Stellite 21 Scrap Buyer, Importer and Exporter in India
Stellite 21 lots are usually smaller than Stellite 6 lots, and they are easily lost inside a general "Stellite" heap. Mipra Steel buys them as their own grade so the molybdenum is paid for and does not end up in a melt that wanted tungsten.
Sell Stellite 21 Scrap
Describe the material (castings, hardfacing consumables, worn valve trim, PM parts), the weight and location, and send photographs. A reading that shows molybdenum and no significant tungsten confirms the grade fastest. We review incoming enquiries and respond with relevant next steps.
Buy Stellite 21 Scrap
Melters of cobalt-chromium-molybdenum alloys can tell us the quantity, accepted forms, nickel and iron limits and destination. Lots are described as Stellite 21, UNS R30021, with readings attached.
What Is Stellite 21 Scrap?
Stellite 21 is the oldest of the molybdenum-bearing Stellites. It was developed in the mid-1930s as a corrosion-resistant alloy, was once sold as Stellite 8, and is close in chemistry to the ASTM F75 implant alloy. Instead of the tungsten found in Stellite 6, it relies on about 5.5% molybdenum dissolved in a cobalt-chromium matrix, with fewer carbides and a little nickel.
That chemistry makes it tougher and less hard than Stellite 6 (about 27 to 40 HRC against 36 to 46). It handles cavitation, galling and metal-to-metal sliding well, and resists reducing environments such as sulphuric and hydrochloric acid and sour gas better than the cobalt-chromium-tungsten grades. Valve trim in petrochemical and power plants is the main use. Its impact resistance also makes it a choice for building up forging and hot-stamping dies.
In scrap terms, Stellite 21 is a cobalt-molybdenum feed. Melters who make F75-type or other Co-Cr-Mo alloys value it; melters making tungsten-bearing cobalt alloys do not want the molybdenum. Selling it as "Stellite" without the number throws that difference away.
Stellite is a trademark of its owner; the name is used only to identify the alloy.
Stellite 21 is part of the cobalt alloy family. Its closest relative on this site is F75 Co-Cr-Mo.
Where Stellite 21 Scrap Comes From
Most Stellite 21 scrap comes from valve and die work.
Valve Trim Overhaul
Worn seats, discs, plugs and cages replaced in refinery, petrochemical and power-plant valves.
Hardfacing Consumables
Rod and electrode stubs, wire ends and surplus powder for PTA and laser cladding.
Castings and PM Parts
Rejected cast or HIPed trim parts and machining offcuts from them.
Die Repair Shops
Ground-off build-up and worn deposits from forging and hot-stamping dies; usually mixed with die steel.
Stellite 21 Scrap Specification Chart
| Grade | Stellite 21 |
|---|---|
| UNS | R30021 |
| Former name | Stellite 8 |
| Alloy type | Cobalt-chromium-molybdenum-nickel, carbide-bearing |
| Density | about 8.33 g/cm³ |
| Melting range | about 1295 to 1435°C |
| Hardness | 27 to 40 HRC (290 to 430 HV) |
| HS code (customs heading) | 8105.30 (cobalt waste and scrap) |
Stellite 21 Chemical Composition
Nominal composition in mass per cent from the Deloro Stellite 21 material data sheet. Carbon, boron, silicon and manganese are present as minor elements with limits set by the product specification.
| Element | Symbol | Nominal mass % |
|---|---|---|
| Cobalt | Co | Balance |
| Chromium | Cr | 27.0 |
| Molybdenum | Mo | 5.5 |
| Nickel | Ni | 2.5 |
| Iron | Fe | 1.5 |
| Carbon, boron, silicon, manganese | C, B, Si, Mn | Minor |
Stellite 21 Equivalent Grades and Other Names
| Designation | Value |
|---|---|
| Trade name | Stellite 21 |
| UNS | R30021 |
| Former trade name | Stellite 8 |
| Closest standard alloy | ASTM F75 cast Co-Cr-Mo (UNS R30075), similar but not identical |
Stellite 21 Applications
- Valve trim for petrochemical and power generation service
- Parts exposed to cavitation, galling and metal-to-metal sliding
- Building up forging and hot-stamping dies
- Hardfacing by TIG, MMA, MIG, PTA and laser cladding
It is not recommended for severe abrasion by hard particles; Stellite 6 or harder grades are used there.
