socket Low Head Bolt
Ultra Low Profile · DIN 6912- Head height ~40% of standard DIN 912 with larger diameter drive
- Specify for: precision machinery, electronic enclosures, medical equipment
Hex Flange Bolt (Hex Washer Head)
No Separate Washer · DIN 6921- Integral circular flange under head — eliminates need for separate washer
- Serrated variant resists loosening under vibration
- Specify for: automotive, sheet metal, HVAC, thin-wall sections
Hex Lag Bolt (Lag Screw)
Heavy Timber · DIN 571- Large hex head with coarse wood-screw thread — threads directly into timber, no nut needed
- SS316 required for outdoor and treated timber
- Specify for: heavy timber connections, decking, marine timber structures
T-Bolt (Hammer Head Bolt)
Channel Frame · DIN 787- T-shaped head inserts into strut channel slot — locks when nut tightened
- Infinite adjustment along channel — no precise hole drilling needed
- SS316 for outdoor, coastal solar, marine installations
- Specify for: Unistrut pipe supports, cable tray, HVAC suspension, solar panel mounting
SS Grade Selection Guide — SS304 vs SS316 vs Duplex
| Grade | Designation | Key Property | ✅ Specify For | ❌ Not For |
|---|---|---|---|---|
| SS304 (A2) | AISI 304 / DIN 1.4301 / UNS S30400 | 18% Cr + 8% Ni — general corrosion resistance | Indoor machinery, HVAC, food non-GMP, general engineering — most economical SS grade | Marine, coastal, seawater, ACQ treated timber, chemical with chlorides |
| SS316 (A4) | AISI 316 / DIN 1.4401 / UNS S31600 | 18% Cr + 10% Ni + 2–3% Mo — chloride pitting resistance | Marine, coastal, offshore, seawater, chemical plant, ACQ treated timber, food GMP, pharma cleanroom | Budget indoor — 20–30% premium over SS304 |
| SS316L | AISI 316L / DIN 1.4404 / UNS S31603 | Low carbon — improved weld zone corrosion resistance | Welded SS assemblies in corrosive service — pharma, food GMP, chemical process | Non-welded standard bolting — specify 316 unless welded |
| Duplex 2205 | UNS S32205 / DIN 1.4462 | Dual-phase high strength + chloride pitting resistance | Offshore structural, desalination, seawater infrastructure | Standard industrial — over-specified for typical use |
| Nickel Alloy | Monel 400 / Alloy 600 / 625 | Extreme corrosion — seawater, acids, alkalis | Seawater submerged, chemical acid flanges, offshore splash zone | Standard construction — specify only where SS316 inadequate |
Property Class Guide — A2-70, A4-80, A4-100
ISO 3506 property classes define both the material and mechanical strength of the bolt. Always specify both material grade AND property class.
| Property Class | Material | Min. Tensile (MPa) | Min. Yield (MPa) | Specify For |
|---|---|---|---|---|
| A2-70 | SS304 | 700 | 450 | Standard general-purpose SS304 bolting |
| A2-80 | SS304 (work-hardened) | 800 | 600 | Higher-load SS304 structural connections |
| A4-70 | SS316 | 700 | 450 | Standard SS316 in corrosive environments |
| A4-80 | SS316 | 800 | 600 | High-strength SS316 — marine, chemical, food GMP |
| A4-100 | SS316 (work-hardened) | 1000 | 800 | High-load offshore, structural, chemical plant |
SS Hex Bolt Dimensions — DIN 933 Fully Threaded
Reference dimensions for SS304 and SS316 hex bolts per DIN 933 / ISO 4017.
| Thread | Pitch (mm) | Width Flats — s (mm) | Head Height — k (mm) | Standard Lengths (mm) |
|---|---|---|---|---|
| M3 | 0.50 | 5.5 | 2.0 | 6, 8, 10, 12, 16, 20, 25, 30 |
| M4 | 0.70 | 7.0 | 2.8 | 8, 10, 12, 16, 20, 25, 30, 35, 40 |
| M5 | 0.80 | 8.0 | 3.5 | 10, 12, 16, 20, 25, 30, 35, 40, 50 |
| M6 | 1.00 | 10.0 | 4.0 | 10, 12, 16, 20, 25, 30, 35, 40, 50, 60 |
| M8 | 1.25 | 13.0 | 5.3 | 16, 20, 25, 30, 35, 40, 50, 60, 70, 80 |
| M10 | 1.50 | 17.0 | 6.4 | 20, 25, 30, 35, 40, 50, 60, 70, 80, 100 |
| M12 | 1.75 | 19.0 | 7.5 | 25, 30, 35, 40, 50, 60, 70, 80, 100, 120 |
| M14 | 2.00 | 22.0 | 8.8 | 30, 35, 40, 50, 60, 70, 80, 100, 120 |
| M16 | 2.00 | 24.0 | 10.0 | 30, 35, 40, 50, 60, 70, 80, 100, 120, 150 |
| M18 | 2.50 | 27.0 | 11.5 | 40, 50, 60, 70, 80, 100, 120, 150 |
| M20 | 2.50 | 30.0 | 12.5 | 40, 50, 60, 70, 80, 100, 120, 150, 200 |
SS Bolt Tightening Torque — A2-70 & A4-80 Values
Indicative dry (unlubricated) tightening torque values. Anti-seize lubricant reduces required torque by approximately 25–30% and is strongly recommended to prevent galling in SS-on-SS assemblies.
