Guide
Leaded C93200 or Lead-Free C89835 Bronze for Custom Bushings?
C89835 bronze is a copper-tin-zinc bearing bronze with bismuth in place of the lead found in C93200, sold by bar suppliers as a lead-free replacement for that leaded alloy. It can replace C93200 in many bushings, but it lubricates less well and still carries a small, nonzero lead limit, so a lead-free claim depends on the lot documents rather than the alloy name.
By Saola Manufacturing engineering team · Published · Updated
General information, not legal advice. This guide is for engineers and buyers who design plain bearing bushings and are asked to drop lead. It compares the two bars as their suppliers publish them, explains why a lead-free claim needs documents, and lists what to write on the drawing and in the RFQ. Figures come from the linked supplier and regulatory pages; supplier typicals are not specifications.
On this page
What actually changes when C89835 replaces C93200?
C89835 swaps the 6 to 8% lead in C93200 for 1.7 to 2.7% bismuth, and Bunting sells it as a no-lead replacement with similar properties (Bunting product catalog). The catch is lubrication: bismuth does not lubricate as well as lead, so a constant lubricant supply is recommended.
C93200, also called SAE 660 or 83-7-7-3 (copper, tin, lead, zinc), is the common cast bearing bronze for bushings. ThomasNet describes its lead as discrete particles that can smear across the sliding surface and help resist seizure (ThomasNet, All About Bearing Bronze, accessed 2026). C89835 is a copper-tin-zinc bronze with bismuth taking the place of that lead, and National Bronze lists it as a lead-free alternative for C93200 (National Bronze, C89835).
Table 1 puts the two compositions and the minimum properties side by side for continuous cast bar. Notice that the lead line for C89835 is not zero and that two distributors print different maximums.
| Property | C93200 (leaded) | C89835 (bismuth) |
|---|---|---|
| Copper (% by weight) | 81.00 to 85.00 | 85.00 to 89.00 |
| Tin (% by weight) | 6.25 to 7.50 | 6.00 to 7.50 |
| Lead (% by weight) | 6.00 to 8.00 | 0.05 max (Bunting); 0.09 max (National Bronze) |
| Zinc (% by weight) | 2.00 to 4.00 | 2.00 to 4.00 |
| Bismuth (% by weight) | not listed | 1.7 to 2.7 |
| Tensile strength, min (ksi) | 35 | 30 |
| Yield strength, min (ksi) | 20 | 14 |
| Elongation, min (%) | 10 | 12 |
| Machinability rating | 70 | 70 |
Does C89835 run and wear like C93200 in a bushing?
Not identically. Bunting says properties are similar but that bismuth lubricates less well, and the continuous cast minimums for tensile and yield strength are lower for C89835 in Table 1 (Bunting, 2020).
Even C93200 is not self-sufficient: ThomasNet says it is not truly self-lubricating, still benefits from proper lubrication, and is not intended for prolonged dry running, with lead helping only at startup and in marginal lubrication (ThomasNet). A bismuth alloy has less of that cushion, so treat it as a lubricated bearing: grease or oil supply, grooves where the design allows, and a hardened, smooth shaft.
Compare like with like when you read data sheets. National Bronze prints typical values for sand-cast C89835 that look much closer to C93200 than the continuous cast minimums do (National Bronze, C89835; National Bronze, C93200), but cast form and temper differ. Check the minimums for the cast form you will actually buy, and recheck wall thickness and press-fit retention if you move to the lower-yield alloy.
Why does “lead-free” depend on the paperwork rather than the alloy name?
Because C89835 limits lead but does not eliminate it, and the limit that counts is the one in your customer’s specification or regulation. Distributors list the lead maximum at 0.05% or 0.09% by weight, and the Bunting catalog page for C89835 still carries a California Proposition 65 warning naming lead and nickel (Bunting item page).
For electrical and electronic equipment, Directive 2011/65/EU (RoHS) sets a maximum of 0.1% lead by weight in each homogeneous material in Annex II, and the 2011 text of Annex III listed point 6(c), an exemption for copper alloy containing up to 4% lead by weight (EUR-Lex, Directive 2011/65/EU, 2011). Annex III exemptions carry expiry dates and have been reviewed and amended since 2011, so read the current consolidated text, and the dates for your product category, before relying on 6(c). Typical lead maximums of 0.05% or 0.09% sit below the 0.1% figure on paper, while C93200 at 6 to 8% lead is above the 4% figure named in that exemption (Bunting, 2020).
