Powder Metal MaterialsSAE 841 bronze, SAE 863 iron-copper and MPIF Standard 35 alloys
Symmco can provide material and mechanical properties according to MPIF standards. Their engineering team works closely with their suppliers and the Symmco processing team to maintain the proper material base to ensure that your customer-specifications are met.
A wide range of material options:
- Brass
- Soft Magnetics
- Sinter Hardened
- Pure Copper
- Bronze
- Iron
- Iron/Copper
- Ferrous Alloys
- Stainless Steel
- Nonferrous Alloys
(Nickel, Chromium, Molybdenum, etc.) - Soft Magnetic Composites (SMC)
Need to go beyond our material options?
Sometimes your needs may go beyond the scope of our extensive inventory of stock products.
With a diverse spectrum of both materials and manufacturing capabilities, Symmco has the versatility to deliver the custom solutions your industry demands.
- Tools to produce over 2,000 custom-made bushings
- Bushings in over 400 metric sizes
- Rapid in-house tool design
- Simple and complex component parts
- Gears
- Assemblies
- Ability to execute both long and short runs
Symmco has a variety of informational materials on custom parts in addition to the markets we serve.
Click on the links below to learn more:
SAE 841 bronze and SAE 863 iron-copper, side by side
Most of Symmco's stock catalogue is SAE 841 oil-impregnated sintered bronze, with SAE 863 sintered iron-copper covering the higher-load applications, and the table below sets the two materials beside each other using the figures Symmco has published. Where a cell reads “not published”, Symmco has not released that property for the material, so ask for it when you request a quote rather than assuming it matches the bronze column.
| Property | SAE 841 bronze | SAE 863 iron-copper |
|---|---|---|
| Designation | SAE 841 oil-impregnated sintered bronze | SAE 863 sintered iron-copper |
| MPIF designation | MPIF CT-1000-K26 | Not published |
| Composition | nominal 90% copper / 10% tin | Not published |
| Sintered density | 6.4 to 6.8 g/cc | Not published |
| Oil content by volume | 24% oil content by volume (industry standard 19%) | Not published |
| Minimum K-value | 30,000 minimum K-value (industry standard 26,500) | Not published |
| PV value | 50,000 | 35,000 |
| Maximum static load | 8,000 psi maximum static load | 20,000 psi maximum static load |
| Maximum surface speed | 500 surface feet per minute maximum surface speed | 500 surface feet per minute maximum surface speed |
| Standard oil and operating range | A high-grade, 100-viscosity, non-detergent rust and oxidation inhibited turbine oil, with an effective operating range of -10°F to 200°F | Not published |
| Lead-free | Yes | Not published |
| Food-grade option | Not offered | Not published |
| Typical use | Bushings and bearings that are self-lubricating and maintenance-free in most applications | Higher-load applications |
What each row means when you are sizing a bearing
- Designation and MPIF designation
- SAE 841 and SAE 863 are the bearing-material designations Symmco publishes for its two stock materials, while CT-1000-K26 is the MPIF Standard 35 designation Symmco uses for its bronze, so a buyer who specifies against MPIF can call out that designation directly and Symmco follows all MPIF standards in meeting it.
- Composition and sintered density
- Nominal 90% copper and 10% tin is the tin bronze the 841 designation describes. The sintered density of 6.4 to 6.8 g/cc sets the balance between metal and the interconnected pore space that holds the oil, and it is the figure a density note on a drawing should be checked against.
- Oil content by volume
- Oil content is the share of the finished bearing's volume that is oil, and Symmco's bronze holds 24% against the 19% that Symmco cites as the industry standard, which means more lubricant held in reserve before a bearing runs dry.
- Minimum K-value
- The K-value is the strength constant taken from a radial crush test of the bearing wall. Symmco's minimum of 30,000 sits above the 26,500 industry figure, so the wall tolerates more crushing load before it gives.
- PV value, maximum static load and maximum surface speed
- The PV value is bearing pressure multiplied by shaft surface speed, and it is the ceiling to check first when sizing a plain bearing. Maximum static load is the pressure the bearing carries with the shaft at rest, maximum surface speed is how fast the shaft may run at the bore, and the gap between iron-copper's 20,000 psi static rating and bronze's 8,000 psi is why iron-copper goes into the higher-load jobs.
- Standard oil and operating range
- Unless a drawing says otherwise, Symmco impregnates its bronze with a high-grade, 100-viscosity, non-detergent rust and oxidation inhibited turbine oil that has an effective operating range of -10°F to 200°F; other oils, including military-grade oils, are covered further down this page.
- Lead-free and food-grade
- Symmco bronze is lead-free. Symmco does not offer a food-grade bronze, so an application that needs a food-contact rating should be raised before the quote rather than after the parts arrive.
- Typical use
- SAE 841 bronze is the self-lubricating bearing material, maintenance-free in most applications, and SAE 863 iron-copper is what Symmco supplies for higher-load applications. Both are stocked as cored and solid bar stock for machining, and the bronze also as finished sleeve, flange and flanged bearings, thrust washers, plates and discs.
Which MPIF Standard 35 materials does Symmco run?
Symmco runs the majority of MPIF Standard 35 materials and follows all MPIF standards, as a member of the Metal Powder Industries Federation, so a drawing that calls out a Standard 35 designation can usually be quoted as drawn. Separately, the material families Symmco runs span bronze, iron-copper, iron, steel and stainless steel, along with the soft magnetic composites, whose Somaloy 1P, 3P and 5P grades are described on the Soft Magnetic Composites page.
The exception is any part that requires high-temperature sintering. Symmco does not manufacture those, and rather than discovering it late, Symmco identifies the requirement at quoting and discusses alternatives or other options with the customer before the part goes any further.
This page does not list Standard 35 designations code by code, so the quickest route with a specific alloy in mind is to send the drawing with the quote request, where the engineering team can confirm it against the material base it maintains with its suppliers and the sintering process the part will run through.
What oil goes into a Symmco self-lubricating bearing?
Oil impregnation is done in-house, and the standard fill is a high-grade, 100-viscosity, non-detergent rust and oxidation inhibited turbine oil, with an effective operating range of -10°F to 200°F. That is the oil a Symmco bronze bearing carries unless the drawing calls for something else, and it is the oil behind the 24% oil content by volume in the table above.
Multiple oil types are available, including special military-grade oils, so a part that needs a different viscosity, a military-grade oil or a lubricant matched to an unusual temperature can be specified that way on the drawing and impregnated to suit. Those military-grade oils are noted on the Markets page alongside the sectors Symmco serves.
The result, in either case, is a bearing that is self-lubricating and maintenance-free in most applications, because the oil held in the pores of the bronze feeds the bearing surface as the shaft runs.
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