| Thread | A2-70 Torque (Nm) — Dry | A4-80 Torque (Nm) — Dry | With Anti-Seize (approx.) |
|---|---|---|---|
| M4 | 1.5–2.0 | 2.0–2.5 | 1.2–1.7 |
| M5 | 3.0–4.0 | 4.0–5.0 | 2.5–3.5 |
| M6 | 5.0–7.0 | 7.0–9.0 | 4.0–6.0 |
| M8 | 12–16 | 16–20 | 10–14 |
| M10 | 25–32 | 32–40 | 20–28 |
| M12 | 42–54 | 55–70 | 35–48 |
| M14 | 68–86 | 88–112 | 56–76 |
| M16 | 100–130 | 132–168 | 84–115 |
| M20 | 200–250 | 260–330 | 170–220 |
Standards Available for SS Bolts
As a premier ASTM / DIN / IS standard stainless steel bolts distributor India, we maintain strict compliance with global and national fastener specifications to ensure maximum safety and reliability for your projects.
| Standard | Bolt Types Covered | Key Application |
|---|---|---|
| DIN 933 | Hex bolt fully threaded | Most common general-purpose hex bolt in India |
| DIN 931 | Hex bolt partially threaded | Structural and machinery bolting where grip length required |
| DIN 912 / ISO 4762 | Socket cap bolt | Machine guards, process equipment, precision assemblies |
| DIN 7984 | Socket thin head bolt | Space-restricted assemblies |
| DIN 6912 | Socket low head bolt | Ultra-low-clearance assemblies |
| DIN 6921 | Hex flange bolt | Sheet metal, automotive, HVAC without separate washer |
| DIN 603 | Carriage bolt | Timber structures, outdoor furniture, tamper-resistant joints |
| DIN 571 | Hex lag bolt (lag screw) | Heavy timber structural connections |
| DIN 787 | T-bolt (hammer head) | Channel frame / Unistrut assembly |
| ASME B18.2.1 | Hex bolts (US) | US-standard EPC and export projects — inch sizes |
| IS 1367 | General fasteners | Indian standard for government / PSU procurement |
Applications — Where SS Bolts Are Specified
Structural & Civil
SS316 hex bolts for outdoor structural steel connections, coastal bridges, jetty structures.
Decking & Timber
SS316 carriage bolts and lag bolts for heavy timber decking, pergola frames.
Marine & Offshore
SS316 hex and socket bolts for marine vessel fittings, offshore platform connections.
Industrial Equipment
SS304/SS316 socket cap and hex bolts for machine guards, process equipment panels.
Solar & Renewables
SS316 T-bolts and hex flange bolts for solar panel mounting channel frames.
Food & Pharma
SS316 socket cap bolts for food processing, dairy plant, pharma cleanroom assemblies.
Chemical Plant
SS316/Duplex hex bolts for piping support, equipment skids, platform grating.
Custom & OEM
Custom lengths, non-standard grades, anti-galling coatings for OEM projects.
How to Order SS Bolts from KELOR
1. Bolt type — Hex / Carriage / Socket Cap / Socket Thin / Socket Low / Hex Flange / Lag / T-Bolt
2. Thread standard — DIN 933 (full) / DIN 931 (partial) / ASME B18.2.1
3. Material grade — SS304 / SS316 / SS316L / Duplex
4. Property class — A2-70 / A4-80 / A4-100
5. Diameter — M3 to M20 (or imperial 1/8″–3/4″)
6. Length (mm or inches)
7. Quantity (Nos)
8. Nut & washer required? Yes / No
9. MTC required? Yes / No
10. Delivery location (for freight calculation)
📱 WhatsApp: +91 93135 43530 | 📧 Email: sales@kelorvalves.com
Request our stainless steel bolts wholesale price list India wide for immediate bulk pricing and freight estimates.
Why Buy SS Bolts from Krishna Industries?
