Alloy 6B / UNS R30016 / AMS 5894

Description

Alloy 6B is a cobalt-based alloy with great wear, erosion and abrasion resistance. The wear resistance of alloy 6B is due to the chemical composition and is not a product of heat treatment or other hardening mechanisms. The low coefficient of friction of alloy 6B allows it to resist seizing and galling; proving useful in areas and applications where lubrication is difficult or impractical. Even under constant erosive conditions, alloy 6B has shown exceptional cavitation erosion resistance. Elevated temperature exposure has little effect on this alloy’s hardness, impact strength, and dimensional stability. Alloy 6B also maintains high hardness at elevated temperatures (approaching 2000°F) and will recover its original hardness upon cooling to room temperature. This unique property, coupled with good corrosion resistance to a multitude of media and superior mechanical properties in relation to its outstanding wear resistant characteristics, makes alloy 6B a versatile alloy that can be used in numerous applications where wear, corrosion and elevated temperature are concerns.

Why Alloy 6B is a Versatile Solution for Wear, Erosion and Corrosion
→ Read our Alloy Insights blog post

Industries & Applications

Alloy 6B is suitable for use in a variety of high wear and erosion applications. The abrasion resistance of this alloy allows it to be used as industrial scraper blades and knives in the food processing, waste water treatment and textile industries. Alloy 6B is used in applications where erosion is an issue such as nozzles, pumps, valves and mixing blades that are moving slurries where cavitation damage is a concern. This alloy has also found use in industrial sliding wear applications such as valves in chemical processing and turbine blade components for steam control in the power industry. Alloy 6B can also be found in bearing assemblies in heat treat furnaces.

Resistance to Corrosion

Alloy 6B also has corrosion resistance in a variety of media in addition to being wear resistant. Chromium, molybdenum, tungsten and nickel all provide additional resistance against corrosion. Alloy 6B is very resistant to oxidation at ambient temperatures and has good resistance to oxidation at elevated temperatures. Alloy 6B is resistant to different aqueous corrosive media at various concentration and temperature combinations. See the table on the next page for specifics.

Fabrication and Heat Treatment

The carbon content in alloy 6B may make it more difficult to machine compared to other cobalt based alloys, but tungsten carbide tools can still be used to machine this alloy. High speed inserts are not recommended but EDM techniques can be used to make threads in this alloy. Alloy 6B can be welded using a range of methods, including TIG, MIG, shielded metal arc and coated electrode welding. A preheat treatment to 1000°F should be used and maintained to prevent cracking during welding. Ventilation is needed to minimize exposure to airborne dust, fumes, and particulate matter when machining, grinding or welding this alloy. The standard heat treatment for alloy 6B is 2250°F (1232°C) followed by an air cool.

Common Trade Names

Stellite® 6B

Stellite® is a registered trademark of Deloro Stellite Company.

Download Our Alloy 6B Datasheet

Alloy 6B Available Forms:

Bar Icon
Sheet Icon
Plate Icon
Welding Products Icon

Chemical Composition (%)

(Co) Cobalt Remainder
(Cr) Chromium 28.0 – 32.0
(W) Tungsten 3.5 – 5.50
(Fe) Iron 3.0 max
(Ni) Nickel 3.0 max
(Mo) Molybdenum 1.5 max
(Mn) Manganese 0.5 – 2.0
(Si) Silicon 0.2 – 2.0
(C) Carbon 0.9 – 1.40
(P) Phosphorus 0.04 max
(S) Sulfur 0.03 max

Applicable Specifications

Form AMS Other
Bar AMS 5894 Deloro W3
Plate & Sheet AMS 5894 Deloro W1

 

Alloy 6B Frequently Asked Questions

1. What is Alloy 6B and what makes it unique among wear‑resistant alloys?

Alloy 6B is a cobalt‑based alloy engineered to provide exceptional resistance to wear, erosion, and corrosion, even at elevated temperatures. Unlike many alloys that rely on heat treatment for hardness, Alloy 6B derives its wear resistance from its chemical composition, allowing it to maintain performance in severe service conditions. Read our Alloy Insights blog post on Alloy 6B to learn more.

2. Why is Alloy 6B highly resistant to wear, galling, and erosion?

Alloy 6B’s naturally high hardness and low coefficient of friction enable it to resist sliding wear, galling, and seizing, even in poorly lubricated or non‑lubricated environments. It also exhibits excellent resistance to cavitation erosion, making it especially effective in pumps, valves, and other components exposed to constant abrasive or erosive forces.

3. How does Alloy 6B perform at elevated temperatures?

Alloy 6B maintains excellent hot hardness, meaning it retains its strength and wear resistance at elevated temperatures. After cooling to room temperature, the alloy fully recovers its original hardness, ensuring dimensional stability and consistent mechanical properties after prolonged heat exposure.

4. What types of corrosive environments can Alloy 6B withstand?

Alloy 6B offers strong corrosion resistance in both fresh and salt water, as well as in aqueous acids such as sulfuric and hydrochloric acid across a range of temperatures. It also performs well in high‑temperature environments involving steam, air, and hot gases, and in abrasive, corrosive slurries commonly found in cement, coal, pulp and paper, and bentonite processing.

5. What industries and applications commonly use Alloy 6B?

Alloy 6B is widely used in applications exposed to severe wear and erosion, including glass manufacturing dies, conveyor rollers, furnace nozzles, shear blades, pumps, valves, mixing blades, turbine components, industrial scraper blades, knives, and bearing assemblies in heat‑treat furnaces. Its durability makes it ideal for chemical processing, power generation, glass, food processing, wastewater treatment, and textile industries.

6. Is Alloy 6B difficult to machine or fabricate?

Because of its high carbon content and inherent hardness, Alloy 6B can be challenging to machine, with tungsten carbide tools typically recommended. Electrical discharge machining (EDM) is commonly used for threading. The alloy is weldable using TIG, MIG, and shielded metal arc welding, with preheating to approximately 1000°F recommended to reduce the risk of cracking. Standard heat treatment involves heating to 2250°F followed by air cooling.

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The information shown on this page is intended to be used as a guide and may be revised at any time without prior notice. The information is believed to be reliable and accurate, however Corrosion Materials does not make any warranty or assume any legal liability with respect to the accuracy, completeness or usefulness of the information.