In the demanding landscape of high-performance metallurgy, UNS C14700 Sulfur Copper (popularly referred to as free-machining sulfur copper or ASTM B301 alloy) stands as an engineering marvel. Combining the exceptional electrical and thermal conductivity of pure copper with the high machinability indices typically reserved for free-cutting brass, C14700 offers a balanced option for high-throughput electrical, electronic, and industrial thermal management assemblies.
Historically, engineers faced a stark trade-off: choose pure copper (C11000/C10200) for ultimate conductivity at the expense of tool wear and slow production cycles, or opt for leaded brasses, sacrificing up to 70% of the raw electrical conductivity. By incorporating carefully regulated sulfur particulates into the copper matrix, Sichuan Kepai New Material Co., Ltd. produces C14700 sulfur copper that delivers a machinability rating of 85% compared to free-cutting brass, while retaining over 90% IACS electrical conductivity.
As a premier high-tech metallurgy enterprise established in 2017, Sichuan Kepai operates a state-of-the-art facility spanning 9,000 square meters. Our R&D and engineering teams leverage advanced continuous casting and specialized drawing processes to produce C14700 rods, wires, plates, and customized profiles. We adhere to rigid metallurgical quality protocols to guarantee consistency, satisfying the highest standards of international procurement managers.
| Alloy Grade | Copper (Cu) Min % | Sulfur (S) % | Phosphorus (P) % | Electrical Conductivity (% IACS) | Machinability Rating (Relative to Brass) |
|---|---|---|---|---|---|
| UNS C14700 / ASTM B301 | 99.0% | 0.20% - 0.50% | 0.003% - 0.012% | 90% - 95% | 85% |
| UNS C14500 (Tellurium Copper) | 99.5% | - | 0.004% - 0.012% (Te: 0.4-0.7%) | 90% - 98% | 85% |
| UNS C11000 (ETP Copper) | 99.9% | - | - | 101% | 20% |
Exploring the macro trends driving the adoption of high-conductivity free-machining alloys across global industrial hubs.
Global initiatives like Europe’s RoHS Directive and REACH are enforcing strict caps on hazardous heavy metals, particularly lead. C14700 Sulfur Copper acts as a key compliant alternative to leaded coppers (such as C18700), offering highly comparable high-speed machining tolerances without risking regulatory non-compliance in consumer electronics, automotive sensor hubs, or semiconductor testing fixtures.
The expansion of electric vehicles (EVs), grid-scale energy storage, and 5G base stations has created a surging demand for components that can handle huge electrical currents while remaining cost-effective to produce. From electrical relay terminals to high-current connectors and electric vehicle charging points, C14700 minimizes electrical losses while supporting high-volume automated Swiss lathe production.
In modern laser-cutting heads, gas-shielded plasma torches, and aerospace cooling apparatuses, components face high thermal stress. C14700’s high thermal conductivity ensures effective heat dissipation, while its unique metallurgical formulation prevents chip wrapping during high-speed CNC turning, thereby reducing tool breakage and downtime.
Delivering high performance in specialized environments across major localized markets worldwide.
North American EV Infrastructure: In the United States and Canada, custom C14700 sulfur copper pins are utilized extensively inside Level 3 DC Fast Chargers. High conductivity prevents localized overheating, while the alloy's structural integrity resists fatigue over thousands of mating cycles.
European Automated Distribution: European grid switchgear and automation hubs integrate C14700 connectors due to the alloy’s excellent resistance to atmospheric corrosion. Its low susceptibility to hydrogen embrittlement makes it suitable for complex hermetically sealed gas-insulated systems.
Asia-Pacific Semiconductor Testing: Precision-machined micro-pins and probe tips in Japan, South Korea, and Taiwan rely on C14700. The fine, uniform dispersion of sulfur precipitates guarantees that sub-millimeter components can be turned with micron-level precision and without burrs.
Integrating state-of-the-art metallurgy, extrusion, drawing, and multi-tier testing systems to guarantee a zero-defect supply chain.
Leveraging localized advantages and vertically integrated production to offer high-quality copper alloys globally.
Established in 2017, Sichuan Kepai New Material Co., Ltd. is an integrated R&D, production, and sales enterprise specializing in premium copper alloys. Operating a 9,000 square meter factory alongside 1,000 square meters of high-tech research offices, our facilities are located in the Western Area of the Sichuan Guanghan Industrial Development Zone. Positioned adjacent to National Highway 108, we benefit from convenient logistics that connect our plant directly to international shipping hubs.
