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Q: |
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What is sinter-hardening? |
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A: |
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Sinter-hardening refers to a
process where the cooling rate experienced in the cooling zone of the sintering furnace is
fast enough that a significant portion of the steel matrix is transformed into martensite.
The benefits of sinter-hardening are:
- Eliminates the need for secondary
heat treatment
- Improved part dimensional control
(reduced distortion)
- Easier tempering in air because of
the elimination of oil-quenching
- Sinter-hardened parts do not need
oil removal prior o finishing operations such as plating
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Q: |
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What base powders are typically
used for sinter-hardening? |
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A: |
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- Ancorsteel 4600V + 2 w/o Cu + 0.9
w/o graphite
- Ancorsteel 150 HP + 2 w/o Cu + 0.9
w/o graphite
- Ancorsteel 150 HP + 2 w/o Ni + 1 w/o
Cu + 0.6 w/o graphite
- Ancorsteel 85 HP + 2 w/o Ni + 1 w/o
Cu + 0.9 w/o graphite
- Ancorsteel 2000 + 2 w/o Cu + 0.9 w/o
graphite
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Q: |
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Why would one of these materials
be used rather than another of those shown in the examples? |
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A: |
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Material compositions are chosen
by application requirements. In general:
1) most hardenable -> 5) least hardenable |
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Q: |
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What are the typical cooling rates
required? |
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A: |
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Cooling rate depends upon the
material composition, but, in general, it is recommended to have a cooling rate of
0.9°F/sec (0.5°C/sec) or greater between 1200°F (649°C) and 380°F (193°C). |