Industrial Fastener Solutions
Special
Fastener
Complete range of industrial fasteners — Stud Bolts, Heavy Hex, PTFE Coated, Hot Dip Galvanised, and Threaded Rods — in SS, High Tensile, Carbon Steel, Duplex, and Brass. Compliant with ASTM, ASME, ISO, DIN, EN, and BS standards for global export.
ASTM A193 / A194 ASME B18.2.1 ISO 898 DIN 931 / 976 EN 14399 BS 4882
Fastener Types — Full Range
All fasteners available with EN 10204 3.1 / 3.2 Mill Test Certificates, hardness reports, PMI for alloy grades, and full dimensional inspection. NACE MR0175 / ISO 15156 compliance on request.
Stud Bolts (B7 / B8 / L7)
ASTM A193 / A194 · ASME B16.5 · ASME B18.2.1 · DIN 976
Fully threaded stud bolts with two heavy hex nuts — the standard fastener for ASME pressure flange joints. Available in imperial and metric thread forms. Thread engagement equal on both ends ensures balanced bolt load.
- TypesFully threaded stud bolt · Tap-end stud · Double-end stud
- Thread FormUNC (Unified Coarse) · UNF (Fine) · 8UN (special for large dia.) · Metric M per ISO 965
- Size Range (imp.)½″ to 4″ diameter
- Size Range (metric)M12 to M100
- LengthPer ASME B16.5 flange bolt chart or custom cut length
- Nuts SuppliedHeavy Hex Nuts per ASME B18.2.2 / ASTM A194
- CS / Alloy GradesASTM A193 B7 / B7M · B16 · L7 / L7M (low temp)
- SS GradesASTM A193 B8 (304) · B8M (316) · B8T (321) · B8C (347) · B8N (347)
- Nut GradesASTM A194 2H (CS) · 2HM · 8 (304) · 8M (316) · 8T / 8C
- Yield StrengthB7: 725 MPa min · B8 (Class 1): 207 MPa · B8 (Class 2): 552 MPa
- Temp. RangeB7: -45°C to +450°C · L7: -100°C · B8M: -196°C to +816°C
- FinishPlain · Black Oxide · Zinc Plated · PTFE Coated · Hot Dip Galvanised
ASTM A193ASTM A194 ASME B18.2.1DIN 976BS 4882
Heavy Hex Bolts & Nuts
ASTM A307 / A325 / A490 · ASME B18.2.1 / B18.2.2 · ISO 4014
Heavy series hex bolts with larger bearing surface and head dimensions than standard hex bolts. Used for structural steel connections, heavy equipment, and flanged joints requiring high clamping force.
- TypesHeavy Hex Bolt (full thread) · Heavy Hex Bolt (partial thread) · Heavy Hex Nut
- Size Range (imp.)½″ to 4″ UNC / UNF
- Size Range (metric)M12 to M100 per ISO 4014 / DIN 931
- CS GradesASTM A307 Gr.A/B · A325 Type 1/3 · A490 · SAE Gr.5 / Gr.8
- HT GradesISO 898-1: Cl.8.8 / 10.9 / 12.9 · EN 14399-3/4 (HR / HV)
- SS GradesA2-70 / A2-80 (SS 304) · A4-70 / A4-80 (SS 316) per ISO 3506
- Nut GradesASTM A194 2H · ISO 4032 Cl.8 / Cl.10 / Cl.12 · DIN 934
- Proof Load (8.8)580 MPa (M16–M72) · Yield: 640 MPa · UTS: 800 MPa
- Proof Load (10.9)830 MPa · Yield: 940 MPa · UTS: 1040 MPa
- Proof Load (12.9)970 MPa · Yield: 1100 MPa · UTS: 1220 MPa
ASTM A307/325/490ISO 898 ASME B18.2.1DIN 931/934EN 14399
ASTM A193 Bolt Grade — A194 Nut Grade Pairing
| Bolt Grade | Material | Matching Nut Grade | Min. Yield (MPa) | Min. UTS (MPa) | Temp. Range | Service |
|---|---|---|---|---|---|---|
| B7 | Cr-Mo Alloy Steel (4140/4142) | A194 2H | 725 | 862 | -45°C to +450°C | General high pressure / high temp |
