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AISI 4140 HEAT TREATED
SUPER BRAKE DIE
Super Brake Die is quality alloy steel supplied in the prehardened condition. Special
melting and refining practices are utilized to produce a uniform product with exceptional
cleanliness. The material is tested to rigorous tool steel standards to ensure uniformity
of structure and freedom from defects. Super Brake Die is supplied prehardened to
262/321 BHN. Super Brake Die is available premachined oversize on thickness
and saw-cut to the customer’s exact specifications.
ANALYSIS
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Carbon
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.40/.42
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Manganese
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.85/.95
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Sulfur
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.020 Max
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Silicon
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.30/.45
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Molybdenum
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.20/25
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Phosphorus
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.035 Max
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Chromium
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.90/1.00
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SIZE AVAILABILITY
Flats - Rounds - Squares - Hollowbar
Standard Sizes - Non-Standard Sizes - Metric Sizes
STRESS RELIEF
Heat slowly and uniformly to 1000° F and soak one hour per inch of
section thickness. Air cool or furnace cool to room temperature.
ANNEALING
It is recommended that Super Brake Die be annealed prior to rehardening.
Heat slowly and uniformly to 1500/1600°F for four hours. Cool slowly (50°
F per hour max) to 1200° F and air cool.
HEAT TREATING
Super Brake Die may be heat-treated to higher hardness levels for higher
strength. Preheat to 1250° F and hold one hour. Heat to 1550/1600° F and
soak one half hour when material is up to temperature. Oil quench or air cool to
hand warm (approximately 150° F) and temper immediately.
NITRIDING
Super Brake Die may be nitrided to a surface hardness in excess of RC 60
for improved wear resistance.
TEMPERING
Temper one hour per inch of section thickness to desired hardness. Representative
hardness levels after tempering are tabulated below:
Oil Quenched from 1600° F – Tempered 4 hours
(Section Size – 4”x4”
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Tempering Temperature (° F)
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Hardness
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Tempering Temperature (° F)
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Hardness
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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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Note: Variations in section size, heating rate, soak time, quench and tempering
will cause deviations from the above values. Diehl Steel should be consulted for
specific applications.
EDM
Electro-discharge machining is widely used in the production of plastic
molds and other tooling. However, this operation produces recast, rehardened and
retempered layers on the die surface. It is recommended that Super Brake Die be
stress relieved after electro-discharge machining to temper the rehardened layer
produced by EDM.
MACHINING DATA
Normalized and Tempered
Brinell 262/321
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Operation
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Depth of Cut
(in)
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High Speed Tooling
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Carbide Tooling
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Speed
(fpm)
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Feed
(in/rev)
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Speed
( fpm)
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Feed
(in/rev)
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Drilling
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1/8
1/4
1/2
1
2
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45
45
45
45
45
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.002
.004
.006
.009
.015
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Gun Drilling
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1/4
1/2
1
2
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165
165
165
165
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.0005
.0008
.0015
.002
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Single Point Tuming
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.040
.150
.300
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90
70
55
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.007
.015
.020
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440
340
270
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.007
.015
.020
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Cut Off
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.062
.125
.250
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55
55
55
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.0013
.0016
.002
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Face Milling
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.040
.150
.300
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105
85
65
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.006*
.009*
.012*
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485
375
290
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-006*
.008*
.010*
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*Feed in inches per tooth.
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