martempering and austempering final slide
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8/16/2019 Martempering and Austempering Final Slide
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MARTEMPERING AND AUSTEMPERING
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STEELS
•can be heat treated to highhardness and strength levels for
getting the required strength forvarious applications.
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• Structural componentssubjected to high operating
stress need the highstrength of a hardenedstructure.
STEELS
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• tools such as dies, knives,cutting devices, and
forming devices need ahardened structure toresist wear and
STEELS
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• Quenched hardened steelsare so brittle that even slight
impacts may cause fracture
STEELS
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• “TEMPERING” to removethe stresses and
brittleness caused byquenching and to develop
the required mechanical
STEELS
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TEMPERING
• a heat treatment thatreduces the brittleness
of steel withoutsignicantly lowering itshardness and strength.
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• !ll hardened steels must
undergone this treatmentbefore use.
TEMPERING
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• Processes:
". #artempering
$. !ustempering%. &onventional 'eat,
Quench and (emper
TEMPERING
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• )#arquenching* is a form of heattreatment applied as aninterrupted quench of steels
typically in a molten salt bath at atemperature right above themartensite start temperature.
MARTEMPERING
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• to delay the cooling for alength of time to equali+e the
temperature throughout thepiece which will minimi+edistortion, cracking and
residual stress.
MARTEMPERING
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--/0(S1• 2educed cracking due to thermal
stress.
• 2educed residual stress in thequenched part section for parts
with varying geometry, si+e, or
MARTEMPERING
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• Since marquenching lowersthe residual thermal stress, it
is used for parts with comple3geometries, diverse weights,and section changes.
MARTEMPERING
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MARTEMPERING
• Quenchingfrom theaustenitising
temperatureto atemperatureabove themartensitic
425&-SS
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MARTEMPERING
• 'olding in the
quenchingmedium untilthe
temperaturethroughoutthe steel issubstantiallyuniform
425&-SS
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MARTEMPERING
•
&ooling at amoderaterate toprevent large
di6erencesbetween theoutside and
the centre of
425&-SS
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MARTEMPERING
• (emperinginconventional
fashion
425&-SS
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AUSTEMPERING
• is a heat treating process formedium8to8high carbon ferrousmetals which produces !00(-structure.
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0t yields desirable mechanicalproperties including1
• 'igher ductility, toughness, and
strength for a given hardness.• 2esistance to shock
• 2educed distortion, specically
with thin parts.
AUSTEMPERING
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•
(his process is widely used inthe automotive industry forclips and other parts where
ma3imum 9e3ibility andtoughness are required.
AUSTEMPERING
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AUSTEMPERING425&-SS
• 'eating to
atemperature within
theaustenitising range,
usually
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• Quenched in a
bath )moltensalt, oroccasionally oil*maintained at a
constanttemperature,usually in the
range of $@<=8
%:<=& )><<8=
AUSTEMPERING425&-SS
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•'eld for atime to allowtransformationto a bainitemicrostructure
AUSTEMPERING425&-SS
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•
&ooled toroomtemperature.
AUSTEMPERING425&-SS
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MANA