| B7M | Cr-Mo Alloy (controlled hardness) | A194 2HM | 552 | 724 | -45°C to +450°C | Sour service (NACE MR0175) |
| L7 | Cr-Mo Alloy Steel (low temp) | A194 4 | 725 | 862 | -100°C to +450°C | Low temperature process |
| L7M | Cr-Mo Alloy (low temp, NACE) | A194 4 | 552 | 724 | -100°C to +450°C | Low temp + sour service |
| B16 | Cr-Mo-V Alloy Steel | A194 7 | 724 | 896 | -30°C to +538°C | High temp steam, power plants |
| B8 Cl.1 | SS 304 (annealed) | A194 8 | 207 | 517 | -196°C to +816°C | Low strength, cryogenic compatible |
| B8 Cl.2 | SS 304 (strain hardened) | A194 8 | 552 | 758 | -196°C to +816°C | High strength SS application |
| B8M Cl.1 | SS 316 (annealed) | A194 8M | 207 | 517 | -196°C to +816°C | Corrosive, marine, chemical |
| B8M Cl.2 | SS 316 (strain hardened) | A194 8M | 552 | 758 | -196°C to +816°C | High strength SS 316 service |
| B8T Cl.1/2 | SS 321 (Ti-stabilised) | A194 8T | 207 / 552 | 517 / 758 | -196°C to +816°C | High temp sensitisation-resistant |
| B8C Cl.1/2 | SS 347 (Nb-stabilised) | A194 8C | 207 / 552 | 517 / 758 | -196°C to +816°C | High temp, refinery service |
Hex Bolts
ISO 4014 / 4017 · DIN 931 / 933 · ASME B18.2.1 · EN ISO 4014
Standard external hex drive bolts with partial thread (ISO 4014 / DIN 931) or full thread (ISO 4017 / DIN 933). Most common fastener globally — available in all MOCs and all standard metric and imperial sizes.
- TypesPartial thread (DIN 931) · Full thread (DIN 933) · Hex Flange Bolt (DIN 6921)
- Metric Size RangeM4 to M100 (ISO metric)
- Imperial Size Range¼″ to 4″ UNC/UNF (ASME B18.2.1)
- Thread PitchCoarse (standard) · Fine · Extra-fine per ISO 965
- CS / HT GradesISO 898: Cl.4.6 / 4.8 / 5.6 / 5.8 / 6.8 / 8.8 / 10.9 / 12.9
- SS GradesISO 3506: A2-50/70/80 (304) · A4-50/70/80 (316)
- Brass / Cu GradesCu1 / Cu2 / Cu3 per ISO 8839
- Head TypeHex (standard) · Heavy Hex · Hex Flange · Hex Washer Head
- ToleranceProduct Grade A (M1.6–M24, fine) · Grade B (M24+, coarse)
ISO 4014/4017ISO 898 DIN 931/933ASME B18.2.1EN ISO 4014
Hex Nuts & Heavy Hex Nuts
ISO 4032 / 4033 · DIN 934 / 935 · ASME B18.2.2 · ASTM A194
Standard and heavy hex nuts in full range of property classes. Heavy hex nuts have larger across-flats dimension and greater height than standard — mandatory for flange bolting per ASME B16.5.
- TypesHex Nut (DIN 934) · Heavy Hex Nut (ASME B18.2.2) · Hex Lock Nut (DIN 985 / 982) · Jam Nut · Flange Nut (DIN 6923) · Coupling Nut (DIN 6334)
- Metric Size RangeM4 to M100
- Imperial Size Range¼″ to 4″ (ASME B18.2.2)
- Property ClassISO 4032: Cl.5 / 6 / 8 / 10 / 12
- CS / HT GradesASTM A194 2H / 2HM / 4 / 7 · ISO 898-2
- SS GradesASTM A194 8 / 8M / 8T / 8C · ISO 3506 A2 / A4
- Duplex GradesASTM A194 Grade 8 (custom alloy) · UNS S31803 / S32750
- BrassCuZn39Pb3 (CW614N) · CuZn40Pb2 (CW617N) per EN 12164
ISO 4032/4033ASTM A194 DIN 934ASME B18.2.2
Washers (Plain, Spring & Lock)
ISO 7089 / 7090 · DIN 125 / 127 / 9021 · ASME B18.22.1
Plain, spring, and serrated lock washers supplied as part of complete fastener assemblies. Available in all MOCs to match bolt and nut material specification.
