ERCoCr-E Stellite 21 Hard Facing Rod Blue Color Make Various Liquid Valves Valve Seats

Stellite 21 ERCoCr-E Hard Facing Rod Blue Color Make Various Liquid Valves Valve Seats

WL-Co21 (previously known as WL-Co8) was developed in the mid 1930s as a corrosion resistant CoCr alloy, and rapidly found application as a biocompatible hip implant and denture alloy. Many of the alloys currently used in medical applications are variants of the original WL-Co21 composition. It was also one of the first heat-resistant alloys trialled for use in jet engines.

WL-Co21 consists of a CoCrMo alloy matrix containing dispersed hard carbides which strengthen the alloy and increase its hardness, but also decrease the ductility. The type, shape, size, and distribution of the carbides is strongly influenced by the processing history of the alloy, and for this reason the mechanical properties of WL-Co21 are very dependent upon the manufacturing route and any subsequent heat treatments.

Due to the low volume fraction of carbides, the Co-based alloy matrix dominates the wear and corrosion properties. WL-Co21 has excellent cavitation, galling and metal-to-metal sliding wear resistance, but is not recommended for severe hard particle abrasion. The surface can work harden considerably during wear or even during machining, and the use of correct machining tools and techniques is important to achieve optimal results.

WL-Co21 has excellent resistance to thermal and mechanical shock. Optimum high temperature strength is obtained by solution heat treatments at 1200-1240ºC (2190 - 2265ºF) followed by quenching, and aging in the temperature range 7001150°C (1290-2100°F). WL-Co21 can be cast, powder metallurgically processed, or applied as a weld hardfacing. It is recommended for applications involving cavitation, erosion, corrosion and/or high temperatures, such as valve trim for petrochemical and power generation. Due to its good impact resistance, it has been widely used in the building up of forging or hot stamping dies. The oxyacetylene weld deposition method is not recommended for this alloy.

Common Names: Stellite 21, BISHILITE (MHA) No.21, Weartech WT-21, Stoodite 21, POLYSTEL 21

Standard: AWS 5.21-2001 ERCoCr-E

Chemical Composition(%)

Characterisitic

Packing Details

For length 350mm 500mm pack in carton each 5kg
For 1000mm packing in 5kg tube, 4 tubes in one 20kg carton
For length more than 1000mm, pack in wooden box directly

Applications

Used to make various liquid valves, valve seats
Water turbine blade, hot forging die

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