Silicon Bronze C83600 – CDA 836 Casting | Leaded Red Brass Sand & Investment Castings

Silicon Bronze C83600 – CDA 836 Casting | Leaded Red Brass Sand & Investment Castings

Silicon Bronze C83600 (CDA 836), also known as Leaded Red Brass or 85-5-5-5 bronze, is one of the most widely specified copper-base casting alloys in industrial and electrical engineering. Electrical Accessories India manufactures precision sand castings, investment castings, and machined components in C83600 / CDA 836 alloy for electrical OEMs, EPC contractors, power utilities, and industrial distributors worldwide. With a nominal composition of 85% copper, 5% tin, 5% lead, and 5% zinc, this alloy delivers an optimal balance of pressure tightness, machinability, corrosion resistance, and bearing properties that make it the standard choice for valve bodies, pump housings, connectors, and electrical hardware across multiple industries. Indicative price: US$ 13.90/kilogram (subject to quantity and specification).

Product Overview

Alloy Composition and Metallurgical Characteristics

C83600 is a quaternary copper-tin-lead-zinc alloy governed under ASTM B584, ASTM B62, and SAE J461 standards. The alloy’s 85% copper matrix provides the foundational corrosion resistance, while tin additions (4.0–6.0%) enhance strength and hardness. Lead (4.0–6.0%) improves machinability and provides natural lubrication in bearing applications. Zinc (4.0–6.0%) acts as a deoxidizer and improves casting fluidity. The resulting microstructure consists of an alpha-copper solid solution with lead and tin-intermetallic phases, yielding a Brinell hardness of 60–65 HB, tensile strength of 241 MPa, and elongation of 20%. The alloy exhibits excellent pressure tightness, making it the preferred material for hydraulic and pneumatic valve castings, pipe fittings, and fluid-handling components. CDA 836 castings maintain dimensional stability across temperature ranges from cryogenic to approximately 260°C, suitable for steam and thermal-fluid service.

Casting Process Suitability

C83600 demonstrates excellent castability across all major foundry processes: green sand casting, no-bake sand casting, lost wax (investment casting), shell mold casting, and permanent mold casting. The alloy’s relatively low melting range (852–1010°C) and good fluidity allow it to fill complex thin-section geometries without hot-tearing or misrun defects. Its lead content ensures minimal die sticking in permanent mold processes. Wall thicknesses from 3 mm to over 100 mm are achievable with consistent mechanical property uniformity. Post-cast heat treatment is generally not required, though stress relieving at 260°C is applied when dimensional stability is critical in precision machined valve seats, gland bushings, and terminal blocks.

Pressure Tightness and Fluid-Handling Applications

The pressure tightness of CDA 836 castings—verified under ASTM B62 hydrostatic test protocols—makes this alloy the standard material for water works valves, gate valves, globe valves, and check valves per AWWA C800 and MSS SP-80 standards. The alloy’s resistance to dezincification (due to low zinc content <8%) eliminates the need for DZR-grade brass in most potable water applications. C83600 castings maintain integrity under operating pressures up to 300 psi (20.7 bar) for water, gas, and steam service, making them suitable for plumbing manifolds, steam traps, pressure gauge bodies, and hydraulic cylinder end caps used in industrial machinery and process piping.

Corrosion Resistance and Marine Environment Performance

The high copper content (85%) of C83600 provides inherent resistance to seawater corrosion, salt-spray attack, and biofouling, making CDA 836 castings extensively used in marine hardware, shipboard fittings, pump impellers, and offshore electrical enclosure components. The alloy resists attack by dilute acids, organic solvents, and neutral saline environments, maintaining protective copper-oxide surface patina without surface treatment in most marine-grade applications. For underground and buried service (cable gland bodies, earth pit covers, grounding connector housings), C83600 castings outperform standard brass and steel in soil corrosion resistance, particularly in chloride-rich soils common in coastal and industrial environments.

Machinability and Post-Cast Processing

With a machinability rating of 90% relative to free-cutting brass (C36000 = 100%), C83600 is one of the most easily machined copper-base casting alloys available. Lead acts as a chip-breaker and coolant during turning, milling, drilling, reaming, and tapping operations, enabling high production rates on CNC lathes and machining centers. Surface finishes of Ra 0.8–1.6 µm are achievable without specialist tooling. Secondary operations including thread cutting, knurling, broaching, and internal grinding are routinely performed. The alloy accepts electroplating (nickel, tin, chrome), powder coating, and chemical passivation treatments. Electrical Accessories India offers fully machined-to-drawing CDA 836 castings with critical dimensions held to ISO 2768-m tolerances as standard.

Electrical Conductivity and Hardware Applications

C83600 exhibits electrical conductivity of approximately 15% IACS (International Annealed Copper Standard), sufficient for current-carrying electrical hardware where mechanical strength, thread integrity, and corrosion resistance are primary requirements alongside moderate conductivity. Applications include cable gland bodies, compression gland nuts, electrical terminal blocks, earthing clamps, neutral link housings, distribution board components, switchgear casting parts, and busbar support brackets. The alloy’s non-sparking nature and non-magnetic properties are additional engineering advantages in hazardous area electrical installations (ATEX/IECEx zones) and in proximity to sensitive magnetic equipment.