- Plain Washer TypesStandard (DIN 125A/B) · Large OD (DIN 9021) · Structural (F436 / F959)
- Spring WasherSplit lock (DIN 127) · Disc spring (Belleville / DIN 6796)
- Serrated WasherInternal (DIN 6797A) · External (DIN 6797J) · Both faces
- Size RangeM4 to M100 metric · ¼″ to 4″ imperial
- MOCCS · SS 304/316 · Duplex · Brass · Cu-Ni · Titanium
- Hardness (F436)38–45 HRC (structural hardened washer)
ISO 7089/7090DIN 125/127ASME B18.22.1
ISO 898-1 Bolt Property Classes — Mechanical Properties
| Property Class | Min. Yield (MPa) | Min. UTS (MPa) | Min. Hardness | Max. Hardness | Typical Material | Common Use |
|---|---|---|---|---|---|---|
| 4.6 | 240 | 400 | 120 HV | 220 HV | Low / medium CS | Light structures, low load applications |
| 4.8 | 340 | 420 | 130 HV | 220 HV | Low / medium CS | General purpose fastening |
| 5.6 | 300 | 500 | 155 HV | 220 HV | Medium CS | Structural, general engineering |
| 5.8 | 420 | 520 | 160 HV | 220 HV | Low/medium CS | Machine building |
| 6.8 | 480 | 600 | 190 HV | 250 HV | Medium CS | General purpose higher load |
| 8.8 | 640 | 800 | 245 HV | 335 HV | Alloy or medium CS (Q&T) | Structural steel (EN 14399-3), piping, machinery |
| 10.9 | 940 | 1040 | 320 HV | 380 HV | Alloy steel (Q&T) | High-strength structural, heavy equipment |
| 12.9 | 1100 | 1220 | 385 HV | 435 HV | Alloy steel (Q&T) | Highest strength — critical applications |
Q&T = Quenched and Tempered. Property class marking: first digit × 100 = min UTS (MPa); second digit × 10% × min UTS = min yield (MPa). Example: 8.8 → UTS 800 MPa, yield = 0.8 × 800 = 640 MPa.
ISO 3506 — Stainless Steel Fastener Property Classes
| Grade | Steel Group | Common SS | Property Class | Min. UTS (MPa) | Min. Yield (MPa) | Notes |
|---|---|---|---|---|---|---|
| A1 | Austenitic (free machining) | SS 303 | -50 / -70 | 500 / 700 | 210 / 450 | Not for chloride environments |
| A2 | Austenitic (standard) | SS 304 / 304L | -50 / -70 / -80 | 500 / 700 / 800 | 210 / 450 / 600 | General purpose — most common SS fastener |
| A4 | Austenitic (Mo-bearing) | SS 316 / 316L | -50 / -70 / -80 | 500 / 700 / 800 | 210 / 450 / 600 | Marine, chemical, chloride service |
| A5 | Austenitic (stabilised) | SS 321 / 347 | -50 / -70 | 500 / 700 | 210 / 450 | High temp service, sensitisation resistant |
| F1 | Ferritic | SS 430 | -45 / -60 | 450 / 600 | 250 / 410 | Magnetic, moderate corrosion resistance |
| C1/C3/C4 | Martensitic | SS 410/416/420 | Various | 800–1000+ | 600–800+ | High strength, moderate corrosion only |
PTFE Coated Fasteners
ASTM A193 / A194 base · PTFE coating per MIL-L-23398 / Xylan 1424
Steel or alloy fasteners with a thin, uniformly applied PTFE (polytetrafluoroethylene) or Xylan fluoropolymer coating. Dramatically reduces installation torque, prevents galling on SS threads, and provides corrosion protection. Colour-coded by specification.
- Coating TypesPTFE (white/clear) · Xylan 1424 (blue) · Xylan 1070 (red/yellow) · Molykote (grey)
- Base MaterialASTM A193 B7 · B8 / B8M SS · Carbon Steel · Duplex · Alloy steel
- Coating Thickness12–25 microns (standard) · Up to 40 microns (heavy coat)
- Size RangeM6 to M100 · ¼″ to 4″
- Key BenefitAnti-galling on SS fasteners — reduces K-factor (nut factor) from ~0.2 to ~0.12
- Temp. Range-70°C to +260°C (PTFE coating)
- Salt Spray (ASTM B117)500–1000 hrs (Xylan 1424 on carbon steel)
- Chemical ResistanceExcellent — resists most acids, alkalis, solvents. Consult datasheet for specific media.