By controlling every stage of production—from raw copper cathode melting and precise sulfur alloying to heavy extrusion, cold drawing, and multi-axial straightening—we bypass supply vulnerabilities that affect other fabricators. Our integrated business model allows us to offer shorter lead times, custom chemistry options, and consistent, traceable quality for OEM projects of any scale.
In addition to C14700 Sulfur Copper, our high-performance product range includes tellurium copper, chromium zirconium copper, high-conductivity oxygen-free copper, silver copper, and dispersion-strengthened copper. We design materials for demanding high-tech applications, including new energy vehicles, 5G communications, laser-cutting optics, and lithium battery relays.
Exploring the metallurgical technologies and process refinements driving the future of high-conductivity alloys.
We are integrating AI-based thermodynamic modeling to optimize the dispersion of sulfur phase particles. This allows us to control the size and distribution of copper sulfide inclusions down to sub-micron scales, improving chip fragmentation during CNC milling while preserving electrical conductivity.
In response to the miniaturization of 5G connectors and micro-relays, our team is developing ultra-fine C14700 wire drawing processes. By refining die geometry and lubrication systems, we aim to produce consistent sulfur copper wires under 0.5 mm in diameter, maintaining high surface finish and tensile strength.
We are upgrading our induction furnaces to reduce carbon emissions and minimize energy consumption per ton of copper alloy produced. Through refined sorting and melting of C14700 production scrap, we support circular economy initiatives, helping global procurement partners meet their scope 3 emissions targets.
Every batch of our special copper alloys is fully certified, traceable, and compliant with international industrial standards.
Operating in international industrial supply chains requires rigorous compliance and documentation. Sichuan Kepai maintains an ISO 9001:2015 certified quality management system. Our C14700 Sulfur Copper alloys are accompanied by comprehensive chemical and physical mill test reports (MTRs), including optical emission spectrometry (OES) analyses and eddy current integrity reports.
We ensure strict compliance with the EU RoHS directive (2011/65/EU and amendment 2015/863) and REACH regulations. By choosing Kepai's sulfur copper, you receive high-performance machining alloys that meet international environmental standards, securing a hassle-free import process and safe application in consumer products.
Expert metallurgical answers regarding specifications, processing, compliance, and custom ordering.
Both C14700 and C14500 are high-conductivity, free-machining copper alloys sharing a machinability index of 85% and electrical conductivity exceeding 90% IACS. The primary distinction lies in their alloying elements. C14700 incorporates sulfur (0.20-0.50%), while C14500 contains tellurium (0.40-0.70%). C14700 often serves as a cost-effective alternative to tellurium copper in applications like electrical connectors and gas cutting nozzles, where tellurium's slightly higher raw material cost is a factor.
Yes. C14700 does not contain added lead, cadmium, or mercury. The sulfur addition is not restricted by RoHS or REACH directives, making C14700 a compliant option for replacing lead-bearing free-cutting coppers (such as C18700 or leaded brasses) in electronic components exported to the European Union and North America.
Pure copper is highly ductile and gummy, which leads to long, continuous chips that wrap around cutting tools, increasing wear and heat. During the smelting process of C14700, sulfur reacts to form fine, insoluble copper sulfide (Cu2S) particles that disperse evenly throughout the copper matrix. These particles act as natural chip-breakers, causing the chips to shear easily. They also provide localized lubrication, extending tool life and enabling high cutting speeds.
C14700 has excellent soft soldering characteristics and good silver-brazing capability. However, caution is required during high-temperature gas-shielded arc welding. The presence of sulfur can induce hot-shortness (cracking during solidification) in large-scale weld pools. For joining processes, brazing or soldering is generally recommended over traditional fusion welding.
Sichuan Kepai provides C14700 sulfur copper in a wide variety of formats, including round bars, hexagonal rods, square rods, wires, plates, and customized extruded profiles. Utilizing advanced cold-drawing and straightening equipment, we achieve tight dimensional tolerances (up to h9 or h8 class) and high straightness, ensuring compatibility with high-speed automated Swiss screw machines.
Lead times depend on the complexity of the profiles and order volumes. For standard rounds and hex bars, we maintain a baseline stock that allows dispatch within 7-10 working days. For custom profiles, specialized alloy compositions, or custom temper requirements, the typical production window spans 20-30 days from engineering drawing approval. This timeline is supported by our vertically integrated manufacturing facility in Guanghan.
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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