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CW724R (CuZn21Si3P) Lead Free Brass Machining
CW724R (CuZn21Si3P) Lead Free Brass Machining – Lead Free Machined Parts
Electrical Accessories India manufactures precision CW724R (CuZn21Si3P) Lead Free Brass machined parts for electrical OEMs, EPC contractors, power utilities, and global distributors. CW724R, also designated CuZn21Si3P under EN 12164 / EN 12167, is a silicon-modified, low-lead (<0.09% Pb) Brass alloy engineered to comply with RoHS 2, ELV Directive, REACH, and NSF/ANSI 61 potable-water regulations. Our facility in India combines Swiss-type CNC turning, multi-axis machining, and rigorous ISO 9001:2015-certified quality control to deliver ready-to-install components with tight dimensional tolerances to global markets.
Product Overview
Alloy Chemistry and Designation
CW724R Brass is a ternary Copper–Zinc–Silicon alloy (Cu 75–77%, Zn balance, Si 2.7–3.5%, P 0.02–0.15%, Pb max 0.09%). The silicon addition replaces lead as the machinability-enhancing element, producing short chips in screw machining and CNC turning without generating hazardous swarf. Equivalent designations include CuZn21Si3P, 2.0492, UNS C87500-range, and DIN 17660 CuZn21Si3. The alloy delivers dezincification resistance, high corrosion resistance in potable water, and tensile strength of 490–630 MPa in the drawn condition.
Machined Parts, Turned Parts, and CNC Components
Our CW724R machined parts range covers precision turned components, CNC machined parts, screw machine components, automatic lathe parts, Swiss-type turned parts, collet-chuck components, bar-fed machined parts, multi-spindle machined parts, and single-spindle turned parts. All components are produced from EN 12164 (Brass rod for free machining) or EN 12167 (profiles, bars) certified stock with full mill test certificates.
Electrical and Plumbing Hardware
CW724R machined parts are routinely specified as contact pins, terminal blocks, earth bus bars, compression connectors, cable gland bodies, conduit fittings, valve bodies, manifold blocks, push-fit pipe fittings, and meter connection components. The lead-free composition makes them mandatory for potable water contact applications per EN 15664-1 and WRAS (Water Regulations Advisory Scheme) approval requirements.
Industrial Fasteners and Threaded Components
CW724R Lead Free Brass produces superior threaded fasteners including hex head bolts, socket head cap screws, machine screws, grub screws, studbolts, threaded inserts, stand-offs, spacers, hexagonal nuts, and flanged nuts. The alloy’s chip-breaking characteristics maintain thread-form integrity at fine pitches (M2–M48, UNC, UNF, BSP, NPT).
Hydraulic and Pneumatic Fittings
CW724R is widely used for hydraulic adaptors, pneumatic push-in fittings, compression sleeves, olive rings, ferrules, banjo bolts, pipe unions, elbow fittings, tee fittings, and cross-fittings manufactured to ISO 8434 and BSP/NPT thread standards. Its resistance to stress corrosion cracking in ammonia-bearing environments exceeds standard CuZn39Pb3 (CW614N).
Precision Housings and Enclosure Components
Precision machined enclosures, instrument housings, sensor bodies, transducer housings, actuator sleeves, solenoid valve bodies, motor end-caps, and connector backshells are produced from CW724R rod and extruded profile. Surface finishes achievable: Ra 0.4–3.2 μm; dimensional tolerance: IT6–IT8 to ISO 286-1.
OEM Sub-assemblies and Contract Machining
Electrical Accessories India provides complete sub-assembly services for CW724R machined components: press-fit assembly, o-ring insertion, thread locking, nickel plating, tin plating, silver plating, chromate passivation, and anodizing (on bi-metallic assemblies). MOQ from 500 pcs; large-volume contract machining up to 500,000 pcs/month.
Key Features
- RoHS 2 / ELV / REACH Compliant: Lead content <0.09% — fully compliant with EU Directive 2011/65/EU (RoHS 2) and ELV Directive 2000/53/EC.
- NSF/ANSI 61 Suitability: Safe for potable water contact, meeting North American drinking water standards.
