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Explore our high-performance copper alloy materials optimized for precision machining applications
A definitive overview of the alloy that defines modern precision machining
C18700 Leaded Copper is a high-purity copper alloy containing approximately 0.8–1.5% lead, specifically engineered to dramatically improve machinability while retaining the outstanding electrical and thermal conductivity inherent to copper. Classified under the UNS (Unified Numbering System) as C18700, this alloy is sometimes referred to as "free-machining copper" or "leaded copper," and it stands as one of the most widely utilized copper grades in the global precision parts manufacturing industry.
C18700 Leaded Copper holds a machinability rating of 100% — the benchmark against which all other copper alloys and many other metals are measured. This makes it the go-to material for high-volume, high-speed CNC machining operations where tool life, surface finish, and dimensional accuracy are paramount.
The addition of lead to copper creates a microstructure where fine lead particles are dispersed throughout the copper matrix. During machining, these particles act as internal lubricants and chip-breakers, allowing cutting tools to glide through the material with minimal resistance. The result is a dramatically reduced cutting force, lower heat generation, extended tool life, and superior surface finishes — all critical factors in the production of precision components.
Beyond machinability, C18700 retains electrical conductivity typically above 96% IACS (International Annealed Copper Standard), making it uniquely suited for components that must simultaneously function as precision-machined mechanical parts and electrical conductors. This dual-performance capability is rare among engineering materials and positions C18700 as an indispensable alloy across multiple high-technology industries.
Understanding the technical foundation that makes this alloy exceptional for precision machining
Maintains ≥96% IACS electrical conductivity, ensuring excellent performance in electronic connectors, relay contacts, and conductive precision parts where signal integrity is critical.
The industry benchmark for machinability. Lead particles embedded in the copper matrix act as chip-breakers, enabling ultra-high-speed CNC turning, drilling, and milling with minimal tool wear.
Thermal conductivity of approximately 339 W/m·K — ideal for heat sinks, thermal management components, and parts requiring rapid heat dissipation in high-power applications.
Excellent dimensional stability during and after machining, ensuring tight tolerances (±0.005mm or better) are maintained — essential for aerospace, medical, and semiconductor components.
Good resistance to atmospheric corrosion and many industrial chemicals. Can be further enhanced through plating (nickel, tin, silver) for demanding environments.
Achieves mirror-like surface finishes (Ra ≤ 0.4 μm) directly from machining without additional grinding or polishing, significantly reducing post-processing time and cost.
C18700 Leaded Copper in the global precision manufacturing landscape
The global market for free-machining copper alloys, led by C18700, has demonstrated consistent growth over the past decade. Driven by accelerating demand from the automotive, electronics, telecommunications, and aerospace sectors, the precision copper components market was valued at over USD 4.2 billion in 2023 and is projected to grow at a CAGR of approximately 5.8% through 2030. Asia-Pacific — particularly China, Japan, and South Korea — accounts for the largest share of consumption, fueled by the rapid expansion of EV manufacturing, 5G infrastructure deployment, and consumer electronics production.
The global transition to electric vehicles (EVs) represents one of the most significant demand drivers for C18700 Leaded Copper. Each electric vehicle contains hundreds of precision-machined copper components — from motor terminal connectors and battery management system contacts to charging port components and power distribution units. The superior machinability of C18700 allows manufacturers to produce these components at the volumes and tolerances required by EV production lines operating at automotive-grade quality standards. As global EV sales are projected to exceed 45 million units annually by 2030, demand for high-machinability copper alloys is set to surge correspondingly.
The global rollout of 5G networks has created unprecedented demand for precision copper components in base stations, RF connectors, antenna systems, and semiconductor test equipment. C18700's combination of near-perfect electrical conductivity and exceptional machinability makes it the preferred material for these high-frequency, tight-tolerance applications. As 5G transitions to 6G research and millimeter-wave applications become mainstream, the requirements for precision and conductivity will only intensify — further cementing C18700's market position.
Environmental regulations (RoHS, REACH) have prompted research into lead-free alternatives such as tellurium copper (C14500) and sulfur copper (C14700). However, C18700 continues to dominate in applications exempt from lead restrictions — including industrial machinery, plumbing, and non-consumer-facing precision parts — due to its unmatched machinability economics. The strategic use of C18700 in compliant applications remains a cornerstone of competitive precision manufacturing.
The rise of Industry 4.0 — characterized by smart factories, AI-driven CNC machining, and digital twin technology — has amplified the advantages of C18700. In automated, high-speed machining environments where tool changes must be minimized and cycle times optimized, C18700's predictable chip formation and consistent material properties translate directly into higher OEE (Overall Equipment Effectiveness) scores. Leading manufacturers are now integrating C18700 material data into digital twin models to simulate and optimize machining parameters before production begins, reducing scrap rates to below 0.5%.
Where C18700 Leaded Copper delivers transformative value in precision machined parts
C18700 is extensively used for machining EV motor terminal pins, battery pack busbars, high-voltage connector housings, and charging interface contacts. Its high conductivity minimizes resistive losses in power circuits, while its machinability enables the micro-tolerance geometries required by modern automotive assembly robots. Tier-1 automotive suppliers rely on C18700 for components requiring IPC Class 3 reliability standards.
In 5G base station infrastructure, C18700 is the material of choice for SMA, N-type, and custom RF connector bodies, waveguide components, and precision antenna mounting hardware. The alloy's dimensional stability under thermal cycling — critical in outdoor telecom installations — combined with its ability to hold sub-micron tolerances on threaded interfaces, makes it irreplaceable in this sector.