- Colour CodeBlue (Xylan 1424 std.) · Green (B8M) · Red (B7 special) · Yellow (L7)
- ApplicationOffshore, chemical plant, subsea, high-cycle flanges, SS-to-SS joints
MIL-L-23398Xylan 1424 ASTM B117ASTM A193 base
Hot Dip Galvanised Fasteners
ASTM A153 · ISO 1461 · EN ISO 10684 · BS 729
Fasteners immersed in molten zinc at ~450°C forming a metallurgically bonded zinc-iron alloy coating. Superior corrosion protection versus electroplating — suitable for outdoor, marine, and aggressive atmospheric environments. Threads re-tapped after galvanising to maintain fit.
- ProcessHot dip galvanising per ASTM A153 Class C/D or ISO 1461
- Coating Thickness45–85 microns (ISO 1461) · 55–65 microns (ASTM A153 Class C)
- Base MaterialCarbon Steel Cl.4.6 / 5.6 / 8.8 · ASTM A307 / A325 · A193 B7
- Size RangeM6 to M100 · ¼″ to 4″
- Thread AllowanceNuts over-tapped to 6AZ tolerance after galvanising to accommodate zinc build-up
- Salt Spray1000–3000 hrs (ASTM B117) vs. ~200 hrs electroplated zinc
- Service Life50–100 years in rural atmosphere · 15–30 years in marine environment
- Not SuitableSS equipment (galvanic couple) · Acids below pH 6 · Strong alkalis above pH 12.5
- Dimensional Std.Thread tolerance oversize per ISO 965-4 / ASME B1.1 (allowance for coating)
ASTM A153ISO 1461 EN ISO 10684BS 729ASTM B117
Eye Bolts & Foundation Bolts
DIN 580 (Eye Bolt) · DIN 444 (Ring Bolt) · ASME B18.15
Lifting eye bolts with a looped head for attachment of hooks, shackles, and wire ropes. Foundation / J-bolts anchor equipment to concrete plinths. Available in plain, galvanised, and SS for corrosive environments. Must be rated for the intended load — not interchangeable with structural bolts.
- Eye Bolt TypesCollar type (DIN 580) · Ringbolt (DIN 444) · Swivel eye · Strap / plate eye
- Foundation Bolt TypesL-bolt · J-bolt · T-bolt · Straight rod with plate · Anchor bolt with nut
- Size Range (Eye Bolt)M6 to M64 (DIN 580)
- Size Range (Foundation)M12 to M100 · custom lengths to 3000 mm
- WLL (M24 collar eye bolt)~3 tonne axial / ~1.8 tonne at 45° / ~0.6 tonne at 90° — load-angle critical
- CS GradesS235 / S355 (structural) · ASTM A36 · Grade 4.6 / 5.6
- SS GradesSS 304 / 316 (marine, chemical)
- FinishSelf colour · Zinc plated · Hot dip galvanised · Stainless
DIN 580DIN 444 ASME B18.15BS 4278
U-Bolts & J-Bolts
DIN 3570 (pipe clamp U-bolt) · ASME B18.29.1
U-bolts are used to clamp pipe, conduit, and structural shapes to supports. J-bolts serve as anchor bolts embedded in concrete. Both supplied in matched thread and nut sets. Pipe clamp U-bolts dimensioned to match nominal pipe size (NPS) OD.
- U-Bolt TypesRound bend (pipe clamp) · Square bend (structural) · Semi-round · Long / short leg
- J-Bolt TypesStandard J · Long J · Hook bolt · Anchor J (embedded)
- Pipe Size Range (U-bolt)NB ½″ to 60″ (matched to pipe OD per ASME B36.10M)
- Rod DiameterM8 to M52 · ⅜″ to 2″
- CS / HT GradesASTM A307 · A193 B7 · ISO Cl.4.6 / 5.6 / 8.8
- SS GradesSS 304 / 316 (marine, offshore pipe supports)
- Finish OptionsPlain · Zinc plated · Hot dip galvanised · Electro-polished SS
- Custom Dims.Inside radius, leg length, and thread length all customisable on request
DIN 3570ASME B18.29.1ASTM A307 / B7
Fastener Surface Finish & Coating Comparison
| Finish / Coating | Thickness | Salt Spray (ASTM B117) | Temp. Limit | Std. | Best For | Not For |
|---|---|---|---|---|---|---|
| Plain / Self Colour | Nil | <24 hrs | No limit (base metal) | — | Dry indoor, immediate painting | Any corrosive exposure |
| Black Oxide | 1–2 µm | <100 hrs (oiled) | +120°C | MIL-DTL-13924 | Oiled assemblies, minimal friction change | Outdoor / wet service |
| Electroplated Zinc | 5–12 µm | 72–200 hrs | +120°C | ISO 4042 / ASTM B633 | Light corrosion protection, indoor | Marine / offshore |