Bearing and Wear-Resistant Applications

The lead phase in C83600 provides a natural solid lubricant matrix, making CDA 836 castings suitable for sleeve bearings, bushing, thrust washers, and wear plates operating at moderate loads and speeds (PV value up to 50,000 psi·ft/min). The alloy outperforms oil-impregnated sintered bronze in conditions where contamination or interrupted lubrication is possible. C83600 cast bushings are used in pump bearing housings, conveyor systems, agricultural machinery, and construction equipment. When used as mating surfaces against steel shafts, CDA 836 provides excellent compatibility with surface hardnesses of 25–55 HRC, minimizing shaft scoring during boundary lubrication conditions common at startup and shutdown.

Key Features of C83600 / CDA 836 Bronze Castings

• Composition: Cu 85%, Sn 5%, Pb 5%, Zn 5% (ASTM B584 / UNS C83600)
• Excellent pressure tightness — suitable for hydraulic, pneumatic, and steam service
• High machinability rating (90% of free-cutting brass)
• Outstanding corrosion resistance in marine, potable water, and industrial environments
• Non-sparking, non-magnetic — suitable for ATEX/IECEx hazardous area applications
• Available in sand casting, investment casting, permanent mold, and machined forms
• Compliant with ASTM B62, ASTM B584, SAE J461, EN 1982 CC491K standards
• Custom castings per customer drawings with ISO 2768-m dimensional tolerances

Pressure Integrity and Leak-Free Performance

All C83600 castings from Electrical Accessories India undergo pneumatic or hydrostatic pressure testing per ASTM B62 or customer-specific protocols. The alloy’s inherent porosity-free microstructure (when processed under controlled foundry conditions) ensures leak-free performance in valve bodies, pump casings, manifold blocks, and hydraulic cylinder housings. Radiographic and dye-penetrant inspection services are available for critical-service applications in oil and gas, power generation, and water treatment infrastructure.

Thread and Fastener Compatibility

C83600 castings accept BSP, NPT, BSPT, metric ISO 228, and UNC/UNF threaded inserts and tapped holes with excellent thread-form quality due to the alloy’s low work-hardening rate and free-cutting characteristics. The material supports Whitworth, unified, and metric thread standards, making CDA 836 cast components directly interchangeable with OEM brass and bronze parts in fluid systems, cable management hardware, and electrical distribution equipment. Thread pull-out strength in C83600 exceeds minimum ASME B1.20.1 requirements for all standard pipe thread engagements.

Surface Finishing and Coating Options

CDA 836 bronze castings are supplied in as-cast, machined, tumble-deburred, or electroplated conditions per customer requirements. Standard finishing options include bright tin plating (5–10 µm per IEC 60068-2-58), nickel plating for elevated temperature service, chrome plating for decorative and corrosion applications, and chemical passivation per MIL-DTL-45204 for enhanced oxide resistance. Shot blasting (Sa 2.5 per ISO 8501-1) and vibratory finishing are available for surface preparation prior to painting or special coating in architectural and structural applications.

Weight Optimization and Design Flexibility

Electrical Accessories India offers DFM (Design for Manufacturability) consultation to optimize C83600 casting geometry for weight reduction while maintaining structural integrity. FEA-assisted wall thickness optimization, coring strategies, and parting line design minimization are offered as value-added engineering services, reducing material cost and post-machining time. Rapid prototyping using 3D-printed sand molds enables first-article samples within 10–15 working days, supporting fast product development cycles for OEM electrical and industrial hardware programs.

Export Compliance and International Standards

All CDA 836 castings are supplied with material test reports (MTR) per EN 10204 3.1 certification, chemical composition certificates, mechanical property test results, and dimensional inspection reports. Export documentation includes country of origin certificates, REACH compliance declarations (RoHS directive), and MSDS/SDS sheets. The alloy complies with EU Drinking Water Directive 98/83/EC (third-party tested) for potable water contact applications and California Proposition 65 lead content disclosure requirements for US market supply.

Technical Specifications

International Equivalent Grades

Product Types and Variants

• Sand Castings: Valve bodies, pump casings, cable gland housings, manifold blocks, plumbing fittings
• Investment Castings: Complex precision components, impellers, small valve internals, electrical connectors
• Permanent Mold Castings: High-volume production of bushings, flanges, terminal blocks
• Machined Castings: Fully CNC-machined to drawing, threaded, bored, and reamed components
• Custom Castings: Per customer 2D drawing or 3D CAD model (STP/IGS format accepted)

Applications by Industry

Manufacturing Process

Electrical Accessories India produces C83600 / CDA 836 castings using ISO 9001:2015-compliant foundry processes. Raw material procurement is from certified suppliers with mill certificate traceability. Charge composition is verified by OES (Optical Emission Spectrometry) prior to melt. Induction furnace melting ensures uniform alloy distribution and controlled degassing. Mold preparation follows established pattern/tooling qualification procedures. Pouring temperature is controlled within ±10°C of specification to prevent porosity and ensure consistent mechanical properties. After solidification and shakeout, castings undergo fettling (gate/riser removal), shot blasting, dimensional inspection per drawing, and optional CNC machining. Final inspection includes visual, dimensional (CMM for critical parts), pressure testing, and MTR preparation before dispatch.

