Metals - Orthopaedic Biomaterials in Research and Practice - page 178

Table 7.3 stainless steel alloy mechanical properties

Alloy
ASTM F 55, F 138 F 2229 F 1586 F 1314 F 745

ISO 5832-1

Other AISI 316L,

UNS S31673

UNS S29108 UNS S31675 UNS S20910

Mechanical properties
Fe-17Cr-14Ni-
2.5Mo

23Mn-21Cr-
1Mo

21Cr-10Ni-
3Mn-2.5Mo

22Cr-12.5Ni-
5Mn-2.5Mo

Tensile modulus
(Y, GPa)

192-201 # # # #

0.2% Yield strength
(σ 0.2% , min, MPa)

170 a 586 a 430 a 380 a 205 c

250 hf
3l0 cw 1227 cw 862 cw

1200 cf a

Ultimate strength
(σ u , min, MPa)

480 a 931 a 740 a 690 a 480 c

550 hf
655 cw 1496 cw 1035 cw

1300 cf a

Strain to failure
(ε u , min, %)

40 a 52 a 35 a 35 a 30 c

55 hf
28 cw 19 cw 12 cw

12 cf a

Hardness 85 RB a

30 RC cw

Note: a, Annealed; c, as cast; cw, 30% cold worked; cf, cold forged; hf, hot forged; RB, Rockwell B; RC,
Rockwell C; #, not reported, close to F 55.

a

F 138.

properties and are resulting in a resurgence of interest in the use of stain-
less steel in joint replacement components. Although cast stainless steel
was used in early joint replacement prosthesis components, this has been
largely abandoned since early casting alloys displayed inadequate yield
and fatigue strengths, resulting in unacceptable incidences of medullary
stem bending and component fatigue fracture.

Cobalt-base alloys

Compositions F 75 is the traditional cast alloy and is probably the one in most

common use today. It was originally called Vitallium (Howmedica,
Inc., Rutherford, New Jersey), and unfortunately this name is fre-
quently used incorrectly to refer to the whole class of cobalt-base
alloys. There is a modified version, F 799, which is used both as a hot
forging alloy and as a base material for powder metallurgic processes
( Table 7.4).