C903 Tin Bronze: Replacing C922 & C932 Leaded Tin Bronze
TL;DR – Article Summary & Takeaways
- C903 tin bronze, also known as Navy “G” bronze or even CDA 903, is a high-strength non-ferrous (lead-free) alloy widely recognized for its exceptional corrosion resistance, pressure tightness, and ability to withstand wear.
- Erie Bronze & Aluminum frequently recommends C903 tin bronze as a suitable replacement for leaded C922 and C932 tin bronze for many applications, although not all.
- C903 is used to manufacture castings for pump impellers, gears, bushings, and bearings exposed to seawater and brine, as well as conditions that reach up to 550° F.
- C903 can be cast to meet requirements specified in the ASTM B763, ASTM B584, SAE J461, and SAE J462 standards.
C903 Tin Bronze as an Alternative to C922 and C933
While C903 Tin Bronze may not be the right solution for every job calling for C922 and C932 leaded tin bronze, it offers many of the same qualities in a non-leaded alternative. In this article, you can get to know each of these alloys better and determine if it is worth pursuing C903 Tin Bronze as an unleaded casting alternative to C922 or C932 bronze. Throughout this article, we will provide valuable information that can help you learn why we view C903 Tin Bronze as an alternative to C922 and C932 in many scenarios.
Benefits of C903 Tin Bronze / Navy “G” Bronze
While all bronze alloys produced by Erie Bronze are strong, some stand out for superior strength. C903 Tin Bronze is an excellent example of this. By adding tin to a bronze alloy, hardness, strength, and ductility can be improved. Our C903 tin bronze castings can withstand substantial wear and corrosion resistance while also offering a high load-carrying capacity.
Our customers have relied on C903 Tin Bronze castings for seawater and brine-exposed pump impellers, as well as a wide variety of gears, bushings, and bearings. Our Tin Bronze casting work has also been used to protect fittings that are regularly exposed to temperatures in the range of 550° F. C903 is often preferred for higher load-carrying capacities, wear resistance, and when environmental regulations restrict lead usage.
Comparing C903 Tin Bronze to C922 and C933
The primary difference between C903 Tin Bronze and the C922 and C932 Tin Bronze alloys is that they do not include lead. While these alloys are all bronze-based and include tin for increased strength, C903 is a lead-free alloy. Depending on your intended use for a C903 Tin Bronze casting, the lack of lead may prove irrelevant, and if it does, Erie Bronze is here to provide you with the casting you need. The comparison chart below shows the differences, performance traits, and typical applications for each alloy.
Tin Bronze & Leaded Tin Bronze Comparison Chart
| Alloy | Key Composition Difference | Lead Content | Primary Performance Traits | Typical Applications |
| C903 | Tin bronze alloy without lead | Lead-free | Higher strength, good corrosion resistance, good wear resistance, slightly lower machinability than leaded alloys | Structural bronze components, bushings, marine hardware, pump parts, valves, potable water applications where lead content is restricted. |
| C922 | Tin bronze alloy with added lead for machinability and bearing performance | Moderate lead content | Excellent machinability, good wear resistance, strong pressure handling, suitable for moving components | Bearings, bushings, thrust washers, gears, and industrial machinery components |
| C932 | Tin bronze alloy with higher lead content optimized for bearing performance | Higher lead content | Outstanding anti-friction properties, high load capacity, excellent machinability, widely used as a bearing alloy | Sleeve bearings, bushings, heavy equipment components, pumps, and automotive applications |
C903 Tin Bronze Castings Meet ASTM & SAE Standards
If your project calls for leaded Tin Bronze, it may also be listed as ASTM B763 or ASTM B584. An additional spec that calls for C932 leaded tin bronze alloy is the SAE 660 specification. Depending on your project’s spec sheet, you may see any of these terms used for leaded tin bronze alloys.
We will view C903 Tin Bronze as an Alternative to C922 and C932, depending on your needs and the casting’s intended use. C903 is also known as modified Navy G Tin Bronze. Additional specs C903 can conform to include ASTM B763, ASTM B763, SAE J461, and SAE J462.
Do C922 & C932 Still Have Advantages for Specific Applications?
Yes. While lead-free alloys such as C903 tin bronze are often preferred in certain environments, C922 and C932 tin bronze alloys still offer advantages in specific applications. The presence of lead in these materials helps improve resistance to dezincification by limiting zinc loss that can weaken the alloy over time. Lead also enhances machinability and provides additional friction resistance, making these alloys well-suited for moving components such as bushings, bearings, and other wear parts. Although C903 tin bronze can deliver many of the same performance benefits and offers a lead-free alternative, C922 and C932 remain valuable options where enhanced machinability and friction performance are priorities.
Premier Casting Partner for C903 Tin Bronze Parts & Components
Now that you have a better understanding of why we view C903 Tin Bronze as an Alternative to C922 and C932 in many cases. If you think your current job could be served by a C903 casting, we want to hear from you. Our team can help you confirm that C903 will meet your project’s needs. If it does, we will be ready to quote your casting job and get to work providing the Tin Bronze casting you need for a fair price. We alloy C903 and our other metals on-site and have decades of collective experience producing quality castings for industries ranging from power generation, Defense, machinery manufacturing, and more.
