Ford F-150 2015 Structural Repair Training Course page 28

Textbook
Thermal￿paint,￿thermal￿stickers,￿temperature
crayons,￿and￿a￿noncontact￿thermometer￿are￿used￿to
monitor￿heat.
Heat￿may￿be￿used￿to￿temporarily￿soften
and￿help￿straighten￿the￿aluminum￿while
reducing￿the￿possibility￿of￿cracking.￿There
is￿no￿cumulative￿time￿limit￿when￿heating
aluminum,￿only￿temperature￿ranges.
If￿heat￿is￿being￿used,￿do￿not
exceed￿the￿vehicle￿maker's￿heating
recommendations.￿Per￿Ford's￿rule,
temperatures￿should￿not￿exceed￿425°F.
Temperature￿Window,￿Heat￿Indicators,
And￿Cumulative￿Times
When￿considering￿the￿use￿of￿heat,￿it
is￿important￿to￿know￿the￿temperature
window￿to￿work￿within.
When￿the￿temperature￿window￿is
known,￿the￿use￿of￿heat￿indicators,￿such
as,￿thermal￿paint,￿thermal￿stickers,
temperature crayons,￿and￿noncontact
thermometers￿can￿be￿used￿to￿monitor
heating￿temperatures.
Annealing
2015￿Ford￿F-150￿Structural￿Repair￿Training￿Course￿(FOR06)
If￿the￿part￿is￿heated￿beyond￿the￿vehicle
maker￿temperature￿limit,￿the￿area￿being
heated￿may￿become￿permanently￿softened
or￿annealed.
Emissivity
If￿a￿noncontact￿thermometer￿is￿being￿used
on￿bare￿aluminum,￿emissivity￿will￿cause
an￿inaccurate￿temperature￿reading.￿To
compensate￿for￿this,￿the￿surface￿of￿the
panel￿needs￿to￿be￿nonreflective.￿Paint￿or
tape￿can￿be￿applied￿to￿the￿surface￿being
monitored￿for￿an￿accurate￿reading.
Color￿Change,￿Melting￿Point,￿And￿Heat
Transfer
When￿heating￿aluminum,￿it:
does￿not￿change￿color￿before
•
reaching￿its￿melting￿point.
has￿a￿melting￿point￿of
•
approximately￿1,200°F.
has￿a￿very￿high￿rate￿of￿heat￿/
•
thermal￿transfer.￿Aluminum￿will
transfer￿heat￿efficiently￿across￿the
panel,￿about￿three￿times￿faster￿as
compared￿to￿steel.
Module￿2￿-￿Aluminum
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