Product
Product Details
Copper Hex Bolts, Copper Bolts
Copper Hex Bolts | Copper Bolts
Pricing: US$ 15.80 / Kilogram (FOB India | MOQ: 50 Kg | Custom grades on request)
Electrical Accessories India manufactures and exports copper hex bolts and copper bolts conforming to DIN 933, DIN 931, ISO 4014, and ASME B18.2.1 standards. Produced from high-conductivity electrolytic tough pitch (ETP) copper grades C101, C110, and C122, these copper fasteners are engineered for electrical bus-bar assemblies, earthing systems, switchgear panels, transformer terminals, and power distribution equipment. With inherent corrosion resistance, low contact resistance, and excellent machinability, copper hex bolts serve as the fastener of choice for electrical OEMs, EPC contractors, power utilities, renewable energy project developers, and industrial distributors across North America, Europe, the Middle East, and Asia-Pacific.
Product Overview – Copper Hex Bolts and Copper Bolts
Copper hex bolts—also referenced in procurement specifications as copper hexagonal bolts, copper threaded fasteners, copper through-bolts, copper machine bolts, copper full-thread bolts, copper cap screws, and copper structural bolts—represent a critical sub-category within copper precision-machined parts. These components are cold-forged or hot-forged from copper rod stock, then threaded on CNC thread-rolling or cutting machines to deliver dimensional accuracy within ISO tolerance class 6g.
Electrical Connectivity Applications: In high-current bus-bar joints, earthing grids, grounding conductor lugs, lightning protection systems, HT/LT transformer terminal connections, and panel board assemblies, copper bolts provide not only mechanical clamping but also serve as an integral electrical conductor. Their conductivity—typically 100% IACS for C101 grade—ensures negligible voltage drop across the joint, which is critical in load-break switchgear, ring main units (RMUs), and SF6 circuit breaker assemblies.
Corrosion Resistance and Longevity: Unlike zinc-plated steel fasteners, copper hex bolts resist atmospheric corrosion, chemical attack from H₂S and SO₂, and galvanic corrosion when installed in copper bus-bar systems. They are routinely specified for coastal and offshore electrical installations, chemical processing plants, fertilizer units, oil & gas refineries, marine switchgear, and metro/rail traction systems where long service life and low maintenance are mandatory.
Raw Material and Traceability: All copper bolts are manufactured from prime copper rod conforming to IS 191, BS EN 13601, ASTM B187, or DIN EN 1977. Each batch is traceable to mill test certificates (MTCs) verifying chemical composition, hardness, and conductivity. Standard grades offered include C10100 (oxygen-free), C11000 (ETP), C12200 (DHP phosphorus-deoxidized), and C14500 (free-machining tellurium copper).
Thread Forms and Drive Types: Available in metric coarse thread (DIN 13), metric fine thread, Unified National Coarse (UNC), and Unified National Fine (UNF). Head configurations include full hex, reduced hex (semi-finished), and square head. Partial thread (DIN 931) and full thread (DIN 933) versions are stocked in sizes M3 through M36, length range 6 mm to 300 mm.
Surface Treatments: Copper bolts are supplied in natural copper finish (bright), pickled/passivated, nickel-plated (EN 1.4 μm min), tin-plated (ASTM B545), silver-plated (ASTM B700), and lacquered. Plating enhances oxidation resistance in tropical, high-humidity, and salt-laden environments and reduces contact resistance at terminal joints.
Equivalent Industry Terms: These products are also procured under trade descriptions such as copper bolt and nut sets, copper anchor bolts, copper stud bolts, copper foundation bolts, copper anti-vibration fasteners, copper U-bolts, copper J-bolts, and copper eyebolts. Custom non-standard configurations are accepted against customer drawings and 3D models.
Key Features of Copper Hex Bolts
- High electrical conductivity: ≥ 100% IACS (C10100 grade) to ≥ 98% IACS (C11000 grade)
- Manufactured to DIN 933 / DIN 931 / ISO 4014 / ISO 4017 / ASME B18.2.1
- Size range: M3 to M36 (metric) | 1/4″ to 1-1/2″ (imperial)
- Length range: 6 mm to 300 mm (custom lengths accepted)
- Thread tolerance: ISO 6g (external) per ISO 965
- Tensile strength: 200–350 MPa depending on grade and temper
- 100% dimensional inspection per drawing; Rockwell hardness test included
- RoHS-compliant copper alloys; REACH-compliant surface treatments
High Electrical Conductivity
Copper grade C11000 (ETP) delivers ≥ 98% IACS conductivity—roughly 5–7× better than 304 stainless steel bolts—making copper hex bolts the standard for bus-bar, earthing, and terminal assembly applications. Oxygen-free C10100 grade, used in vacuum interrupters and sensitive electronics earthing, achieves ≥ 100% IACS. Conductivity is verified by eddy-current testing per ASTM E1004 on each production batch. Low joint resistance directly reduces I²R heating losses in power distribution panels, contributing to energy efficiency compliance (IS 15936, IEC 62053).
