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Custom 455

Alloy 455 is an alloy melted by several sources. Custom 455® is a trademarked name of Carpenter Specialty Alloys. It is a martensitic age-hardenable stainless steel that offers a unique set of qualities. This alloy is double vacuum-melted using a Vacuum Induction Melt (VIM) followed by a Vacuum Arc Remelt (VAR).


Chemistry
  AMS 5617G #1
Carbon 0.03
Manganese 0.5
Silicon 0.5
Phosphorus 0.015
Sulfur 0.015
Chromium 11.0-12.5
Nickel 7.5-9.5
Molybdenum 0.5
Copper 1.5-2.5
Titanium 0.9-1.4
Iron Balance
Nitrogen 0.015
Columbium 0.50

Physical Properties
Density 0.280 lbs/in3
Modulus Of Elasticity 29.0 psi x 106
Electrical Resistivity 758 µohms-mm
Thermal Conductivity 18.0 W/mK (100°C)

Thermal Treatment

A reducing atmosphere is preferred for thermal treatment, but inert gas can be used. Alloy 455 will fully anneal at 950-980°C in just a few minutes. Alloy 455 can minimally age harden with a loss in ductility, when held for prolonged periods at 370C-540°C. Original hardness can be restored by heating at 590°C.


Applications

Alloy 455 is a great material in that you can fabricate a part from material at a lower ultimate tensile strength and then heat treat it to a much higher strength. Unlike many other heat treatable alloys, Alloy 455 has good oxidation resistance at room temperature. Primary end applications are: needles, stylets, pins and springs.


Mechanical Properties
%CW Y.S.(psi) % Elongation
(10" gauge length)
0% 145,000 6.3%
20% 153,000 5.7%
37% 161,000 3.8%
50% 165,000 3.5%
60% 173,000 4.6%
68% 185,000 2.4%
75% 190,000 2.5%
80% 193,000 2.6%
84% 199,000 2.6%
87% 210,000 2.2%
90% 220,000 2.5%
92% 230,000 2.4%

Values are typical and may not represent all diameters. Test method will affect results.


Surface Condition

Stainless steels develop a highly polished appearance as they are drawn to fine diameters. Surface roughness can be less than 5 RMS when processed using SCND* dies and measured with a profilometer. Diameters over 0.040" are finished with polycrystalline dies and exhibit a rougher surface than natural diamond dies. Diameters over 0.100" will have an even rougher surface because they are drawn with carbide dies.

*SCND means single crystal natural diamond.