- Superior Machinability: Machinability index ~70% (vs. free-cutting Brass CW614N at 100%), enabling high-volume automated production.
- Dezincification Resistance: Silicon content provides Class DZR performance; suitable for aggressive water conditions.
- High Tensile Strength: 490–630 MPa UTS; yield strength 300–500 MPa — excellent for structural and load-bearing components.
- Tight Tolerances: CNC turning centres achieve ±0.01 mm on critical dimensions; roundness <0.005 mm.
- Global Certifications: ISO 9001:2015, RoHS, REACH, WRAS (upon request).
Corrosion Resistance and Environmental Performance
CW724R offers excellent resistance to dezincification, pitting corrosion, and crevice corrosion in chlorinated water systems. The silicon matrix provides a protective oxide film, making parts suitable for marine environments, coastal electrical installations, chemical process equipment, and desalination plant components — without any surface coating. Salt spray resistance (ISO 9227): >500 hours without dezincification.
Machinability and Surface Quality
Although machinability of CW724R is lower than CW614N (leaded Brass), modern multi-axis CNC centres with carbide tooling achieve cycle times within 20–30% of leaded Brass, with superior surface finish Ra 0.4–0.8 μm on bearing surfaces. Swiss-type CNC lathes (Citizen, Star, Tsugami) are standard equipment for small-diameter precision parts (1–32 mm diameter). Bar-feed CNC turning centres handle larger diameters (up to 100 mm) for valve bodies and manifolds.
Mechanical Properties
CW724R in the drawn condition (R500 temper) has UTS 490–630 MPa, 0.2% proof stress 300–500 MPa, elongation A5 ≥5%, Brinell hardness 130–170 HB. Hot-forged and annealed grades offer higher ductility (A5 ≥15%) for complex assemblies requiring swaging or flaring. The alloy is non-magnetic and non-sparking, making it suitable for explosive atmospheres (ATEX zones) and MRI-compatible medical equipment housings.
Thermal and Electrical Properties
CW724R has thermal conductivity ~115 W/(m·K), electrical conductivity ~14.5% IACS, and thermal expansion 18.5 μm/(m·K). It maintains adequate conductivity for earth bonding strips, equipotential bonding connectors, lightning protection downlead clamps, grounding bars, and surge protector housings where both conductivity and lead-free compliance are required.
Plating and Surface Finishing
CW724R accepts all common surface treatments: bright nickel plating (EN/ISO 1456), tin-lead-free plating, silver plating, gold plating (for low-voltage contacts), zinc-nickel electroplating, chromate conversion coating, electroless nickel, powder coating, and lacquering. Parts are supplied bright polished, brushed, or as-machined per customer drawing.
Compliance and Traceability
Each lot is supplied with EN 10204 3.1 Mill Test Certificate, alloy composition by XRF analysis, RoHS conformity declaration, REACH SVHC declaration, and shipment documentation for import into EU, USA (TSCA), Canada, Australia, and Japan. Full material traceability from certified ingot to finished part is maintained.
