Phosphor Bronze

Springs and Fasteners: Used in precision springs, washers, and fasteners due to its excellent elasticity, fatigue strength, and corrosion resistance. Bearings and Bushings: Ideal for components that require low friction and high wear resistance under continuous motion. Electrical Connectors and Terminals: Commonly used in electrical contacts, terminals, and switch components because of its superior conductivity and resistance to fatigue. Marine Hardware: Perfect for ship propellers, pump parts, and marine fittings due to its outstanding resistance to saltwater corrosion. Industrial Gears and Worm Wheels: Employed in gears and worm wheels for machinery requiring quiet operation and high durability.

Phosphor Bronze exhibits moderate to high hardness, depending on its composition and heat treatment condition. The hardness mainly varies with the amount of tin and phosphorus present in the alloy and whether it is annealed or cold-worked. Annealed Condition: Typically ranges between 80 – 120 HB (Brinell Hardness). Cold-Worked Condition: Can reach up to 200 – 250 HB, offering excellent wear resistance. This hardness balance makes phosphor bronze strong enough for bearings, gears, and bushings, while still maintaining the ductility needed for springs and electrical components.

Annealing: Temperature: 400°C – 650°C Purpose: To soften the alloy after cold working, relieve internal stresses, and restore ductility. Cooling: Slow furnace cooling is recommended to avoid distortion or cracking. Stress Relieving: Tmperature: 250°C – 350°C Purpose: Removes residual stresses after machining or forming without altering mechanical properties significantly. Cold Working (Work Hardening): Instead of traditional hardening, phosphor bronze is hardened by cold working (rolling, drawing, or bending). This process increases strength and hardness while slightly reducing ductility. Age Hardening (Optional): Certain phosphor bronze alloys can undergo age hardening to further increase tensile strength and hardness.

Cold Working (Work Hardening): The primary method of hardening phosphor bronze. Involves mechanical deformation processes like rolling, drawing, or hammering at room temperature. This increases the dislocation density in the metal, improving hardness, strength, and wear resistance. The more it is worked, the harder and stronger it becomes, though ductility decreases. Age Hardening (Precipitation Hardening): Some high-tin phosphor bronze grades can be age-hardened through controlled heating after cold working. Typically done at around 250°C – 350°C for several hours. This helps in achieving a balance between hardness and toughness. Combination Treatment: Often, cold working followed by low-temperature annealing is used to fine-tune mechanical properties for specific applications like springs or bearings.

Weldability: Phosphor Bronze has good weldability when correct procedures are followed. The presence of phosphorus improves fluidity during welding but can make the alloy slightly more brittle if overheated. Recommended Welding Methods: TIG (GTAW) Welding: Provides clean, high-quality welds with precise control—ideal for thin sections.

Machining Characteristics: Machinability rating: approximately 40–50% compared to free-cutting brass (C36000 = 100%). The material is tough and slightly gummy, which can cause tool wear if incorrect speeds or feeds are used. Produces continuous chips, so the use of chip breakers and coolant is essential. Tooling Recommendations: Use sharp, high-speed steel (HSS) or carbide-tipped tools. Apply cutting fluids or lubricants to reduce friction and heat buildup. Maintain low to medium cutting speeds with steady feed rates to prevent tool chatter. Surface Finish: When machined properly, phosphor bronze provides an excellent surface finish and tight tolerances. Ideal for precision parts like bearings, bushings, gears, and valve components.

We are a leading dealer, supplier, stockist, and trader of high-quality Phosphor Bronze materials, offering a wide range of grades and sizes to meet diverse industrial applications. Our products are sourced from trusted and certified manufacturers, ensuring consistent quality, excellent mechanical properties, and reliable performance.