Phosphor Bronze

Your guide to Phosphor Bronze Machining



A versatile material that offers very good corrosion resistance

Commonly used within the marine industry amongst others

Excellent spring qualities

Phosphor bronze is suitable for a wide range of applications and especially heavy duty components. However, it is very dense and difficult to machine, therefore an experienced specialist machinist should be employed.

This guide will take you through the main attributes, common applications, notes for designers and suitable finishing and treatments, as well as UK stock sizes and property tables. Don't forget to bookmark the page so you can refer back later.

If you are interested in phosphor bronze machined parts, please scroll to the bottom of the page for more information about our service and to request a quote.

Phosphor Bronze: Properties, Applications and Design Considerations


What is Phosphor Bronze?
Phosphor Bronze (also known as tin bronze or phos bronze) is an alloy of copper, tin and phosphorous. One of the oldest metal alloys, it is a versatile material that offers very good corrosion resistance. It is particularly used within the marine industry but also electrical, aerospace and chemical.

A number of grades of phosphor bronze are available. PB102 is the most common grade of wrought phosphor bronze used in the UK.

It has high corrosion resistance and excellent spring qualities – making it suitable for a wide range of applications and especially heavy duty components.


Phosphor Bronze Machinability


Phosphor Bronze is very dense and therefore machining it can present some challenges. It has a machinability rating of 20 (compared to Brass CZ121 at 100).

Very sharp cutting tools are required. Tipped tools are preferred. Plenty of coolant is recommended.

Here at Penta Precision, we have years of experience when it comes to machining Phosphor Bronze, so your parts will be in safe hands.


Similar or obsolete designation and trade names


You may also see Phosphor Bronze referred to as:

  • PB101 / CW450K / Cusn4
  • PB102 / CW451K / CuSn5 / UNS C51000 / ASTM B139 / QQ-B750 / SAE J461
  • PB103 / CW452K / CuSn6
  • PB104:
    • CW453K / CuSn8
    • CW459K / CuSn8P
    • CW455K / CuSn4Pb2P
    • CW457K / CuSn4Te1P
    • CW458K / CuSn5Pb1
    • CW460K / CuSn8PbP
    • CW454K / CuSn3Zn9
    • CW456K / CuSn4Pb4Zn4
  • AMS 4625 / NES838
  • DTD265A
  • BS1400 / PB1
  • LG2/CC491K
  • PB2
  • SAE660
  • PB1C
  • AMS 4510
  • BS2875
  • DEFSTAN 02-838 (Naval specification)
  • C544

Industry Examples: Electrical | Marine | Aerospace | Chemical | Architecture

Typical Components & Applications: Propellers | Bushes & bearings | Gears | Worm Gears | Springs | Fasteners | Pump & valve spindles | Shafts | Flanges | Connectors & switches

Main Attributes:
  • High corrosion resistance
  • High fatigue strength
  • Low coefficient of friction
  • Fine grain
  • Good spring properties
  • High mechanical properties
  • Difficult to machine
  • Good resistance to cold
  • Good thermal and electrical conductivity
Can we meet your phosphor bronze machining needs? Contact us now
Get a Quote


Phosphor Bronze Machined Parts


Penta Precision provides the following phosphor bronze machining services: 
  • CNC milling
  • CNC turning
  • Prototypes and batch runs
  • Insert installation
  • Part marking
  • Manual milling
  • Manual turning
  • Machining design advice
  • Design for manufacture service

Want to know more?


Find out how we can help you


Bronze Machining


Bronze Machining


Industry Sectors


Industry Sectors


Commitment To Quality


Commitment to Quality

Get A Quote