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"Gateway
P-20 MQ/FM" |
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| Prehardened
Mold |
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| Quality
P-20 Modified |
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| Tool
Steel |
Gateway P-20 MQ/FM |
is
supplied in the prehardened condition.
Special melting and |
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refining practices are utilized to
produce a uniform product with exceptional cleanliness. |
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These characteristics allow Gateway
P-20 MQ/FM to be polished to an extremely high finish |
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required for plastic molding. The material is tested to rigorous tool
steel standards to ensure |
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uniformity of structure and freedom
from defects. |
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Gateway P-20 MQ/FM
provides substantially improved machinability |
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while
retaining full capability for plastic mold applications, holder |
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blocks and mechanical
applications. |
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Gateway P-20 MQ/FM |
is
supplied prehardened to 262/321 BHN.
The balanced alloy |
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composition ensures a
very uniform cross-sectional hardness. |
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| Chemistry |
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Carbon |
.36/.42 |
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Manganese |
1.10/1.30 |
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Phosphorus |
.010 max |
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Sulfur |
.010/.022 |
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silicon |
.35/.45 |
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Chromium |
1.00/1.20 |
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Molybdenum |
.15/.35 |
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Nickel |
.25/.50 |
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Oxygen |
.002 max |
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Hydrogen |
.0002 max |
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| Stress
Relief |
Heat
slowly and uniformly to 800/900degrees F, and soak one hour per inch of
section |
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thickness. Air cool or furnace cool to room temperature. |
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| Annealing |
It is recommended that Gateway P-20
MQ/FM be annealed prior to rehardening.
Heat slowly |
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and uniformly to 1500/1600 degrees F
for four hours. Cool slowly (50
degrees F per hour max) |
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to 1200 degrees F, and air cool. |
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| Heat
Treating |
Gateway P-20 MQ/FM may be heat
treated to higher hardness levels for higher strength. |
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Preheat to 1250 degrees F, and hold
one hour. Heat to 1500/1600 degrees
F, and soak one |
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half
hour when material is up to temperature.
Oil quench or air cool to hand warm |
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(approximately 150 degrees F), and
temper immediately. |
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| Tempering |
Temper one hour per inch of section
thickness to desired hardness.
Representative hardness |
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levels after tempering are tabulated
below. |
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Oil Quenched from 1600 degrees F -
Tempered 4 hours |
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(Section Size --- 4" x 4") |
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Tempering |
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Tempering |
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Temperature (F) |
Hardness (RC) |
Temperatures (F) |
Hardness (RC) |
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400 |
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42 |
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900 |
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36 |
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500 |
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41 |
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1000 |
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34 |
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600 |
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40 |
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1100 |
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29 |
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700 |
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39 |
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1200 |
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25 |
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800 |
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37 |
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Note: |
Variations in section size, heating
rate, soak time, quench rate and tempering will |
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cause
deviations from the above values.
Gateway Metals should be consulted for specific |
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applications. |
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(BACK OF FIRST PAGE) |
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| EDM |
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Electro-discharge machining is
widely used in the production of plastic molds and other tooling. |
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However, this operation produces
recast, rehardened, and retempered layers on the die surface. |
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It
is recommended that Gateway P-20 MQ/FM be stress releived after
electro-discharge |
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machining to temper the rehardened
layer produced by EDM. |
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| Nitriding |
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Gateway
P-20 MQ/FM may be nitrided to a surface hardness in excess of RC 60 for
improved |
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wear resistance. |
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