ASTM B550 Specification

This specification2 covers three grades of zirconium and zirconium alloy bar and wire. Unless a single unit is used, for example corrosion mass gain in mg/dm2 , the values stated in either inch-pound or SI units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore each system must be used independently of the other. SI values cannot be mixed with inch-pound values.

Chemical CompositionA

Element Composition, %
Grades R60702 Grades R60704 Grades R60705
Zirconium + hafnium, min 99.2 97.5 95.5
Hafnium, max 4.5 4.5 4.5
Iron + chromium 0.2 max 0.2 to 0.4 0.2 max
Tin . . . 1.0 to 2.0 . . .
Hydrogen, max 0.005 0.005 0.005
Nitrogen, max 0.025 0.025 0.025
Carbon, max 0.05 0.05 0.05
Niobium . . . . . . 2.0 to 3.0
Oxygen, max 0.16 0.18 0.18
Note:

A. By agreement between the purchaser and the manufacturer, analysis may be required and limits established for elements and compounds not specified in the table of chemical composition.

Mechanical PropertiesA

  Grades
R60702 R60704 R60705
Tensile Strength, min, ksi (MPa) 55 (380) 60 (415) 80 (550)
Yield Strength, min, ksi (MPa) 30 (205) 35 (240) 55 (380)
Elongation in 2 in. or 50 mm min, %B 16 14 16
Note:

A. For bar only.
B. When a sub-size specimen is used, the gage length shall be as specified in Test Methods E 8 for the specimen.