B2B Industrial Supplier
We are a trusted bulk SS 316 / SS 304 bolts supplier for EPC contractors, structural fabricators, OEMs, and MRO stores. GST invoice on every order.
MTC & Test Certificates
Mill Test Certificate available on request for all SS bolt orders. Grade and standard conformance documented.
2-Hour Quote
WhatsApp complete specification — price, availability, and delivery confirmed within 2 business hours.
Pan India Dispatch
Dispatch from Ahmedabad via VRL Logistics, DTDC, and Professional Courier to all major industrial cities.
Complete Fastener Range
One-stop supplier for bolts, washers, threaded rods, stud bolts, eye bolts, and industrial valves.
ISO Certified Quality
We are a custom heavy-duty stainless steel bolts supplier with ISO certification, guaranteeing premium quality and strict adherence to global standards.
Related Products from Krishna Industries
Get a Quote for SS Bolts — 2-Hour Response
Hex · Carriage · Socket Cap · Hex Flange · Lag · T-Bolt · SS304 · SS316 · Duplex · M3–M20 · DIN ISO ASTM IS · A2-70 A4-80 · GST Invoice · Pan India Dispatch
Quick Specification Summary
| Parameter | Details |
|---|---|
| Product | Stainless Steel Bolts — all types |
| Bolt Types | Hex Head (DIN 933/931) · Carriage · Socket Cap · Socket Thin · Socket Low · Hex Flange · Hex Lag · T-Bolt |
| Materials | SS304 (A2), SS316 (A4), SS316L, Duplex 2205, Nickel Alloy |
| Thread Range | M3 to M20 (metric) · 1/8″ to 3/4″ (imperial) |
| Length Range | 6 mm to 200 mm |
| Property Classes | A2-70, A2-80, A4-70, A4-80, A4-100 per ISO 3506 |
| Standards | DIN 933/931/912/7984/6912/6921/603/571/787, ISO 4017/4014/4762, ASME B18.2.1, IS 1367 |
| MOQ | 10 Nos per type per grade per size |
| HSN Code | 73181590 |
| GST Rate | 18% |
| MTC | Available on request |
| Dispatch | Ahmedabad — Pan India via VRL Logistics, DTDC, Professional Courier |
| GSTIN | 24AKLPP6499B1ZT |
People Also Ask — Stainless Steel Bolts
SS304 (A2) bolts contain 18% chromium and 8% nickel, offering good general corrosion resistance for indoor environments. SS316 (A4) bolts add 2-3% molybdenum, significantly increasing resistance to chloride pitting and crevice corrosion. Specify SS316 for marine, coastal, seawater, chemical plant, and pharmaceutical environments.
A reliable supplier should provide Mill Test Certificates (MTC) as per EN 10204 3.1 or 3.2, ISO 9001:2015 certification, and material test reports verifying chemical composition and mechanical properties against ASTM, DIN, or IS standards.
The standard MOQ is 10 Nos per type, grade, and size for stock items. For non-standard bolt types, special grades (Duplex, Nickel Alloy), or custom lengths, the MOQ may be higher, with a typical lead time of 2-4 weeks.
For highly corrosive environments, SS316 (A4-80) or Duplex 2205 is recommended due to molybdenum content. For extreme high-temperature applications, specialized grades like Alloy 600/625 or A4-100 work-hardened stainless steel are specified.
Weight can be calculated using the formula: (π × d² / 4) × length × density (0.00793 kg/cm³ for SS304/SS316). For accurate bulk freight and pricing, request our stainless steel bolts wholesale price list India wide, which includes weight per 1000 pieces.
DIN 933/ISO 4017 specifies product grade C for general tolerances and grade A for precise tolerances. IS 1367 aligns with these, defining strict limits on head height, width across flats, and thread pitch to ensure proper nut engagement.
Yes, as a bulk SS 316 / SS 304 bolts supplier for EPC contractors, we provide Metric (ISO), UNC, and UNF thread types. We are also a custom heavy-duty stainless steel bolts supplier with ISO certification, ensuring we meet exact project specifications.
Standard stock items are dispatched within 24-48 hours. Custom or non-standard stainless steel bolts typically require a manufacturing lead time of 2 to 4 weeks, depending on the complexity, grade, and order volume.
While galvanized carbon steel bolts have a lower initial cost, stainless steel bolts offer a significantly lower lifecycle cost for plant maintenance due to their superior corrosion resistance, eliminating the need for frequent replacements in harsh environments.
Yes, as an industrial grade stainless steel hex bolts manufacturer Pan India, we provide reliable pan-India logistics and can arrange Just-In-Time (JIT) delivery schedules for large-scale EPC and industrial projects directly from our Ahmedabad facility.