| Mechanical Zinc (Sherardised) | 15–30 µm | 200–500 hrs | +250°C | ISO 17668 / BS 4921 | High-strength bolts (no H₂ embrittlement risk) | Extreme environments |
| Hot Dip Galvanised | 45–85 µm | 1000–3000 hrs | +200°C | ASTM A153 / ISO 1461 | Outdoor, structural, pipeline supports | SS contact (galvanic), acids pH<6 |
| PTFE / Xylan Coating | 12–25 µm | 500–1000 hrs | +260°C | MIL-L-23398 / Xylan 1424 | Anti-galling SS, high-cycle flanges, offshore | Abrasive / impact environments |
| Dacromet / Geomet | 8–12 µm | 720–1000 hrs | +300°C | ISO 10683 | Automotive, high temp corrosion protection | Where zinc contact is a concern |
| Nickel Plated | 5–25 µm | 200–500 hrs | +300°C | ISO 1456 / ASTM B689 | Aesthetics, food equipment, moderate corrosion | Strong acid or alkali media |
Threaded Rods (All-Thread / Studding)
DIN 975 / 976 · ISO 888 · ASTM F1554 · BS 4882
Fully threaded rod supplied in standard 1 m or 3 m lengths, or cut to custom lengths. Used as stud bolts (cut to length), hanger rods, anchor rods, and connecting rods. Available coarse and fine thread in all MOCs.
- TypesAll-thread (DIN 975 coarse / DIN 976 fine) · Metric studding · Imperial threaded rod
- Metric Size RangeM4 to M100
- Imperial Size Range¼″ to 4″ UNC / UNF / 8UN
- Standard Lengths1000 mm · 2000 mm · 3000 mm · custom cut lengths
- Thread PitchCoarse (standard) · Fine · Left-hand thread on request
- CS / HT GradesISO: Cl.4.8 / 5.8 / 8.8 · ASTM A307 · F1554 Gr.36/55/105 · A193 B7 (alloy)
- SS GradesISO 3506 A2-70 (SS 304) · A4-70 (SS 316) · A4-80 · ASTM A193 B8/B8M
- Duplex GradesUNS S31803 / S32750 per ASTM A276 / A479
- Brass GradesCuZn39Pb3 (CW614N) · CuZn40Pb2 (CW617N) per EN 12164
- FinishPlain · Zinc plated · Hot dip galvanised · PTFE coated · Stainless bright
- Tolerance6g thread tolerance (standard) · 6H nut · Left/right combination available
DIN 975/976ASTM F1554 ISO 888BS 4882A193 B7
Coupling Nuts & Extension Nuts
DIN 6334 · ISO 4033 · ASME B18.2.2
Long hex or round coupling nuts used to join two threaded rods end-to-end, or to extend bolt length. Slotted coupling nuts allow length adjustment. Used extensively with all-thread rod assemblies in pipe hangers and support systems.
- TypesHex coupling nut (DIN 6334) · Reducing coupling nut · Round coupling nut · Slotted (adjustable)
- Size RangeM4 to M100 metric · ¼″ to 4″ imperial
- LengthTypically 3× nominal diameter (DIN 6334)
- CS / HT GradesISO Cl.6 / 8 / 10 · ASTM A194 2H
- SS GradesISO 3506 A2-70 / A4-70 · A4-80
- Duplex / BrassUNS S31803 · CuZn39Pb3
DIN 6334ISO 4033ASME B18.2.2
Threaded Rod — Size, Pitch & Weight Reference (DIN 975 / ISO Metric)
| Size | Pitch (Coarse mm) | Pitch (Fine mm) | Minor Dia. (mm) | Stress Area (mm²) | Weight (kg/m) approx. | Tensile Capacity Cl.8.8 (kN) |
|---|---|---|---|---|---|---|
| M10 | 1.50 | 1.25 | 8.16 | 58.0 | 0.617 | 41.8 |
| M12 | 1.75 | 1.25 | 9.85 | 84.3 | 0.888 | 60.7 |
| M16 | 2.00 | 1.50 | 13.55 | 157 | 1.578 | 113 |
| M20 | 2.50 | 1.50 | 16.93 | 245 | 2.466 | 176 |
| M24 | 3.00 | 2.00 | 20.32 | 353 | 3.551 | 254 |
| M30 | 3.50 | 2.00 | 25.71 | 561 | 5.544 | 404 |
| M36 | 4.00 | 3.00 | 31.09 | 817 | 7.990 | 588 |
| M42 | 4.50 | 3.00 | 36.48 | 1121 | 10.96 | 807 |
| M48 | 5.00 | 3.00 | 41.87 | 1473 | 14.21 | 1060 |
| M56 | 5.50 | 4.00 | 48.86 | 2030 | 19.29 | 1462 |
| M64 | 6.00 | 4.00 | 55.84 | 2676 | 25.46 | 1927 |
| M72 | 6.00 | 4.00 | 63.01 | 3460 | 32.16 | 2491 |
| M80 | 6.00 | 4.00 | 70.01 | 4344 | 40.12 | — |
Weight based on steel density 7.85 kg/dm³. Tensile capacity = Stress Area × Min. UTS (800 MPa for Cl.8.8) / 1000. Verify with structural engineer for load-bearing applications. Imperial threaded rod weight tables available on request.
