Guide
When is aluminum bronze C954 the right choice for bushings and wear parts?
Aluminum bronze C954 is a cast copper alloy, UNS C95400, with typically 10 to 11.5% aluminum and 3 to 5% iron, sold as sand and continuous castings and machined into bushings, wear plates and other heavily loaded sliding parts. Short answer: choose it for slow-moving, heavily loaded bushings and wear parts that run on a hardened steel shaft with reliable lubrication; choose a tin or leaded bronze instead when the bearing must tolerate misalignment, dirt or occasional loss of lubricant.
By Saola Manufacturing engineering team · Published · Updated
Bronze bushings are usually specified by habit: C93200 for general use, C954 when something broke. This guide explains what C954 actually trades away for its strength, what it needs from the shaft and the lubricant, which cast forms and specifications to call, and how to write the drawing and RFQ so the bar and the test data match the job. The leaded versus lead-free bearing bronze question is covered separately in the C93200 vs C89835 guide.
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What is C954 aluminum bronze, and how does it differ from bearing bronze?
C954 is a high-strength aluminum-iron bronze, much stronger and harder than the tin and leaded tin bronzes used for general bushings. It gives up some of their forgiving, self-lubricating behavior in exchange.
The bronze bearing maker Bunting Bearings describes C95400 as a non-leaded alloy for low-speed, very high-load bearing applications that requires hardened steel shafts and constant lubrication with grease, graphite or molybdenum disulfide. That sentence contains the whole design rule. The alloy carries load well, but it is hard, it has no lead to smear into a lubricating film when the oil runs thin, and it is less able to bed in or swallow dirt particles than a softer bronze.
C954 can also be heat treated. Bunting lists minimum properties for an as-cast and a heat-treated condition, and the heat-treated material is stronger and harder. Specify which condition you need; they are not interchangeable on a drawing.
| Property | As cast | Heat treated |
|---|---|---|
| Copper | 83.00% min | 83.00% min |
| Aluminum | 10.00-11.50% | 10.00-11.50% |
| Iron | 3.00-5.00% | 3.00-5.00% |
| Tensile strength, min | 85,000 psi | 95,000 psi |
| Yield strength, min | 32,000 psi | 45,000 psi |
| Elongation, min | 12% | 10% |
| Brinell hardness (3000 kg load) | 170 | 195 |
| Machinability rating (maker's figure) | 60 | 60 |
Which bushings and wear parts suit C954?
Slow, heavily loaded, well-lubricated parts, such as pivot bushings on heavy equipment, press and roll bushings, and slide and wear plates. Fast, lightly loaded or dirty applications are usually better in a softer bronze.
The pattern is load first, speed second. C954's strength lets a bushing carry a high unit load without extruding or cracking, and its hardness resists wear from a matching hardened shaft. At high surface speed, the same hardness becomes a liability if the oil film breaks, because the bushing has less ability to deform and save the shaft. In dirty or poorly lubricated joints, a leaded or tin bronze that embeds grit and tolerates boundary lubrication is usually the safer pick.
| Condition in service | C954 aluminum bronze | Tin or leaded tin bronze |
|---|---|---|
| High unit load, slow motion or oscillation | Strong choice | May deform or wear faster |
| Hardened steel shaft available | Required | Works with softer shafts too |
| Reliable grease or oil supply | Required | Preferred, but more tolerant of lapses |
| Dirt or grit in the joint | Poor tolerance | Better embeddability |
| Misalignment or edge loading | Poor tolerance | More conformable |
| Lead-free requirement | Lead-free alloy | Leaded grades are not; lead-free tin bronzes exist |
What shaft and lubrication does a C954 bushing need?
A hardened steel shaft with a good finish, and lubrication that does not fail, delivered by a groove or fitting the bushing design actually feeds. A soft shaft in a C954 bushing tends to wear the shaft instead of the bushing.
The intent of a bushing is that the bushing wears and is replaced, not the shaft. With a hard bronze like C954 that only works if the shaft is harder still. Put the shaft hardness and surface finish on the shaft drawing, and match them to the bushing material on the assembly drawing so the pairing is visible to both suppliers.