Dimensional Accuracy and Thread Integrity
CNC thread-rolling produces a burnished thread form that is stronger than cut threads by approximately 20–30% due to work-hardening of the thread root. Thread gauging is performed with GO/NO-GO thread ring gauges calibrated to NABL-accredited standards. Hex head dimensions conform to DIN EN ISO 4032 (nut pairing) tolerances. Part-to-part dimensional repeatability is maintained within ±0.02 mm for critical bus-bar holes, critical for multi-bolt flange joints in switchgear assemblies, power capacitor banks, and surge arrester bases.
Corrosion and Chemical Resistance
ETP and DHP copper bolts resist oxidation up to 200 °C, seawater corrosion (MIL-DTL-24631 equivalent), sulfur dioxide (SO₂) atmospheres in chemical plants, and hydrogen sulfide (H₂S) exposure in oil & gas environments. Salt spray testing per ASTM B117 (500 hours minimum) demonstrates no pitting or delamination on tin-plated and nickel-plated variants. For marine switchgear and offshore transformer enclosures, copper bolts eliminate the bimetallic corrosion (galvanic cell) that occurs when dissimilar metal fasteners contact copper bus-bars.
Versatile Surface Finishes
Bright copper (as-machined), chemical passivation, tin plating (ASTM B545 / IEC 60068-2-52), nickel plating (ASTM B689 / DIN 50966), silver plating (ASTM B700 / BS EN ISO 4521), and organic lacquer coatings are offered. Plated fasteners conform to RoHS 2 (2011/65/EU) Annex II (lead-free solder exemption). All plating thickness measured by XRF per ASTM B568. Silver-plated copper bolts are specified for GIS (Gas-Insulated Switchgear) interfaces, current transformer (CT) primary connections, and railway overhead equipment (OHE) connections where tarnish-free contact is mandatory.
Compliance with International Standards
Our copper bolts are manufactured under ISO 9001:2015 QMS and tested to DIN 933, DIN 931, ISO 4014, ISO 4017, ASME B18.2.1, BS EN ISO 4016, and IS 1367. Material conformity certificates per EN 10204 Type 3.1 are supplied with every order. Traceability chain from copper cathode (LME-registered) to finished bolt is maintained via heat numbers, lot numbers, and batch records. Export documentation includes CE marking declaration (where applicable), REACH/RoHS compliance declaration, and country of origin certificate for import duty classification.
Custom Configurations and Special Requirements
Non-standard bolt heads (flange head, T-head, round head, truss head), special drives (Torx, internal hex/Allen, Phillips), left-hand threads, fine pitch threads, and non-standard lengths are produced per customer CAD drawings (STEP/DXF/DWG). Low-volume prototype runs (25 pieces minimum) are accepted for R&D and type-testing. For OEM electrical equipment manufacturers, Kanban supply with EDI-linked inventory management is available. Bar-coding and laser marking per IEC 60062 color band equivalent for part identification are offered as value-added services.