Materials of Construction
Fastener MOC Overview
Material selection is critical — wrong MOC causes galvanic corrosion, hydrogen embrittlement, galling, or service failure. Match fastener MOC to flange, equipment, and service requirements.
Stainless Steel
Most widely specified for corrosive process service. Austenitic grades are non-magnetic, highly corrosion resistant, and cryogenic compatible. Prone to galling — use PTFE coating or anti-seize compound on SS-to-SS threads.
- Grades304 / 304L · 316 / 316L · 321 · 347 · 310S · 904L
- Bolt Std.ASTM A193 B8 / B8M / B8T / B8C · ISO 3506 A2/A4
- Nut Std.ASTM A194 8 / 8M / 8T / 8C · ISO 3506 A2/A4
- Temp. Range-196°C to +816°C (grade dep.)
- Galling RiskHIGH — always use PTFE coating or Molykote paste
- Hardness Max.HRC 35 (sour service per NACE MR0175)
High Tensile / Alloy Steel
Chromium-molybdenum alloy steel heat-treated to achieve high tensile strength. B7 is the workhorse of pressure flange bolting globally. Must be protected against corrosion — bare B7 in outdoor service rusts rapidly.
- GradesASTM A193 B7 / B7M / B16 / L7 / L7M · ISO Cl.8.8 / 10.9 / 12.9
- Base AlloyAISI 4140 / 4142 (Cr-Mo) · 4340 (Ni-Cr-Mo) · 4130
- Nut Std.ASTM A194 2H (B7) · 4 (L7) · 7 (B16) · ISO 898-2 Cl.8/10/12
- Min. Yield (B7)725 MPa (≤2½″) · 655 MPa (2⅝″–4″)
- Temp. RangeB7: -45°C to +450°C · L7: -100°C to +450°C
- NACE ServiceUse B7M (controlled hardness ≤235 HBW / ≤22 HRC)
Carbon Steel
Standard carbon steel fasteners for general structural, utility, and non-critical process applications. Low cost, widely available. Require coating or painting in corrosive or outdoor environments.
- GradesASTM A307 Gr.A/B · SAE Gr.2 / Gr.5 / Gr.8 · ISO Cl.4.6 / 5.6 / 6.8 / 8.8
- Nut GradesASTM A194 2H · ISO 898-2 Cl.5 / 6 / 8 · DIN 934 Cl.8
- Temp. Range-29°C to +300°C (standard) · -45°C with impact tested grades
- Hydrogen Emb.Risk above 10.9 class if electroplated — use mechanical zinc or HDG
- ApplicationsStructural steel, equipment bases, pipe supports, general machinery
Duplex / Super Duplex SS
Higher yield strength than austenitic SS — allows smaller diameter bolts for same clamping load. Superior chloride SCC resistance. Preferred for offshore, seawater, and high-chloride chemical service.
- Duplex GradeUNS S31803 / S32205 (2205)
- Super DuplexUNS S32750 (SAF 2507) / S32760 (Zeron 100)
- Bolt Std.ASTM A276 / A479 · EN 10088 · custom per project spec
- Min. Yield (2205)450 MPa (vs. 207 MPa for B8 Cl.1 SS 304)
- PRENDuplex ≥35 · Super Duplex ≥40
- Temp. Range-50°C to +300°C
- Hardness Limit≤28 HRC per NACE MR0175 (sour service)
Brass / Copper Alloys
Excellent machinability, corrosion resistance in water and mild chemicals, and natural antimicrobial properties. Used in plumbing, HVAC, instrumentation, and electrical applications. Not for ammonia or acetylene service.