Technical Specifications
| Parameter | Value / Range |
|---|---|
| Alloy Designation (EN) | CW724R / CuZn21Si3P |
| Copper (Cu) | 75.0 – 77.0% |
| Zinc (Zn) | Balance (~21%) |
| Silicon (Si) | 2.7 – 3.5% |
| Lead (Pb) max | 0.09% |
| Phosphorus (P) | 0.02 – 0.15% |
| Tensile Strength (UTS) | 490 – 630 MPa |
| 0.2% Proof Stress | 300 – 500 MPa |
| Elongation A5 | ≥ 5% |
| Brinell Hardness | 130 – 170 HB |
| Density | 8.5 g/cm³ |
| Thermal Conductivity | ~115 W/(m·K) |
| Electrical Conductivity | ~14.5% IACS |
| Machinability Index | ~70% (rel. to CW614N) |
| Lead compliance | RoHS 2, REACH, NSF/ANSI 61, ELV |
| Price (ex-works India) | US$ 11.50 / kg |
International Equivalent Grades
| Standard | Designation | Country/Region |
|---|---|---|
| EN 12164 / EN 12167 | CW724R / CuZn21Si3P | Europe (EU) |
| DIN 17660 | CuZn21Si3 | Germany |
| UNS | C87500 (approximate) | USA |
| JIS H 3250 | C8752 (approximate) | Japan |
| BS | CZ132 (approximate) | United Kingdom |
| ISO 426-1 | CuZn21Si3 | International |
| GOST | ЛМцС 50-1-1 (similar) | Russia / CIS |
| GB/T | HSi80-3 (approximate) | China |
Product Types / Variants
| Product Type | Process | Size Range | Typical Application |
|---|---|---|---|
| CNC Turned Parts | CNC Turning / Swiss-type | Ø1 – 65 mm | Contact pins, terminals, inserts |
| Screw Machine Parts | Multi-spindle automatic lathe | Ø3 – 40 mm | Fasteners, nipples, connectors |
| Milled Components | CNC milling / machining centres | Up to 200 × 200 mm | Housings, blocks, manifolds |
| Threaded Fasteners | Turning + thread rolling/cutting | M2 – M48, BSP, NPT | Bolts, studs, nuts, inserts |
| Tube and Pipe Fittings | CNC turning + boring | DN6 – DN50 | Compression fittings, elbows, tees |
| Custom OEM Parts | Multi-axis CNC (5-axis) | Per drawing | Sensors, actuators, valve bodies |
Applications by Industry
| Industry | Typical CW724R Parts |
|---|---|
| Electrical / Power Distribution | Earthing terminals, cable gland bodies, busbar connectors, compression lugs |
| Potable Water / Plumbing | Ball valve bodies, compression fittings, manifold blocks, meter unions |
| Oil & Gas | Instrument fittings, banjo bolts, nipples, adaptors (lead-free compliant) |
| Automotive | ELV-compliant connectors, sensor housings, fuel system fittings |
| HVAC / Refrigeration | Expansion valve bodies, refrigerant fittings, service valves |
| Electronics / Telecom | RF connector shells, coaxial connector bodies, PCB standoffs |
| Renewable Energy | Solar mounting hardware, wind turbine grounding connectors |
| Marine | Deck fittings, seacock components, bonding strips |
Manufacturing Process
Raw material (EN 12164 certified CW724R Brass rod) is sourced from European and Indian certified mills with full EN 10204 3.1 certification. Incoming material is verified by XRF spectrometer (Olympus Delta) for alloy composition and by hardness testing. CNC turning is performed on Swiss-type lathes (Citizen L-series, Star SB series) for diameters 1–32 mm and on CNC turning centres (Mazak Quick Turn, DMG MORI) for larger diameters. Secondary operations include CNC milling, drilling, tapping, reaming, broaching, and knurling. Thread inspection is carried out with calibrated go/no-go thread gauges per ISO 1502. Dimensional inspection uses CMM (Mitutoyo Crysta-Apex) with full GD&T verification. Parts are cleaned ultrasonically, passivated or plated per specification, and packed in moisture-barrier polybags with desiccant for international export.
Quality Standards and Certifications
| Standard / Certification | Scope |
|---|---|
| ISO 9001:2015 | Quality Management System |
| EN 12164 / EN 12167 | CW724R Brass rod and bar |
| RoHS 2 (2011/65/EU) | Lead-free compliance (<0.09% Pb) |
| REACH (1907/2006/EC) | No SVHC above threshold |
| NSF/ANSI 61 | Potable water contact |
| EN 10204 3.1 | Material test certificates |
| ISO 286-1 | Dimensional tolerance system |
| ISO 9227 | Salt spray corrosion test |
Why Choose Electrical Accessories India for CW724R Lead Free Brass Machined Parts
With over two decades of precision machining experience, Electrical Accessories India is a trusted supplier of CW724R Lead Free Brass components to electrical OEMs, EPC contractors, and power utilities across Europe, the Middle East, Africa, Southeast Asia, and the Americas. Our integrated facility combines in-house raw material verification, multi-axis CNC machining, plating, and quality inspection under one roof, ensuring faster lead times (typically 3–6 weeks for new parts), competitive pricing at US$ 11.50/kg, and consistent conformance to customer drawings. We hold ISO 9001:2015 certification, provide full RoHS/REACH documentation, and offer technical support for alloy selection, design-for-manufacturability (DFM), and substitute material recommendations.
