Porous sponge iron powder with top green strength and oil retention. Self-lubricating bearings, friction, welding electrodes, chemical grades. Lot-certified.
QUICK ANSWER
Sponge iron powder is produced by reducing iron ore or mill scale with solid or gas reductants, then milling the porous sponge into powder. Its porous, high-surface-area particles give the highest green strength of any iron powder and excellent oil retention, making it the classic grade for self-lubricating bearings, low-density structural parts, friction materials, welding electrodes, and chemical reactivity applications.
The sponge structure is the product: each particle is a tiny porous granule that mechanically interlocks on pressing (exceptional green strength at low compacting pressure), sinters actively (high surface area drives neck growth), and retains oil in its pore network (the original self-lubricating bearing material). It trades compressibility for these properties — you cannot press it as dense as water atomized iron — but in its application niches, nothing performs better per dollar.
MATERIAL DATA
Lot-level controls focus on the chemistry, particle characteristics, and process values that influence manufacturing consistency and finished-part performance.
| Element | Content | Performance Role |
|---|---|---|
| Iron (Fe) | > 97.5 wt% | Base metal in porous sponge form |
| Oxygen (O) | 0.3-0.8 wt% | Higher than atomized grades — internal oxides in the sponge structure |
| Carbon (C) | 0.02-0.10 wt% | Residual from the reduction process |
| Acid insolubles | < 0.4 wt% | Ore-derived residue — grade dependent |
| Metallic iron | > 94 wt% | Active fraction for chemical and welding uses |
Final limits can be aligned with the agreed purchase specification.
APPLICATIONS
Self-lubricating bearings are the signature application: sponge iron, often blended with copper, presses and sinters into porous bearing blanks that are vacuum-impregnated with oil — the sleeve bearings in every fan, appliance motor, and power tool. The sponge powder's pore network becomes the oil reservoir, and its green strength allows the low pressing densities (5.8-6.4 g/cm³) that maximize connected porosity. Bearing makers buy on green strength and pore-structure consistency.
The diversified second market spans friction materials (brake and clutch formulations use sponge iron as a structural filler), welding electrode coatings (where its chemistry and reactivity stabilize the arc), oxygen absorbers and warmers (Category 11 chemistry), and chemical iron applications. Enamelling-grade ground sponge iron and iron-fortification grades serve further niches — all valuing the same porous reactivity that defines the product.
PRESS & SINTER (PM) POWDERS
CUSTOM SUPPLY
We supply reduced sponge iron powder in standard PM cuts with certified green strength and apparent density, plus high-purity chemical grades with certified metallic iron content. Custom size distributions, copper-blended bearing premixes, and friction-grade activated powders are available. Not export-controlled.
We supply reduced sponge iron powder in standard PM cuts with certified green strength and apparent density, plus high-purity chemical grades with certified metallic iron content.
Custom size distributions, copper-blended bearing premixes, and friction-grade activated powders are available.
MATERIAL COMPARISON
| Comparison Point | This Product | Water Atomized Iron |
|---|---|---|
| Green strength | Highest — porous interlock | Good — dense irregular |
| Compressibility | Lower — 6.4-6.9 g/cm³ practical | Higher — 6.8-7.2 g/cm³ |
| Oil retention (bearings) | Excellent | Moderate |
| Chemical reactivity | High surface area | Lower |
| Cost | Lowest iron powder | Low |
| Best use | Bearings, friction, chemistry | Structural parts, gears |
TECHNICAL FAQ
Need a different chemistry, particle range, or processing route? Our material team can review the requirement and supply window.
Its internal porosity becomes part of the bearing's oil reservoir, and its green strength allows low-density pressing that maximizes connected porosity. The result is higher oil content and longer service life than atomized-powder bearings at the same press settings.
For low-to-moderate density parts (6.4-6.9 g/cm³) where strength requirements are modest, yes — it is the economical choice. Above that density range, water atomized or pre-alloyed grades are the better route.
High-purity reduced iron with certified metallic content and controlled carbon/sulfur for coating formulations — the standard iron powder of the electrode industry.
We certify green strength per lot at a reference compaction pressure and hold distribution within agreed windows — the parameter bearing makers depend on for unattended pressing.
No. Reduced iron powders are unrestricted commodities.
RELATED PRODUCTS
Compare neighboring grades from the same material family, then review the complete category for additional chemistry and particle options.
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Pre-alloyed CuSn10 with certified dimensional change per lot. Precision bushings, porous filters, marine PM. Lead-free compliant, custom cuts.
Cu, CuSn, CuZn friction powders with certified sintering behavior. Motorcycle, racing, wind and industrial brakes. Pre-blended matrices, IATF documentation.
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