- Brass GradesCuZn39Pb3 (CW614N) · CuZn40Pb2 (CW617N) · CuZn36 (CW507L)
- Cu-Ni GradesC70600 (90/10) · C71500 (70/30) for marine service
- Bolt Std.ISO 8839 · EN 12164 · ASTM B21 / B16
- Hardness~75–100 HRB (brass); lower than steel — check torque specs
- Temp. Range-200°C to +200°C
- Not ForAmmonia · Acetylene · Moist H₂S · Strong oxidising acids
- ApplicationsPlumbing fittings, electrical terminals, instrumentation, HVAC, Marine
MOC × Application Suitability Matrix
| Service Condition | Carbon Steel | HT Alloy B7 | SS 304 / A2 | SS 316 / A4 | Duplex 2205 | Brass |
|---|---|---|---|---|---|---|
| General process (ambient) | ✓ (coated) | ✓ (coated) | ✓ | ✓ | ✓ | ✓ |
| High temperature (>300°C) | Limited | ✓ B7/B16 | ✓ B8T/B8C | ✓ B8M | Limited (<300°C) | ✗ |
| Low temperature (<-45°C) | ✗ | ✓ L7/L7M | ✓ Cl.1 annealed | ✓ Cl.1 annealed | ✓ | ✓ |
| Sour service (H₂S / NACE) | ✗ | ✓ B7M only | ✓ B8M Cl.1 | ✓ B8M Cl.1 | ✓ (<28 HRC) | ✗ |
| Marine / seawater | ✗ (bare) | ✓ HDG only | Limited (Cl⁻ SCC risk) | ✓ | ✓ (preferred) | ✓ Cu-Ni only |
| Chemical / acid service | ✗ | ✗ | ✓ (non-chloride) | ✓ | ✓ | Limited |
| Cryogenic (<-100°C) | ✗ | ✓ L7M | ✓ B8 Cl.1 | ✓ B8M Cl.1 | ✓ | ✓ |
| Outdoor / atmospheric | ✓ HDG / PTFE | ✓ HDG / PTFE | ✓ | ✓ | ✓ | ✓ |
| Food / pharma | ✗ | ✗ | ✓ (electropolished) | ✓ (preferred) | Limited | Limited |
| Plumbing / HVAC / utility | ✓ (galv.) | — | ✓ | ✓ | — | ✓ (ideal) |
International Compliance
Export Standards
All fasteners shipped with EN 10204 3.1 / 3.2 Mill Test Certificates, hardness test reports, dimensional inspection reports, and country-of-origin documentation. Third-party inspection available on request.
ASTM / ASME
American Society for Testing & Materials / Mechanical Engineers
A193A194 A307A325A490 F1554A153B633 B18.2.1B18.2.2B18.15 B18.22.1B18.29.1
ISO
International Organisation for Standardisation
ISO 898-1ISO 898-2 ISO 3506ISO 4014 ISO 4017ISO 4032 ISO 4033ISO 965 ISO 1461ISO 7089 ISO 8839ISO 10683 ISO 15156 (NACE)
DIN / EN
Deutsches Institut für Normung / European Norm
DIN 931DIN 933 DIN 934DIN 935 DIN 975DIN 976 DIN 985DIN 6334 DIN 580DIN 3570 EN 14399EN ISO 4014 EN ISO 10684
BS
British Standards Institution
BS 4882BS 1769 BS 4190BS 3692 BS 4933BS 729 BS 4921BS 4278 BS EN 14399
Fastener Standards Cross-Reference
| Fastener Type | ASTM / ASME (US) | ISO (Metric) | DIN (German) | EN (European) | BS (British) |
|---|---|---|---|---|---|
| Hex Bolt (partial thread) | ASME B18.2.1 | ISO 4014 | DIN 931 | EN ISO 4014 | BS 3692 / BS 4190 |
| Hex Bolt (full thread) | ASME B18.2.1 | ISO 4017 | DIN 933 | EN ISO 4017 | BS 3692 |
| Hex Nut (standard) | ASME B18.2.2 | ISO 4032 | DIN 934 | EN ISO 4032 | BS 3692 / BS 4190 |
| Heavy Hex Nut | ASME B18.2.2 | — | — | — | BS 4882 |
| Stud Bolt (flange) | ASTM A193 / ASME B16.5 | ISO 888 | DIN 976 | EN ISO 888 | BS 4882 / BS 1769 |
| Threaded Rod | ASTM F1554 | ISO 888 | DIN 975 / 976 | EN ISO 888 | BS 4882 |
| Structural Bolt (HT) | ASTM A325 / A490 | ISO 898-1 Cl.8.8/10.9 | — | EN 14399-3/4 | BS EN 14399 |
| Stainless Bolt | ASTM A193 B8/B8M | ISO 3506 A2/A4 | DIN 931 + A2/A4 mark | EN ISO 3506-1 | BS EN ISO 3506 |
| Plain Washer | ASME B18.22.1 | ISO 7089 / 7090 | DIN 125 | EN ISO 7089 | BS 4320 |
| Eye Bolt | ASME B18.15 | — | DIN 580 / 444 | — | BS 4278 |
| Hot Dip Galvanising | ASTM A153 | ISO 1461 | — | EN ISO 10684 | BS 729 |
| PTFE / Fluoropolymer Coat | MIL-L-23398 | — | — | — | — |
Engineering Reference
Fastener Selection Guide
Quick reference for procurement and engineering teams. Selection must also account for flange material, gasket type, bolting pattern, and ASME / EN design code requirements.
