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General |
Applications |
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RoyAlloy™ is a 400 series
martensitic stainless steel supplied prehardened. RoyAlloy™
is characterized by:
- Excellent machinability
- Good corrosion resistance
- Uniform and consistent hardness in
all dimensions
- Good resistance to indentation
(compressive strength)
- Excellent ductility
- Excellent flatness
- Dimensionally stable
- Smooth as rolled surfaces
- Excellent weldability
- Good thermal conductivity
RoyAlloy™ is an
improved stainless grade designed specifically for plastic molding
applications. Chemical composition and thermal treatments provide physical
properties and microstructures designed to provide:
- Reduced mold maintenance
costs
- Worry free weld repair
- Dimensional stability
- Lower mold production costs due to
less cutting tool wear and increased cutting speeds
RoyAlloy™ was developed by EDRO to provide superior performance in all important areas of manufacturing and operation for the plastic and rubber mold tooling industries. Extensive machining trials have shown that this material is readily machined, provides excellent surface finishes and thread quality. Special production procedures provide superior surface quality and flatness. Bend tests have demonstrated that this material can tolerate moderate amounts of cold flattening without breakage. Heat treating and microstructure of the material provides excellent dimensional stability after machining, without the need for stress relieving or excess stock oversize. RoyAlloy™ is also suitable for texturing and photoetching.
RoyAlloy™ is available from stock in flat sizes up to 12" thick and rounds up to 12" diameter.
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- Plastic and rubber molds
- Plastic mold bases
- Plastic mold inserts
- Constructional parts
- Plastic extrusion
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Physical Data
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Prehardened to 321 HB, Data at room and elevated temperatures.
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Temperature
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68°F
(20°C)
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390°F
(200°C)
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Density,
kg/m3
lbs/in3
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7,800
.282
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7,750
.280
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Modulus of
elasticity
N/mm2
psi
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200,000
29.0 X 108
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190,000
27.6 x 106
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Coefficient of thermal
expansion
per °F from 68°F
per °C from 20°C
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—
—
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6.1 x 10-6
11.0 x 10-6
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Tensile Strength
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Longitudinal Tests from 3" (76mm) rolled plate at 321 HB
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Testing
Temperature
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68°F
(20°C)
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390°F
(200°C)
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Ultimate Tensile
strength,
psi
N/mm2
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155 000
1069
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152 000
1048
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Yeild strength @ .2%
offset,
psi
N/mm2
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129 000
890
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126 000
869
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% Elongation in
2"
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12
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12
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% Reduction in
Area
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34
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34
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Impact Strength
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Longitudinal Charpy V-notch Tests from a 3" (76mm) rolled plate
at 321 HB
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Testing
Temperature
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68°F
(20°C)
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390°F
(200°C)
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Ft-lbs
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16
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26
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Joules
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22
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36
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Heat Treatment |
Corrosion Resistance
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RoyAlloy™ is provided pre-hardened to approximately 321 Brinell.
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Tooling made from RoyAlloy™ will have excellent resistance to rusting caused by corrosive plastic elements, and humid working and storage conditions, which may be encountered under normal molding production conditions.
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Welding |
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RoyAlloy™ is readily weldable without pre or post heating.
Documented testing has shown that
RoyAlloy™ does not develop an over-hardened heat affected zone
(HAZ) surrounding the weld deposit. This eliminates the risk of weld induced
cracking during repairs or in future service.
For best results special RoyAlloy™ welding electrodes,
available from EDRO, should be used. RoyAlloy™ electrodes will provide optimal chemical and mechanical
properties, in order to match the filler with the base metal.
Alternatively, processes such as GMAW and SMAW may be employed, using several standard stainless filler metals. However, welding with dissimilar materials may cause a galvanic reaction, which could lead to localized corrosion. This can be attributed to a chemical mismatch between the filler metals and the base steel.
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