How Stellite 21 Scrap Is Identified
One reading usually settles it: molybdenum present, tungsten absent.
| Check | What it shows |
|---|---|
| Molybdenum about 5.5% | The defining element. Stellite 6 has tungsten instead. |
| Nickel about 2.5% | Higher than in Stellite 6 and F75; a useful secondary check. |
| Tungsten near zero | Rules out Stellite 6, Stellite 12 and Haynes 25. |
| Iron | High iron on a deposit means steel dilution, not a different grade. |
Grades Most Often Confused with Stellite 21
- F75 Co-Cr-Mo: very similar Co-Cr-Mo chemistry, made to the ASTM F75 implant standard; the source of the scrap usually tells them apart.
- Stellite 6: tungsten-bearing, harder, with more carbon.
Preparing Stellite 21 Scrap for Sale
- Keep Stellite 21 away from Stellite 6 and other tungsten-bearing hardfacing.
- Separate castings and consumables from die-repair grindings, which carry die steel.
- Strip steel holders, springs and packing from valve trim.
- Mark every container with the grade and keep the readings with it.
Stellite 21 Scrap Price per Kg: What Decides It
Offers are dated and built from contained metal, not from a list price.
- Cobalt content, about 63% of the alloy.
- Molybdenum credit, valuable to a Co-Cr-Mo melter and a penalty for a tungsten-alloy melter.
- Iron and steel contamination from die build-up or overlays.
- Form and cleanliness.
- Grade evidence and lot size.
Stellite 21 Scrap Import and Export
Importing into India
Worn trim from Gulf refineries and Asian power plants reaches India by container. Describe it as Stellite 21 cobalt alloy scrap with molybdenum readings, so customs and the buyer see a single grade. Guidance: importing alloy scrap. We buy as a nickel alloy scrap importer and buyer in India.
Exporting from India
Single-grade Stellite 21 is shipped to Co-Cr-Mo melters abroad with a packing list by form. East Asian buyers can deal through our South Korea office. See export documents. Lots leaving India go through our nickel alloy scrap exporter desk.
Customs heading: 8105.30 (cobalt waste and scrap); the national line has further digits.
Related Reading
Stellite 21 FAQ
What is the difference between Stellite 6 and Stellite 21?
Stellite 6 is a cobalt-chromium-tungsten alloy with about 1.2% carbon and higher hardness. Stellite 21 replaces the tungsten with about 5.5% molybdenum, carries less carbon and some nickel, and is tougher and better in reducing corrosive media.
Is Stellite 21 the same as Stellite 8?
Yes. Stellite 21 (UNS R30021) was previously known as Stellite 8.
Is Stellite 21 the same as ASTM F75?
They are similar Co-Cr-Mo alloys but not the same product. F75 is made to the ASTM F75 surgical implant specification; Stellite 21 is a wear and corrosion alloy. Scrap from implant foundries is sold as F75.
How should Stellite 21 scrap be sorted?
By grade first, keeping it away from tungsten-bearing Stellites, then by form: castings and consumables apart from overlays and die grindings that carry steel.
Which HS code applies to Stellite 21 scrap?
Heading 8105.30, cobalt waste and scrap, because cobalt is the largest element. Your customs broker confirms the full tariff line.
Sources and Review
Figures are quoted as published in these sources; any value we could not confirm has been left out.
- Deloro Stellite 21 material data sheet (MDS, rev. 00): nominal composition, density, melting range, hardness, product forms and corrosion notes.
- ASM Alloy Digest Co-139, Deloro Stellite 21 (abstract): UNS R30021, former name Stellite 8, similarity to ASTM F75, development history.
Reviewed by Mitesh Shah, Proprietor, Mipra Steel · Published by Mipra Steel, Khetwadi, Mumbai · Last updated