Technical Specifications
| Parameter | Specification |
|---|---|
| Product | Copper Hex Bolt / Copper Bolt |
| Standards | DIN 933, DIN 931, ISO 4014, ISO 4017, ASME B18.2.1, IS 1367 |
| Material Grades | C10100, C11000, C12200, C14500 (see table below) |
| Size Range (Metric) | M3 × 0.5 to M36 × 4.0 |
| Size Range (Imperial) | 1/4″-20 UNC to 1-1/2″-6 UNC |
| Length Range | 6 mm to 300 mm (custom lengths available) |
| Thread Tolerance | 6g (external) per ISO 965-1 |
| Head Wrench Size | Per DIN EN ISO 4032 / ASME B18.2.2 |
| Tensile Strength | 200 MPa min (annealed) – 350 MPa (half-hard) |
| Hardness | 60–95 HRB (depending on temper) |
| Conductivity | 98–101% IACS |
| Surface Finish | Bright / Tin-plated / Nickel-plated / Silver-plated |
| Packing | Polybag + carton or bulk bag; export packing on request |
| Lead Time | 2–4 weeks standard; 1 week express (subject to stock) |
Copper Raw Material Grades and International Equivalents
| UNS (USA) | EN (Europe) | BS (UK) | DIN (Germany) | IS (India) | JIS (Japan) | Description |
|---|---|---|---|---|---|---|
| C10100 | CW008A | C101 | E-Cu99.99 | — | C1011 | Oxygen-Free High Conductivity (OFHC) |
| C11000 | CW004A | C101 | E-Cu58 | ETP Copper | C1100 | Electrolytic Tough Pitch (ETP) |
| C12200 | CW024A | C106 | SF-Cu | DHP Copper | C1220 | Phosphorus Deoxidized (DHP) |
| C14500 | CW118C | C109 | CuTeP | — | C1450 | Tellurium Copper (Free-Machining) |
Product Types and Variants
| Type | Standard | Thread | Use Case |
|---|---|---|---|
| Full Thread Hex Bolt | DIN 933 / ISO 4017 | Metric Coarse/Fine | Electrical panel assembly, bus-bar joints |
| Partial Thread Hex Bolt | DIN 931 / ISO 4014 | Metric Coarse | Flange joints, structural earthing |
| UNC/UNF Hex Bolt | ASME B18.2.1 | Imperial UNC/UNF | USA/Canadian electrical OEM equipment |
| Stud Bolt (All-Thread) | DIN 976 | Metric / BSP | Transformer terminals, cable box connections |
| Foundation / Anchor Bolt | Customer drawing | Metric Coarse | Earthing electrodes, surge arrester bases |
| T-Head Bolt | DIN 186 | Metric Coarse | Rail traction OHE fittings |
| Flange Bolt | DIN 6921 | Metric Coarse | GIS bus-duct flange, MV cable joints |
Applications by Industry
| Industry / Application | Copper Bolt Application |
|---|---|
| Power Transmission and Distribution | Bus-bar assembly bolts, transformer terminal bolts, switchgear flange bolts |
| Renewable Energy (Solar / Wind) | Earthing grid fasteners, inverter terminal bolts, cable tray fasteners |
| Railways and Metro | Overhead Equipment (OHE) fittings, traction return rail bonding bolts |
| Oil and Gas / Petrochemical | Earthing/bonding fasteners in hazardous area (ATEX/IECEx) installations |
| Marine and Offshore | Hull earthing bolts, shore power connection bolts, switchboard fasteners |
| Industrial Manufacturing | Machine tool earthing, control panel assembly, motor terminal connections |
| Telecommunications | Tower earthing fasteners, BTS grounding bolts, data center PDU connections |
| Defence and Aerospace | Shielding/bonding fasteners for EMI/RFI protection, MIL-spec applications |
Manufacturing Process
Copper hex bolts are manufactured through a controlled multi-step process: (1) Raw Material Incoming Inspection – copper rod is tested for chemical composition (ICP spectroscopy), conductivity (eddy-current), and hardness before acceptance. (2) Cold Heading / Hot Forging – heads are formed by cold heading (M3–M16) or hot forging (M20–M36) on dedicated copper bolt-makers; forging temperature is maintained at 600–750 °C to prevent grain growth. (3) Thread Rolling / Thread Cutting – threads are rolled (preferred) or cut using form-relieved taps with precision CNC control; thread form meets ISO 965-1 6g tolerance. (4) Heat Treatment (where specified) – annealing at 300–600 °C restores ductility after cold working. (5) Plating and Surface Treatment – electroplating is performed in barrel or rack lines per customer spec. (6) Inspection and Testing – 100% visual, dimensional sampling per AQL 1.0, conductivity testing on 10% of pieces, and GO/NO-GO thread gauging. (7) Packing and Documentation – material test certificates, compliance declarations, and packing lists accompany each shipment.
Quality Standards and Certifications
| Standard / Certification | Scope |
|---|---|
| ISO 9001:2015 | Quality Management System |
| DIN 933 / ISO 4017 | Full thread hex bolt dimensions |
| DIN 931 / ISO 4014 | Partial thread hex bolt dimensions |
| ASTM B187 / BS EN 13601 | Copper rod and bar chemical composition |
| EN 10204 Type 3.1 | Material test certificate with independent inspection |
| RoHS 2 / REACH | Restriction of hazardous substances |
| ASTM B117 | Salt spray / corrosion testing (500 h) |
| IEC 60068-2-52 | Salt mist cyclic test for plated components |
Why Choose Electrical Accessories India for Copper Hex Bolts?
