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PRODUCT DATA of AISI 347
MaterialAISI 347
General InformationType 347 is a niobium/tantalum stabilized austenitic chromium-nickel stainless steel which was developed to improve intergranular-corrosion resistance. it is stabilized against chromium carbide formation by the addition of niobium and tantalum. Since niobium and tantalum have a stronger affinity for carbon than chromium, niobiumtantalum carbides precipitate within the grains instead of forming at the grain boundaries.
PrecautionsAlthough the alloy is resistant to sensitization and associated intergranualr corrosion, its general corrosion resistance is slightly lowered by prolonged exposures in the sensitization range of 425 to 870 C
Effects of Space environmentThe natural oxide layer is not repaired in vacuum when damaged. Cold welding might occur in contact to similar materials
Chemical Composition17-19Cr, 9-13Ni,<2Mn, <0.08C, (10xC)Nb-Ta min, rem Fe
EXPERIENCE IN PRACTICE
Development StatusCommercial Product
Cost RangeLow
Lot ReproducibilityGood
Equivalent DesignationsS30347, 1.4550, X10,CrNiNb189, 347S17
Space ExperienceGood
PHYSICAL PROPERTIES
Crystal StructureFace centered cubic (fcc)
Specific Gravity7.96
Magnetic PropertiesNonmagnetic
ELASTIC PROPERTIES
Tensile Modulus195 GPa
Shear Modulus77 GPa
Poisson Ratio0.27
THERMAL PROPERTIES
Thermal Conductivity16.3 W/m.K
Thermal Expansion Coefficient17.3 μstrain/°C
Melting Range1400 to 1430 °C
Specific Heat0.5 J/g.K
RELEVANT PROPERTIES FOR USE IN SPACE COMMUNITY
General Corrosion StatusNo specific corrosion protection required
Stress Corrosion StatusHigh Resistance to SCC: Table 1
Remark: acc. to ECSS-Q-ST-70-36C
Data Quality: Design Data
EMF vs SCE-0.08 V
Remark: Measured in 3.5% NaCl solution. Passive condition
Data Quality: Design Data
FLUID SYSTEMS COMPATIBILITY
Gaseous Oxygen (GOX)Meets the mechanical impact requirements. No batch test required.
Liquid Oxygen (LOX)Meets the mechanical impact requirements. No batch test required.
Nitrogen Tetroxide (N2O4)SCC susceptibility is low and no fluid decomposition
Hydrazine (HDZE)SCC susceptibility is low and no fluid decomposition