|
|
What's in an Engine &
Why? |
|
F: As-fabricated. Shaped by cold
working, or casting processes in which no special control is placed over
thermal conditions or strain hardening. No mechanical property limits are set
for wrought products. O: Annealed. Wrought products are
annealed to achieve lowest-strength temper, and cast products are annealed to
improve ductility and dimensional stability. The O may be followed by a digit
other than zero. H: Strain-hardened (wrought products
only). Strengthened by strain hardening, with or without supplementary
thermal treatment to produce some reduction in strength. The H is always
followed by two or more digits. W: Solution heat-treated. Unstable
temper applicable only to alloys whose strength naturally (spontaneously)
changes at room temperature over a duration of months or even years after
solution heat treatment. The designation is specific only when the period of
natural aging is indicated (for example. Wh). T: Solution heat-treated. Alloys
whose strength is stable within a few weeks of solution heat treatment. The T
is always followed by one or more digits. H1: Strain-hardened only.
Strain-hardened to achieve needed strength without supplementary thermal
treatment. The digit following the H1 indicates the degree of strain
hardening. H2: Strain-hardened and partially
annealed. Strain-hardened more than the required final amount, and then
reduced in strength to the required level by partial annealing. The digit
following the H2 indicates the degree of strain hardening remaining after the
product has been partially annealed. H3: Strain-hardened and stabilized.
Strain-hardened, then mechanical properties are stabilized by a
low-temperature thermal treatment, or as a result of heat introduced during
fabrication. Stabilization usually improves ductility. This designation
applies only to those alloys which, unless stabilized, gradually age-soften
at room temperature. The digit following the H3 indicates the degree of
strain hardening remaining after stabilization. Hx11: Products incur sufficient strain
hardening after final annealing to fail to qualify as O temper, but not so
much or so consistent on amount of strain hardening as to qualify as Hx1
temper. H112: Products may acquire some strain
hardening during working at elevated temperature, and they have mechanical
property limits. W and T designations: The W denotes an unstable temper;
T denotes a stable temper other than F, O, or H. The T is followed by a
number from 1 to 10, each number indicating a specific sequence of basic
treatments. T1: Cooled from an
elevated-temperature shaping process and naturally aged to substantially
stable condition. Not cold worked after and elevated-temperature shaping
process such as casting or extrusion. Mechanical properties have been
stabilized by room-temperature aging. Products are flattened or straightened
after cooling from the shaping process, but the effects of the cold work
imparted by flattening or strainghtening are not accounted for in specified
property limits. T2: Cooled from an
elevated-temperature shaping process, cold worked, and naturally aged to a
substantially stable condition. Cold worked specifically to improve strength
after cooling from a hot-working process such as rolling or extrusion.
Mechanical properties have been stabilized by room-temperature aging. Also
products in which the effects of cold work, imparted by flattening or
straightening, are accounted for in specified property limits. T3: Solution heat treated, cold
worked, and naturally aged to a substantially stable condition. Cold worked
specifically to improve strength after solution heat treatment. Mechanical
properties have been stabilized by room-temperature aging. T3 also includes
products in which the effects of cold work, imparted by flattening or
straightening, are accounted for in specified property limits. T4: Solution heat treated and
naturally aged to a substantially stable condition. Not cold worked after
solution heat treatment, and mechanical properties have been stabilized by
room-temperature aging. If the products are flattened or straightened, the
effects of the cold work imparted by flattening or straightening are not
accounted for in specified property limits. T5: Cooled from an
elevated-temperature shaping process and artificially aged. Not cold worked
after an elevated-temperature shaping process such as casting or extrusion.
Mechanical properties have been substantially improved by precipitation heat
treatment. If the products are flattened or straightened after cooling from
the shaping process, the effects of the cold work imparted by flattening or
straightening are not accounted form in specified property limits. T6: Solution heat treated and
artificially aged. Not cold worked after solution heat treatment. Mechanical
properties or dimensional stability, or both, have been substantially
improved by precipitation heat treatment. If the products are flattened or
straightened, the effects of the cold work imparted by flattening or
straightening are not accounted for in specified property limits. T7: Solution heat treated and
overaged or stabilized. Wrought products precipitation heat treated beyond
the point of maximum strength to provide some special characteristic, such as
enhanced resistance to stress-corrosion cracking or exfoliation corrosion.
Also applies to cast products that are artificially aged after solution heat
treatment to provide dimensional and strength stability. T8: Solution heat treated, cold worked,
and artificially aged. Cold worked specifically to improve strength after
solution heat treatment. Mechanical properties or dimensional stability, or
both, have been substantially improved by precipitation heat treatment. The
effects of cold work, including any cold work imparted by flattening or
straightening, are accounted for in specified property limits. T9: Solution heat treated,
artificially aged, and cold worked. Cold worked specifically to improve
strength after parts have been precipitation heat treated. T10: Cooled form an
elevated-temperature shaping process, cold worked, and artificially aged.
Cold worked specifically to improve strength after cooling from a hot-working
process such as rolling or extrusion. Mechanical properties have been substantially
improved by precipitation heat treatment. The effects of cold work, including
any cold work imparted by flattening or straightening, are accounted for in
specified property limits. |
|
|
Compliments of ASM-International |
|
|
|
|
|
Last Updated: |
Contact the professor at: stoebe@u.washington.edu
|