Methods Of Marking


A stencil and white or black paint, whichever shows up better on the metal being marked, should be used when the size of the metal piece permits. The federal or military specification numbers should be stenciled on the metal in vertically or horizontally aligned rows. The distance between the vertical rows should not exceed 36 inches, and the distance between the horizontal rows should not exceed 10 inches.


Stamping the specification number into the metal should be used when it is impossible to use the stencil method. It is usually necessary to cut or eliminate the marked portion of the metal prior to using the material for work stock. Therefore, the marking should be located where waste will be held to a minimum. Gothic style numerals and letters should be used; the height may be 1/16 inch, 1/8 inch, or 1/4 inch, depending upon the size of the material being marked.


Symbol Designation
F As Fabricated
O Annealed, recrystallized (wrought products only)
H Strain Hardened
H1 Plus one or more digits, Strain hardened only
H2 Plus one or more digits, Strain hardened and partially annealed
H3 Plus one or more digits. Strain hardened and stabilized.
W Solutoin heat treated-unstable temper. This designation is specified when the natural aging is specified.
T Treated to produce stable tempers other than F. O. or H.
T2 Annealed (cast products only).
T3 heat-treated and then cold work.
T4 heat-treated and then cold work.
T5 heat-treated and then cold work.
T6 heat-treated and then cold work.
T7 Solution Heat-treated and then stabilized.
T8 Solution Heat-treated cold-worked and then artificially aged.
T9 Solution Heat-treated artificially aged and then cold-worked .
T10 Artificially aged and then cold-worked .
dmt logo

  800-476-4849  |  170 Aprill Drive  |  Ann Arbor, Michigan 48103  |  USA