Lubrication needs the same care. Specify the grease groove geometry, the fitting location and the relubrication interval, or a solid lubricant such as graphite plugs if the joint cannot be greased. For oscillating pivots, grooves that spread grease over the full loaded arc matter more than they do in a rotating bushing.
Which cast form and specification should you call for C954?
Call the form that matches the part: continuous cast bar per ASTM B505 for most machined bushings and plates, and sand castings per ASTM B148 for shaped parts; larger tubes and rings are also made as centrifugal castings under their own specification. Always give the UNS number C95400 and the temper.
The scope of ASTM B505 covers continuously cast rod, bar, tube and shapes in copper alloys; the 2018 edition's page lists B505/B505M-23 as the active replacement. Its abstract notes that mechanical tests are required only when the purchaser specifies them in the purchase order. That detail is easy to miss: a buyer who needs tensile or hardness data on the actual lot has to ask for it.
ASTM B148, the aluminum-bronze sand casting specification, lists C95400 among its alloys and determines mechanical properties from separately cast test bars, with the active version now B148-24. A separately cast test bar tells you about the melt, not about the wall of your particular casting, so for critical sand cast parts consider asking for hardness readings on the part itself.
What is C954 like to machine?
It machines reasonably well for a high-strength bronze, and the maker lists a machinability rating of 60, but it is harder than leaded bronzes. Expect more tool wear and slower rates than C93200, and plan the finish passes on bores accordingly.
Bushing bores and outside diameters are usually finished by turning or boring, with the press-fit outside diameter and the running bore held to separate tolerances. Because the bushing closes in when it is pressed into its housing, the bore size after installation is what matters to the shaft. State whether the bore tolerance applies before or after pressing, and if after, whether the bushing is to be line-reamed or bored in place. The press fit tolerance guide covers how much interference to allow.
Deburr grease grooves and oil holes carefully in any bronze bushing, and in a hard alloy like C954 especially, so no burr is left to score the shaft.
Can Saola machine C954 aluminum bronze parts?
Aluminum bronze is not on the bar list of the lead CNC plant's turning page, so the alloy, form and bar source are confirmed at drawing review before a quote is firm. The machining itself is CNC turning and milling at that plant.
The CNC turning page lists silicon bronze among its bar materials, and the CNC milling page covers second-operation machining on sand-cast brass and bronze, but neither page names C95400. If your bushing or wear plate needs C954, put UNS C95400, the specification, the condition and any mechanical test requirement on the drawing; material certification is available on request as described on the quality page. Send drawings through the quote form.
Frequently asked
Is C954 the same as nickel aluminum bronze?
No. C954 is an aluminum-iron bronze. Nickel aluminum bronzes such as C95500 and C95800 add nickel and are separate alloys with their own limits, so call the UNS number you actually need.
Is C954 lead-free?
It is not a leaded alloy, which is one reason it appears in lead-free bushing discussions. If you need a regulated lead limit, put that requirement on the drawing and ask for a certificate showing the measured lead.
Can C954 bushings run without lubrication?
Not well. The alloy relies on a lubricant film; for dry running, consider bushings with solid lubricant plugs, or a different bearing material.
How do I tell as-cast from heat-treated C954 on a certificate?
The certificate should name the temper or condition and report hardness or tensile results if you asked for them. Heat-treated material shows higher minimum strength and hardness, so state the condition on the drawing and check it on the certificate.
Should the shaft for a C954 bushing be hardened?
Yes. The maker's data says the alloy requires a hardened steel shaft, so state the shaft hardness on the shaft drawing.
Sources
- C95400 Aluminum Bronze continuous cast bars, product data, Bunting Bearings, accessed November 2026
- ASTM B505/B505M-18, Standard Specification for Copper Alloy Continuous Castings (scope and abstract; active version B505/B505M-23), ASTM International, 2018
- ASTM B148-18, Standard Specification for Aluminum-Bronze Sand Castings (scope; active version B148-24), ASTM International, 2018