Frequently Asked Questions (FAQ)
What is CW724R Brass?
CW724R is the EN (European Norm) designation for the Brass alloy CuZn21Si3P — a lead-free, silicon-modified Brass containing approximately 75–77% Copper, 21% Zinc, 3% Silicon, and trace Phosphorus, with lead content limited to 0.09% maximum.
Is CW724R RoHS compliant?
Yes. CW724R (CuZn21Si3P) contains less than 0.09% lead by weight, well within the 4% exemption threshold for Copper alloys under RoHS 2 Annex III (and even below the stricter 0.1% threshold for most electrical equipment). It is fully compliant with RoHS 2, REACH, and ELV Directives.
What is the machinability of CW724R compared to free-cutting Brass (CW614N)?
CW724R has a machinability index of approximately 70% relative to CW614N (CuZn39Pb3) rated at 100%. With optimised carbide tooling, cutting fluid, and programming, CNC cycle times are typically 20–30% longer than for leaded Brass, while achieving superior corrosion resistance and regulatory compliance.
What is the price of CW724R Lead Free Brass machined parts?
Our ex-works India price is US$ 11.50 per kilogram for standard machined parts, subject to order volume, part complexity, and surface finish requirements. Please contact us for a formal quotation.
Can CW724R parts be used in drinking water (potable water) applications?
Yes. CW724R is approved for potable water contact under NSF/ANSI 61, EN 15664-1 (Brass for water contact), and WRAS (UK Water Regulations Advisory Scheme). Its lead content of <0.09% satisfies the strictest international standards for water-contact Brass components.
What surface finishes are available?
We supply CW724R machined parts as-machined, bright polished, nickel plated (EN/ISO 1456), tin plated, silver plated, or with chromate passivation. Custom surface treatments are available on request for specific corrosion or conductivity requirements.
What is the minimum order quantity (MOQ)?
Standard MOQ is 500 pieces per part number. For high-volume CNC production runs (≥10,000 pcs), preferential pricing and dedicated production slots are available.
Which industries require CW724R Lead Free Brass machined parts?
Key sectors include electrical switchgear OEMs, EPC contractors, potable water plumbing systems, automotive (ELV-compliant), HVAC, oil & gas instrumentation, marine, and renewable energy installations in regions mandating lead-free Copper alloys.
Do you export CW724R machined parts?
Yes. We export to over 40 countries including Germany, UK, Netherlands, USA, UAE, Saudi Arabia, South Africa, Australia, and Singapore. All export shipments are accompanied by EN 10204 3.1 MTC, RoHS declaration, and country-specific compliance documentation.
What is the lead time for custom CW724R machined parts?
Typical lead time for new custom parts is 3–6 weeks from approved drawing, including first article inspection (FAI) and PPAP documentation if required.
International Terms and Equivalents
| Language | Equivalent Terms |
|---|---|
| Spanish (Español) | Latón sin plomo CW724R, Piezas mecanizadas de latón libre de plomo, Latón CuZn21Si3P |
| Russian (Русский) | Безсвинцовая латунь CW724R, Обрабатываемые детали из латуни без свинца, Латунь CuZn21Si3P |
| French (Français) | Laiton sans plomb CW724R, Pièces usinées en laiton sans plomb, Laiton CuZn21Si3P |
| Portuguese (Português) | Latão sem chumbo CW724R, Peças usinadas de latão livre de chumbo, Latão CuZn21Si3P |
| Italian (Italiano) | Ottone senza piombo CW724R, Parti lavorate in ottone senza piombo, Ottone CuZn21Si3P |
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Request a Quote – CW724R Lead Free Brass Machined Parts
Electrical Accessories India – Your trusted manufacturer of CW724R (CuZn21Si3P) Lead Free Brass machined components. Supply ex-works India at US$ 11.50/kg. ISO 9001:2015 certified. RoHS / REACH / NSF compliant. Exporting to 40+ countries.
Contact us today with your drawing, specification, or part number for a competitive quotation. Email: Contact Form | Back to Stamped & Machined Parts