Many bushings are not in RoHS scope at all. ThomasNet notes that lead content may affect RoHS, REACH, drinking-water and food-contact compliance depending on application and jurisdiction (ThomasNet). So ask what threshold your customer actually cites, and write it on the drawing. Drinking-water parts follow a separate path; the lead-free brass and NSF 61 guide covers it.
Which bronze should you specify for which job?
Use C93200 where lead is allowed and lubrication may be marginal, and C89835 where lead is restricted and the bushing is reliably lubricated. If the job is neither, the right answer may be a different bronze or a different bearing type.
Table 2 turns that into a short selection list. It is industry guidance, not a design calculation; run your own load, speed and temperature check for the application, and ask the bar supplier for the pressure-velocity data on the exact alloy and cast form.
| Requirement | Usual choice | What to check |
|---|---|---|
| No lead restriction; marginal lubrication or occasional starvation | C93200 | Lead helps at startup, but the alloy is not meant for prolonged dry running |
| Lead restricted by the customer, a specification or RoHS scope; oil or grease lubricated | C89835 | Lubricant supply must be constant; document the lead maximum |
| Drinking water or food contact | Neither by alloy name alone | Product listing under the relevant drinking-water standard |
| Heavy load, higher temperature or abrasive contamination | Possibly a harder bronze | Aluminum bronze or manganese bronze are the usual alternatives |
| No lubricant at all | Neither | Consider a solid-lubricant or polymer bearing |
Will lead-free bronze machine and finish like the leaded alloy?
Bunting rates both alloys at a machinability of 70 in its catalog, and National Bronze explains that bismuth, like lead, forms low-melting pools in the copper matrix that aid chip breaking (Bunting; National Bronze). Expect similar turning behavior, with the shop adjusting tools and feeds to the bar it actually receives.
The harder machining question is traceability. If a customer will audit a lead-free claim, leaded and lead-free bar should be identified, stored and cut separately, and chips should not be mixed. That is a handling rule for the supplier to confirm, not something an alloy name guarantees.
What should the drawing and RFQ say to get lead-free bronze bushings?
Name the alloy by UNS number and cast form, state the lead limit as a percentage by weight at your threshold, and ask for the documents that prove it for each lot. Then ask how lead-free bar is kept separate from leaded bar.
- Material: UNS C89835, continuous cast bar (or the cast form you want), with the specification you buy to.
- Lead limit: a maximum percentage by weight that matches your customer’s or regulator’s threshold.
- Documents: chemical analysis for the heat or lot, a lead-free declaration from the bar supplier, and heat or lot traceability on the packing documents.
- Coatings: no leaded plating or coating on a part sold as lead-free.
- Lubrication: a note that the bushing is a lubricated bearing, plus any oil grooves or holes on the drawing.
- Inspection: bore, outside diameter and length, with the bore stated before or after pressing.
Saola turns bushings from bar at its lead CNC plant (CNC turning). Bearing-bronze grades such as C93200 and C89835 are not among the bar materials listed on that page, so name the alloy and cast form in the RFQ and ask the quote to confirm whether that bar can be run, what compliance documents would ship with each lot, and the production site and country of origin, which every Saola quote states. Send the drawing through the quote form.
Frequently asked
Is C89835 RoHS compliant?
RoHS compliance is a statement about a finished product and its lot, not about an alloy name. The published lead maximums of 0.05% to 0.09% sit under the 0.1% limit in Annex II of Directive 2011/65/EU (EUR-Lex), but you still need the analysis or declaration for the bar actually used.
Can C89835 be used for drinking-water parts?
Not on the alloy name alone. National Bronze lists pipe fittings and pump components among its applications (National Bronze), but drinking-water use is governed by product listings under the applicable standard; see the lead-free brass guide linked above.
What does SAE 660 mean?
SAE 660 is the SAE designation for UNS C93200, the high-leaded tin bronze, shown by Bunting as 83-7-7-3 and ASTM B505 (Bunting catalog, 2020).
Does a Proposition 65 label mean C89835 contains a lot of lead?
No. The warning on the Bunting page names lead and nickel as chemicals the product can expose you to (Bunting item page), which is consistent with a low, nonzero lead limit. Ask for the lot analysis if the exact figure matters.
Sources
- National Bronze, C89835 lead-free bronze, product page, accessed October 2026
- National Bronze, C93200 bearing bronze, product page, accessed October 2026
- Bunting Bearings, product catalog (C93200 and C89835 pages), catalog dated 2020
- Bunting Bearings, C89835 bronze bars item page, catalog page, accessed October 2026
- ThomasNet, All About Bearing Bronze, article, accessed October 2026
- EUR-Lex, Directive 2011/65/EU (RoHS), Annex II and Annex III point 6(c), European Union, 2011