Electrical Accessories India has over two decades of experience supplying copper precision parts to electrical OEMs, EPC contractors, and power utilities. Our copper bolt manufacturing facility is equipped with dedicated copper cold headers, CNC thread rollers, coordinate measuring machines (CMM), and in-house electroplating lines. We offer: single-source supply for all copper fastener requirements; NABL-traceable testing for conductivity, dimensions, and hardness; EN 10204 3.1 material certificates with every shipment; custom engineering against OEM drawings in 2–4 weeks; export packaging compliant with ISPM-15 for phytosanitary requirements; and competitive pricing at US$ 15.80/kg FOB India. We supply to clients across India, USA, UK, Germany, UAE, Australia, South Africa, and Singapore.
Frequently Asked Questions (FAQ)
Q1. What is the minimum order quantity for copper hex bolts?
Minimum order quantity is 50 kg for standard sizes. For custom non-standard sizes and special alloys (e.g., C10100 OFHC), MOQ is 100 kg. Sample orders of 1–5 kg are accepted for approved OEM qualification purposes at nominal sample charges.
Q2. What copper grade is recommended for bus-bar bolt applications?
C11000 (ETP copper) is the industry-standard grade for bus-bar fasteners, offering ≥ 98% IACS conductivity at competitive cost. Where higher conductivity is critical (e.g., precision earthing for substations), C10100 (OFHC) is specified.
Q3. What surface finish is recommended for outdoor / coastal installations?
Tin-plated (ASTM B545) or nickel-plated (ASTM B689) copper bolts are recommended for coastal, offshore, and tropical environments. Silver-plated bolts are preferred for high-current terminal connections in GIS and AIS substations, where oxidation-free contact is essential.
Q4. Can you supply to DIN 931 partial thread specification in M30 and M36?
Yes. We supply DIN 931 partial thread hex bolts in M30 × 3.5 and M36 × 4.0 in lengths up to 300 mm from C11000 ETP copper. Larger sizes can be produced from hot-forged copper billet stock against customer drawings.
Q5. Do you provide EN 10204 3.1 material test certificates?
Yes. EN 10204 Type 3.1 material test certificates from the copper rod manufacturer are standard. Third-party inspection (SGS, Bureau Veritas, TÜV) and witnessed testing can be arranged at additional cost.
Q6. What is the lead time for copper hex bolts?
Standard sizes (M6 to M20, DIN 933/931) carry 2–3 weeks lead time. Custom sizes and special alloys require 3–5 weeks. Express delivery within 7–10 days is available for stocked standard sizes upon written purchase order confirmation.
Q7. Are copper bolts RoHS and REACH compliant?
Yes. All copper alloys and plating chemicals used are RoHS 2 (2011/65/EU) and REACH (EC No. 1907/2006) compliant. Declaration of conformity is supplied with each shipment. Nickel and tin plating are lead-free (Pb-free) per IEC 62368-1 requirements.
Q8. Can custom thread forms like BSP or BSPT be provided?
Yes. BSP (G thread per ISO 228) and BSPT (R thread per ISO 7) are available for copper stud bolts and pipe-fitting bolts used in electrical conduit and bus-duct systems. BA thread and American pipe thread (NPT) are also produced on request.
Q9. What packaging is used for export shipments?
Export packing includes moisture-barrier polybag (VCI treated), inner carton with count label, and outer plywood or corrugated box complying with ISPM-15 phytosanitary standard. Gross weight, net weight, part number, and lot number are marked on each carton. Sea and air freight options are both available.
Q10. Do you offer custom marking or branding on copper bolts?
Yes. Laser marking, dot-peen marking, and cold-stamping of part numbers, customer logos, grade marks, and heat numbers can be applied to bolt heads or shanks per customer specifications. ISO 898-1 equivalent property class marking is also available.
Multilingual Equivalent Terms
| Language | Equivalent Terms |
|---|---|
| Spanish | Pernos hexagonales de cobre, Tornillos de cobre, Bulones de cobre |
| Russian | Медные шестигранные болты, Медные болты, Медные крепежные изделия |
| French | Boulons hexagonaux en cuivre, Boulons en cuivre, Vis de fixation en cuivre |
| Portuguese | Parafusos sextavados de cobre, Parafusos de cobre, Fixadores de cobre |
| Italian | Bulloni esagonali in rame, Bulloni in rame, Viti in rame |
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Request a Quote – Copper Hex Bolts
Electrical Accessories India | Manufacturer & Exporter of Copper Fasteners and Precision Parts
📧 Email: info@elecaccs.com
🌐 Website: elecaccs.com
📦 Price: US$ 15.80 / Kilogram (FOB India)
Lead Time: 2–4 weeks | MOQ: 50 Kg | Custom configurations accepted
Submit your drawing or specification to receive a detailed technical quotation within 24 business hours. We serve clients across India, USA, UK, Germany, UAE, Australia, Canada, Singapore, and South Africa.