Arc Welding Service

Filler Metals

STELLITE 21 STELLITE 21

Nominal Composition (mass %) and Physical Properties

Others

Hardness**

Density

Melting Range

Base

26-29

4.5-6.0

0.20-0.35

Ni,Fe,Si,

Mn,Mo

27-40 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).

Stellite^® 21 (previously known as Stellite^® 8) 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 Stellte^® 21 composition. It was also one of the first heat-resistant

alloys trialled for ues in jet engines.

Stellite^® 21 consists of a CoCrMo alloy matrix containing dispersed hard carbides which stengthen 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 Stellite^®

21 are very dependent upon the manufacturing route and any subsequent heatments.

Dueto the low volume fraction of carbides, the Co-based alloy martrix dominates the wear and corrosion properties.

Stellite^® 21 has excellent cavitation, qalling and metal-tometal sliding wear resistance, but is not recommended for severe

hard particle abrasion. The surface can work harden considerbly during wear or even during, and the use of correct

machining tools and techniques is important to achieve optimal results.

Stellite® 21 has excellent resistance to thermal and mechanical shock. Optimum high temperature strength is obtained

by solution heat treatment at 1200-1240 ํC (2190-2265 ํ F) followed by quenching, and aging in the temperature

range 700-1150 ํ F).

Stellite^® 21 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

genneration. Due to its good impact resistance, it has been widly used in the building up of forging or hot stamping dies.

The oxyacetylene weld deposition method is not recommended for this alloy.

Corrosion Resistance

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

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

and sour gas) than CoCrW alloys such as Stellite^® 6. The 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 information regarding corrosion resistance can be provided on request.

Nominal Thermal Expansion Coefficient (from 20 ํC/68 ํ F to stated temperature)

100 ํ C

(212 ํ F)

200 ํ C

(392 ํ F)

300 ํC

(572 ํF)

400 ํ C

(752 ํ F)

500 ํ C

(932 ํ F)

600 ํ C

(1112 ํ F)

700 ํ C

(1292 ํ F)

800 ํ C

(1472 ํ F)

900 ํ C

(1652 ํF)

um/m.k

11.0

11.2

12.0

12.65

13.1

13.6

14.3

14.7

15.21

u-inch/inch- ํF

6.1

6.2

6.7

7.3

7.6

7.9

8.2

8.45

Nominal Tensile Properties at Room Temperature

Note.Th Mechanical properties of Stellite ^®21 are very dependent opon the manufacturing route and heat treatment.

	Utimate Tensile Strength Rm		Yield Stress Rp(0.2%)		Elongation	Elastic Modulus
	ksi	MPa	ksi	MPa	A(%)	psi	GPa
Invesment Castings or undiluted weld metal	103	710	82	565	9	36.2x10 ⁶	250
Stellite^® HS-21(*)	145	1000	87	650	20	35.5x10 ⁶	245

(*) "HS" = HIP -consolidated from the powder form

Nominal Hot Hardness (DPH) as-cast

20 ํC

(68 ํ F)

100 ํ C

(212 ํ F)

200 ํ C

(392 ํ F)

300 ํC

(572 ํF)

400 ํ C

(752 ํ F)

500 ํ C

(932 ํ F)

600 ํ C

(1112 ํ F)

700 ํ C

(1292 ํ F)

800 ํ C

(1472 ํ F)

900 ํ C

(1652 ํF)

347

279

248

228

208

197

181

153

123

Thermal and Electrical Properties

	Approximate value at Room Temperature
Thermal conductivity	14.5 W/m.k	100.5 Btu-in/hr/ft2/ ํF
Electrical resistivity	87.38u-ohm.cm	34.4 u-ohm.inch

Product Forms and Cross Reference Specifications

Stellite^® 21 is avalable as welding wire, rod , power, and electrodes; and finished castings and power-metallurgically produced P/M parts.

Deloro Stellite also offers hardfacing services.

Stellite^® 21 can be supplied to the follwing specifications:

SPECIFICATION	PRODUCT FORM
UNS R30021	Rod, Castings
UNS W73041	Wire
UNS W73021	Electrode
ams 5385	Castings
AMS 5819	Rod, Wire

SPECIFICATION	PRODUCT FORM
AWS A5.21 / ASME BPVC IIC SFA 5.21 ERCoCr-C	Rod
AWS A5.21 / ASME BPVC IIC SFA 5.21 ERCCoCr-c	Wire
AWS A5.13 / ASME BPVC IIC SFA 5.13 ECoCr-C	Electrode
SAE J467	HIP- Consolidated

Stellite is a registered Trade Name of Deloro Stellite.

Deloro Stellite manufactures sophisticated alloys in the form of casting, powders, coatings, consumables, and machined parts

that resist wear, corrosion, and abrasion. Information provided in this document is intended only for general guidance about

Deloro Stellite products and is the best information in our possession at the time. Product users may request information about

their individual use of our of our products, but Deloro Stellite does not warrant or guarantee this information in any way. Selection

and purchase of Deloro Stellite products is the sole responsibility of the product user based on the suitability of each use. Individual

applications must be fully evaluated by the user, including compliance with applicable laws, requlations, and non-infringement.

Deloro Stellite cannot knowor anticipate the many varibles thet affect individual product use and individual performance results

may vary. For these reasons, Deloro Stellite does not warrant or quarantee advice or information in this document, assumes no liability

regarding the same, and expressly disclaims any warranty of any kind,including any warranty of fitness for a particular pupose,

regarding the same.