By Flange Pressure Class (ASME B16.5)
| Flange Class | Std. Bolt Grade | Std. Nut Grade | Bolt Type | Min. Yield Required | Notes |
|---|---|---|---|---|---|
| Class 150 | ASTM A193 B7 | A194 2H | Stud bolt, fully threaded | 725 MPa | Most CS/alloy flanges; also A2-70 SS for SS flanges |
| Class 300 | ASTM A193 B7 | A194 2H | Stud bolt, fully threaded | 725 MPa | Standard B7/2H combination |
| Class 600 | ASTM A193 B7 | A194 2H | Stud bolt, fully threaded | 725 MPa | Higher bolt preload required — verify torque calculations |
| Class 900 | ASTM A193 B7 | A194 2H | Stud bolt, fully threaded | 725 MPa | Higher preload — B7M if sour service |
| Class 1500 | ASTM A193 B7 / B16 | A194 2H / 7 | Stud bolt, fully threaded | 725 / 724 MPa | B16 for high-temp steam above 450°C |
| Class 2500 | ASTM A193 B7 / B16 | A194 2H / 7 | Stud bolt, fully threaded | 725 / 724 MPa | Critical HP/HT — verify per design calculations |
| SS Flanges (any class) | ASTM A193 B8M Cl.2 | A194 8M | Stud bolt + PTFE coating | 552 MPa | PTFE coating mandatory to prevent galling |
By Finish — When to Specify What
| Requirement | Specify This Finish | Standard Ref. | Important Note |
|---|---|---|---|
| Outdoor / structural (mild atmosphere) | Hot Dip Galvanised | ASTM A153 / ISO 1461 | Re-tap nut threads to 6AZ after galvanising |
| Offshore / marine atmosphere | HDG + Xylan / PTFE topcoat | ASTM A153 + Xylan 1424 | Two-coat system for maximum protection |
| SS-to-SS mating threads | PTFE / Xylan 1424 on SS bolts | MIL-L-23398 | Critical — bare SS-to-SS galls and seizes irreversibly |
| High-strength bolt (>10.9 / >12.9) | Mechanical zinc / Geomet / bare | ISO 17668 / ISO 10683 | Avoid electroplating — hydrogen embrittlement risk |
| Food / pharma / clean room | Electropolished SS 316 | ASTM B912 / ISO 3506 A4 | Removes surface contamination, improves corrosion resistance |
| Subsea / splash zone | SS Duplex + Xylan 1424 PTFE | NORSOK / project spec | Combined MOC upgrade + coating for maximum life |
| General indoor machinery | Zinc electroplated (5–8 µm) | ISO 4042 / ASTM B633 | Not for outdoor or wet service without topcoat |
Get in Touch
Tell us the fastener type, grade, size, finish, and destination — we'll respond within 24 hours with pricing, datasheet, and lead time.
- EN 10204 3.1 / 3.2 Mill Test Certificates with every order
- Hardness test reports (HRC / HBW / HV) for all HT and alloy grades
- PMI (Positive Material Identification) for SS, Duplex, and Alloy grades
- NACE MR0175 / ISO 15156 compliance documentation on request
- Third-party inspection — SGS, TÜV, BV, Lloyd's Register on request
- Export packing with moisture protection for international shipments
- Full traceability — heat number, lot, COO, and dimensional report
- Pre-assembled kits (bolt + nut + washers) per ASME B16.5 bolt chart