Quality Standards and Certifications

• ISO 9001:2015 – Quality Management System
• ASTM B584 – Standard Specification for Copper Alloy Sand Castings for General Applications
• ASTM B62 – Standard Specification for Composition Bronze (UNS C83600)
• EN 1982 – Copper and copper alloys: Castings (CC491K)
• SAE J461 – Wrought and Cast Copper Alloys
• EN 10204 Type 3.1 – Material Test Reports available
• RoHS / REACH compliance documentation available
• BS EN ISO 2768-m – General dimensional tolerances

Why Choose Electrical Accessories India for C83600 Castings

Electrical Accessories India combines over two decades of foundry and precision machining experience with a dedicated focus on copper-alloy castings for the electrical and industrial sectors. Our in-house metallurgical laboratory, ISO 9001:2015 certification, and direct export capability to over 40 countries ensure consistent quality and reliable delivery. We offer competitive pricing, small-to-large batch flexibility, EN 10204 3.1 material certifications, custom machining to drawing, and responsive technical support for OEM development programs. Our team provides alloy selection guidance, DFM review, and application engineering support to help customers optimize component performance and lifecycle cost.

Frequently Asked Questions – C83600 / CDA 836 Casting

Q1: What is the difference between C83600 and C84400 bronze?

C83600 (85-5-5-5) contains 85% Cu, 5% Sn, 5% Pb, 5% Zn. C84400 (81-3-7-9) has lower copper and tin with higher zinc, resulting in slightly lower corrosion resistance. C83600 is preferred for pressure-critical and marine applications.

Q2: Is C83600 the same as LG2 gunmetal?

Yes. LG2 (BS 1400 designation) and C83600/CC491K are nominally equivalent alloys — both describe the 85-5-5-5 leaded red brass/gunmetal composition. Minor composition tolerances differ between standards.

Q3: What casting processes can produce C83600 parts?

C83600 is compatible with green sand, no-bake sand, investment, shell mold, and permanent mold casting processes. Process selection depends on required dimensional tolerance, surface finish, production volume, and component complexity.

Q4: What is the maximum pressure rating for CDA 836 valve castings?

Per ASTM B62, C83600 valve castings are rated for up to 300 psi (20.7 bar) for water/gas service at ambient temperature. Ratings decrease with temperature per ASME B16.44 and MSS SP-80 pressure-temperature tables.

Q5: Does C83600 comply with lead-free regulations for potable water?

Standard C83600 contains 4–6% lead and does NOT comply with US Safe Drinking Water Act lead-free requirements (<0.25% weighted average). For potable water in USA/Canada, consider C89833 (BiLead™) or lead-free bronze alternatives. EU DWD compliance varies by member state.

Q6: What is the minimum order quantity for custom C83600 castings?

Minimum order quantities start from 50 kg for sand castings and 25 kg for investment castings. Tooling/pattern charges apply for new designs; existing tooled designs carry no tooling surcharge.

Q7: What dimensional tolerances are standard for C83600 sand castings?

Standard sand casting tolerances follow ISO 8062 CT8–CT10 (General) or ASTM B584 Annex. Machined features are held to ISO 2768-m (±0.1 mm on features up to 30 mm) as standard; tighter tolerances available on request.

Q8: Can you supply material test reports (MTR) with C83600 castings?

Yes. EN 10204 Type 3.1 material test reports covering chemical composition (OES analysis) and mechanical properties (tensile, hardness) are provided as standard with all export orders.

Q9: What is the lead time for C83600 castings from Electrical Accessories India?

Standard lead time is 3–5 weeks for production quantities from established tooling. First articles for new tooling require 6–8 weeks including pattern fabrication, first pour, inspection, and customer approval.

Q10: What are the equivalent terms for C83600 in other languages?

See the multilingual equivalents section below.

Multilingual Equivalent Terms

Related Products and Linked Terms

• Silicon Bronze Castings (C87300, C87600, CC212A)
• LG2 Gunmetal Casting
• 85-5-5-5 Bronze Alloy Casting
• C83600 Casting / CDA 836 Casting
• Brass Castings
• Phosphor Bronze Casting and Machined Parts
• Aluminum Bronze Casting
• Related Terms: Leaded red brass casting, composition bronze casting, 85-5-5-5 alloy, ASTM B62 casting, CC491K casting, RG5 Rotguss, CAC406 bronze, gunmetal casting India, pressure-tight bronze casting, CDA 836 export

Request a Quote – C83600 / CDA 836 Bronze Castings

Electrical Accessories India is a leading manufacturer and exporter of C83600 / CDA 836 leaded red brass castings. Send us your drawing (PDF, DWG, STP) or part specification for a competitive quotation within 24 hours.

Indicative Price: US$ 13.90/kilogram (FOB India, subject to alloy composition verification, quantity, and specification. Contact us for exact pricing.)

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