Medical equipment manufacturers utilize C18700 for surgical instrument components, diagnostic device contacts, and implantable device connectors (where lead-free variants are required, C14500 is substituted). The alloy's biocompatible surface finish capability and sterilization resistance make it suitable for Class II medical device components requiring FDA-compliant manufacturing processes.
Aerospace applications demand materials that perform reliably across extreme temperature ranges (-55°C to +150°C). C18700 machined components are found in avionics connectors, hydraulic system fittings, gyroscope housings, and satellite communication hardware. The alloy's thermal conductivity also makes it valuable in thermal management systems for high-power aerospace electronics.
In semiconductor fabrication equipment — including wire bonding machines, wafer handlers, and test socket components — C18700 precision parts must maintain dimensional accuracy to within ±0.002mm while withstanding millions of operational cycles. The alloy's excellent wear characteristics and surface finish quality directly impact yield rates in semiconductor production lines valued at hundreds of millions of dollars.
Relay contact arms, circuit breaker components, and power distribution block terminals machined from C18700 benefit from the alloy's combination of high conductivity (minimizing contact resistance) and machinability (enabling complex contact geometries). In lithium battery management systems — a rapidly growing market — C18700 components ensure reliable switching performance across thousands of charge-discharge cycles.
Sichuan Kepai — the technology and manufacturing backbone behind premium C18700 supply
Technological innovation is the core competitiveness of Sichuan Kepai New Materials Co., Ltd. The company has a research and development and production team composed of senior industry experts who keep pace with international cutting-edge technology trends and continuously explore the unknown boundaries in the field of new copper alloy materials. Through a combination of independent research and development and industry-university-research collaboration, Kepai has made breakthrough progress in several areas, including high-performance tellurium copper, lead copper, and sulfur copper. Many of its technological achievements have reached international advanced levels and have been successfully applied in various industries such as new energy vehicles, precision machining parts, plasma cutting, relays, and energy storage, earning widespread recognition and praise in the market.
Kepai's product line is rich and diverse, covering a comprehensive range of solutions from basic materials to high-end customization. We focus on providing customers with high-performance, high-quality high-end copper alloy products, including but not limited to pure copper, oxygen-free copper, oxygen-free high-conductivity tellurium copper, nickel tellurium copper, tin bronze, beryllium copper, lead bronze, sulfur copper, and chromium zirconium copper. These products play an important role in reducing production costs and enhancing product performance due to their excellent physical and chemical properties and environmental friendliness, creating significant economic and social benefits for customers.
In the face of global market competition, Sichuan Kepai New Materials adheres to the development strategy of "rooted in Sichuan, radiating nationwide, and moving towards the world." By continuously optimizing market layout and improving the sales network, we have established a stable customer base in multiple provinces and cities across the country and have formed long-term cooperative relationships with several internationally renowned enterprises. At the same time, the company actively expands into overseas markets, participates in international competition and cooperation, and strives to promote Kepai's brand influence on the global stage.
We understand that the long-term development of an enterprise is inseparable from an excellent corporate culture. We advocate the corporate spirit of "integrity, innovation, collaboration, and win-win," encouraging employees to explore boldly and innovate courageously, while also emphasizing teamwork and talent cultivation, striving to create a harmonious, open, and inclusive work atmosphere. We believe that only by continuously pursuing excellence and creating value can we win the trust of customers and the respect of society.
The company is located in the western area of the Sichuan Guanghan Industrial Development Zone, adjacent to National Highway 108, boasting a superior geographical location and convenient transportation, which lays a solid foundation for the rapid development of the enterprise. Since its establishment, Kepai has adhered to the business philosophy of "innovation-driven development, quality wins the market," committed to providing customers with the highest quality high-end copper alloy materials, and promoting industrial upgrading and sustainable development.
State-of-the-art manufacturing and quality control infrastructure ensuring C18700 material excellence
Smelting
Laying-off
Extrusion
Drawing
Straightening
Package
Eddy Current Conductance Instrument
Chemical Composition Test Room
Metallographic Sample Polishing Machine
Microcomputer Controlled Electro-Hydraulic Servo Universal Testing Machine
Liquid Crystal Display Electronic Universal Testing Machine
Hardness Tester
Quality certifications and market distribution credentials backing every C18700 product
Sichuan Kepai New Material Co., Ltd.
Sichuan Kepai New Materials Co., Ltd., established in 2017, is a high-tech enterprise integrating research and development, production, and sales. Currently, the factory covers an area of approximately 9,000 square meters, with an office space of about 1,000 square meters. The company primarily engages in the production of strategic emerging new materials for the national 13th Five-Year Plan, including special copper alloys such as tellurium copper, high-conductivity oxygen-free copper, silver copper, and dispersion copper, while also focusing on the research and development of high-conductivity, easy-to-machine, high-strength copper alloys. The products are mainly applied in high-tech fields such as new energy vehicles, 5G technology, laser cutting, and lithium battery relays.
Looking ahead, Sichuan Kepai New Materials Co., Ltd. will continue to uphold its original intention, with even greater enthusiasm and determination, to engage in research and application in the field of new materials, contributing to the development of the new copper alloy materials industry in China and globally. We look forward to working hand in hand with friends from all walks of life to create a brilliant future together!
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