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STELL ITE 21 ALLOY T E C H N I C A L D A TA

Nominal Composition (mass %) and Physical Properties

MMA WELD DEPOSITION MIG WELD DEPOSITION PTA & LASER WELD DEPOSITION

Stellite 21 (previously known as Stellite 8) was devel-oped in the mid 1930s as a corrosion resistant CoCr alloy,

and rapidly ound application as a biocompatible hipimplant and denture alloy. Many o the alloys currentlyused in medical applications are variants o the originalStellite 21 composition.It was also one o the rst heat-resistant alloys trialled or use in jet engines.

Stellite 21 consists o a CoCrMo alloy matrix contain-ing dispersed hard carbides which strengthen the alloyand increase its hardness, but also decrease the ductility.Te type, shape, size, and distribution o the carbides isstrongly inuenced by the processing history o the alloy,and or this reason the mechanical properties oStellite21

are very dependent upon the manuacturing route andany subsequent heat treatments.

Due to the low volume raction o carbides, the Co-basedalloy matrix dominates the wear and corrosion properties. Stellite 21 has excellent cavitation, galling and metal-to-metal sliding wear resistance, but is not recommended or severe hard particle abrasion. Te surace can work hardenconsiderably during wear or even during machining, and the use o correct machining tools and techniques is importantto achieve optimal results.

Stellite 21 has excellent resistance to thermal and mechanical shock. Optimum high temperature strength is ob-tained by solution heat treatments at 1200-1240C (2190 - 2265F) ollowed by quenching, and aging in the tempera-ture range 700-1150C (1290-2100F).

Stellite 21 can be cast, powder metallurgically processed, or applied as a weld hardacing. It is recommended or ap-

plications involving cavitation, erosion, corrosion and/or high temperatures, such as valve trim or petrochemical andpower generation. Due to its good impact resistance, it has been widely used in the building up o orging or hot stamp-ing dies. Te oxyacetylene weld deposition method is not recommended or this alloy.

Optical Micrograph of a Stellite 21 investment casting (as-cast,

etched, 200X). The carbides in Stellite 21are usually of the type

TIG WELD DEPOSITION

Co Cr Mo C Others Hardness** Density Melting Range

Base 26-29 4.5-6.0 0.20-0.35

Ni

2.0-3.0 Fe, Si, Mn27-40 HRC**

290-430 HV**

8.33 g/cm3

0.301 lb/in3

2360-2615 F

1295-1435 C

** Higher values indicate a typical work hardened surface. Stellite 21 can work harden up to 550HV (48HRC).

HVOF & PLASMA SPRAY DEPOSI-

Corrosion Resistance

Stellite 21 is resistant to oxidizing and reducing gaseous atmospheres up to 1150C (2100F). Because its ternary alloy-

ing element is Mo and not W, it has higher resistance to reducing or complex environments (e.g. sulphuric acid, hydro-

chloric acid, and sour gas) than CoCrW alloys such as Stellite 6. Te typical electrode potential in sea water at room

temperature is approx. -0.3 V (SCE). Like stainless steels, Stellite 21 corrodes primarily by a pitting mechanism and not

by general mass loss in seawater and chloride solutions. More inormation regarding corrosion resistance can be pro-

vided on request.

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Deloro Stellite manuactures sophisticated alloys in the orm ocastings, powders, coatings, consumables, and machined partsthat resist wear, corrosion, and abrasion. Inormation pro-

vided in this document is intended only or general guidanceabout Deloro Stellite products and is the best inormation inour possession at the time. Product users may request inor-mation about their individual use o our products, but DeloroStellite does not warrant or guarantee this inormation in anyway. Selection and purchase o Deloro Stellite products is thesole responsibility o the product user based on the suitabilityo each use. Individual applications must be ully evaluatedby the user, including compliance with applicable laws, regu-lations, and non-inringement. Deloro Stellite cannot knowor anticipate the many variables that afect individual productuse and individual perormance results may vary. For thesereasons, Deloro Stellite does not warrant or guarantee adviceor inormation in this document, assumes no liability regard-ing the same, and expressly disclaims any warranty o any kind,including any warranty o tness or a particular purpose, re-

garding the same.

UK SALES OFFICE

Deloro StelliteCheney Manor Industrial EstateSwindon SN2 2PWUK

Tel: (+44) 1793-498500Fax: (+44) 1793-498501

E-Mail: saleshad@stellite.com

Literature Number: DS-2149Copyright 2007 Deloro StellitePrinted in USA

www.stellite.com

US SALES OFFICE

Stellite Coatings1201 Eisenhower Drive NorthGoshen, Indiana 46526

USA

Tel: (+1) 574-534-2585Fax: (+1) 574-534-3417

E-Mail: saleshad@stellite.com

-inch/inch-F 6.1 32.2

Nominal Thermal Expansion Coefficient (from 20C to stated temperature)

100C

(212F)

m/m.K 11.0

6.2

200C

(392F)

11.2

6.7

300C

(572F)

12.0

7.0

400C

(752F)

12.65

7.3

500C

(932F)

13.1

7.6

600C

(1112F)

13.6

7.9

700C

(1292F)

14.3

8.2

800C

(1472F)

14.7

8.45

900C

(1652F)

15.21

Stellite HS-21 (*) 145 1000 650 35.5x10 6 245

(*) HS = HIP -consolidated from the

Note: The Mechanical properties of Stellite 21 are very dependent upon the manufacturing route and heat treatment.

powder form .

Nominal Tensile Properties at Room Temperatur e

Ultimate Tensile Strength Rm Yield Stress Rp(0.2%) Elongation Elastic Modulus

ksi MPa ksi MPa A(%) psi GPa

103 710 82 565 6

100C

(212F)279

200C

(392F)248

300C

(572F)228

400C

(752F)208

500C

(932F)197

600C

(1112F)181

700C

(1292F)153

800C

(1472F)123

900C

(1652F)92

20C

(68F)347

Stellite is a registered Trade Name of Deloro Stellite.

Rod, WireAMS 5819

Nominal Thermal and Electrical Properties

Approximate value at Room T

Thermal conductivity 14.5 W/m.K

Electrical resistivity 87.38 -ohm.cm 34.4 -ohm.inch

PRODUCT FORM SPECIFICATION PRODUCT FORM

Rod, Castings AWS A5.21 / ASME BPVC IIC SFA 5.21 ERCoCr- Rod

UNS W73041

Electrode

AWS A5.21 / ASME BPVC IIC SFA 5.21 ERCCoCr- ire

UNS W73021

CastingsAMS 5385

Wire

AWS A5.13 / ASME BPVC IIC SFA 5.13 ECoCr- lectrode

SPECIFICATION

Product Forms and Cross Reference Specifications

36.2x10 2509

2087

UNS

SAE HIP - Consolidated

Temperature

100.5 Btu-in/hr/ft/F

Investment Castings orundiluted weld metal

Nominal Hot Hardness (DHP) of undiluted weld deposit

DS01-22208 (S R080