347 Stainless Steel Sheet, Coil and Bar - AMS 5512, 5646

Inventory Size Ranges for 347

Type	Thickness	AMS Standards	ASTM	UNS	ASME	Get a Quote
Coil	0.020" - 0.125"	AMS 5512, AMS 5646	ASTM A 269, ASTM A 276, ASTM A193	UNS S34700	ASME SA 269, ASME SA 276	Get a Quote
Sheet	0.020" - 0.125"	AMS 5512, AMS 5646	ASTM A 269, ASTM A 276, ASTM A193	UNS S34700	ASME SA 269, ASME SA 276	Get a Quote
Bar	0.375" - 4.000"	AMS 5512, AMS 5646	ASTM A 269, ASTM A 276, ASTM A193	UNS S34700	ASME SA 269, ASME SA 276	Get a Quote
Precision Reroll Strip	0.0008" - 0.015"					Get a Quote

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Characteristics of 347

347 is advantageous for high temperature service, offering high resistance to intergranular corrosion and oxidation at high temperatures. 347 offers similar resistance to general, overall corrosion as the unstabilized chromium nickel Type 304. Heating for long periods of time in the chromium carbide precipitation range may affect the general resistance of Types 347 in severe corrosive media. 347 stainless is preferable for aqueous and other low temperature environments. Exposure in the 800 to 1500°F (427 to 816°C) temperature range lowers the overall corrosion resistance of 321 alloy to a much greater extent than 347 alloy. When the unstabilized chromium-nickel steels are held in or slowly cooled through the range of 800 to 1500°F (427 to 816°C), chromium carbide is precipitated at the grain boundaries. In the presence of certain strongly corrosive media, these grain boundaries are preferentially attacked, a general weakening of the metal results, and a complete disintegration may occur. 

Working with 347

The annealing temperature range for 347 is 1800 to 2000°F (928 to 1093°C). While the primary purpose of annealing is to obtain softness and high ductility, this material may also be stress relief annealed within the carbide precipitation range 800 to 1500°F (427 to 816°C), without any danger of subsequent intergranular corrosion. Relieving strains by annealing for only a few hours in the 800 to 1500°F (427 to 816°C) range will not cause any noticeable lowering in the general corrosion resistance, although prolonged heating within this range does tend to lower the general corrosion resistance to some extent. As emphasized, however, annealing in the 800 to 1500°F (427 to 816°C) temperature range does not result in a susceptibility to intergranular attack. 

347 is susceptible to stress corrosion cracking (SCC) in halides similar to ATI 304 stainless steel. This results because of their similarity in nickel content. Conditions which cause SCC are: (1) presence of halide ion (generally chloride), (2) residual tensile stresses, and (3) environmental temperatures in excess of about 120°F (49°C). Stresses may result from cold deformation during forming operations, or from thermal cycles encountered during welding operations. Stress levels may be reduced by annealing or stress-relieving heat treatments following cold deformation. The stabilized 347 alloy is good choices for service in the stress relieved condition in environments which might otherwise cause intergranular corrosion for unstabilized alloys. 

Austenitic stainless steels are considered to be the most weldable of the high-alloy steels and can be welded by all fusion and resistance welding processes. Two important considerations in producing weld joints in the austenitic stainless steels are preservation of corrosion resistance and avoidance of cracking. Care needs to be exercised to avoid pickup of carbon from oils and other sources and nitrogen from air. Weld practices which include attention to cleanliness and good inert gas shielding are recommended for these stabilized grades as well as other non-stabilized austenitic alloys. Weld metal with a fully austenitic structure is more susceptible to cracking during the welding operation. For this reason, alloy 347 is designed to resolidify with a small amount of ferrite to minimize cracking susceptibility. Columbium stabilized stainless steels are more prone to hot cracking than titanium stabilized stainless steels.