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A comprehensive technical analysis of chemical compositions, mechanical characteristics, and global standards compliance.
C54400 phosphor bronze, widely referenced in global manufacturing under UNS C54400 and EN standards as CuSn4Zn4Pb4, is widely acclaimed as the premier free-cutting phosphor bronze alloy. By incorporating precise trace additions of lead (Pb) and zinc (Zn) into the primary copper-tin matrix, C54400 achieves an exceptional machinability rating of 80% (relative to Free-Cutting Brass C36000 rated at 100%). This metallurgical formulation creates a metal matrix characterized by high fatigue strength, phenomenal wear and friction properties, and excellent electrical and thermal conductivity.
From a technical standpoint, the tin content (typically 3.5% to 4.5%) enhances the alloy's tensile strength and corrosion resistance, while the zinc content (3.5% to 4.5%) aids in deoxidization and cold-workability. The lead content (3.5% to 4.5%) acts as an internal lubricant and chip breaker, which substantially reduces tool wear during high-speed CNC Swiss-turning operations. This unique synergy makes C54400 bronze bars the go-to standard for bushings, bearings, gear shafts, electrical connectors, and marine hardware components.
To assist global procurement engineers in material selection, the table below highlights the performance, composition, and processing parameters of C54400 relative to alternative industrial alloys.
| Alloy Grade | Composition (Nominal) | Machinability Index | Tensile Strength (MPa) | Yield Strength (MPa) | Key Applications |
|---|---|---|---|---|---|
| UNS C54400 | Cu (Bal), Sn (4%), Zn (4%), Pb (4%), P (0.01-0.35%) | 80% | 340 - 520 | 170 - 450 | Bushings, electrical spring pins, gears, precision shafts |
| UNS C51000 | Cu (Bal), Sn (5%), P (0.2%) | 20% | 330 - 620 | 130 - 550 | High strength springs, diaphragms, bellows |
| UNS C36000 | Cu (61.5%), Pb (3%), Zn (Bal) | 100% | 340 - 470 | 120 - 310 | High-volume hardware, valves, fittings |
In mature manufacturing zones, C54400 bronze bars play a vital role in heavy and light engineering applications. Here are the primary localized applications:
As modern regulatory environments tighten restrictions on heavy metals, purchasing C54400 requires careful scrutiny of material chemical certification records. Reliable manufacturers provide comprehensive material testing certifications, ensuring that although lead is included to optimize machining characteristics, it strictly conforms to regional compliance exceptions (such as RoHS Annex exemptions for lead in copper alloys under category 6c). Additionally, our manufacturing processes comply with international quality guidelines, ensuring that our products meet ASTM B139/B139M, JIS H3250, and BS EN 12164 standards, giving global engineering teams absolute confidence in raw material reliability.
China's Leading Innovator in High-Conductivity, High-Strength special copper alloys.
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.
Verified international quality, management system compliance, and product safety test report clearances.
We leverage top-tier metallurgical machinery and high-precision inspection tools to guarantee absolute batch-to-batch consistency.
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
Addressing engineering specifications, sourcing questions, compliance guidelines, and procurement terms.
A: C54400 contains a specific addition of lead (about 4%), which disperses uniformly through the copper-tin matrix. This lead acts as a natural lubricant that significantly reduces friction and wear between metal parts. When coupled with tin's strength and corrosion resistance, it enables bearings to handle heavy loads, resist galling, and work reliably under marginal lubrication conditions.
A: Although C54400 contains lead, it qualifies under specific exemptions (such as European RoHS Annex III Exemption 6c, which permits lead as an alloying element in copper up to 4% by weight). We conduct strict optical emission spectrometry (OES) testing on every batch to guarantee that the lead levels do not exceed the permitted limits and provide full compliance documents for import clearance.
A: Sourcing from Chinese manufacturers like Sichuan Kepai gives you access to a fully integrated supply chain, from smelting and hot extrusion to final drawing and polishing. This end-to-end management, combined with our location near major transport links like National Highway 108, keeps production costs low, guarantees quality control, and ensures shorter lead times for custom orders.
A: Welding C54400 is generally not recommended due to the high lead content, which can lead to hot-shortness and structural porosity during cooling. However, brazing and soldering are excellent and highly reliable methods for joining this alloy, provided you clean the joint properly and use the right fluxing agent.
A: MOQs depend on the exact profile dimensions and grade requirements. For standard round bars, the MOQ is typically lower, while custom-extruded or drawn profiles may require larger orders to cover set-up costs. Lead times generally range between 15 to 35 days, including complete quality testing and ocean-freight packaging.
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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