321 Stainless Steel - AMS 5510, AMS 5645

Inventory Size Ranges for 321

Type	Thickness	AMS Standards	ASTM	UNS	ASME	Get a Quote
Coil	0.012" - 0.125"	AMS 5510, AMS 5645	ASTM A 167, ASTM A 240, ASTM A 276, ASTM A 479	UNS S32100, UNS S32109	ASME SA 167, ASME SA 240	Get a Quote
Sheet	0.012" - 0.125"	AMS 5510, AMS 5645	ASTM A 167, ASTM A 240, ASTM A 276, ASTM A 479	UNS S32100, UNS S32109	ASME SA 167, ASME SA 240	Get a Quote
Plate	0.1875" - 0.250"	AMS 5510, AMS 5645	ASTM A 167, ASTM A 240, ASTM A 276, ASTM A 479	UNS S32100, UNS S32109	ASME SA 167, ASME SA 240	Get a Quote
Bar	0.375" - 9.000"	AMS 5510, AMS 5645	ASTM A 167, ASTM A 240, ASTM A 276, ASTM A 479	UNS S32100, UNS S32109	ASME SA 167, ASME SA 240	Get a Quote
Hex Bar	0.250" - 1.125"	AMS 5510, AMS 5645	ASTM A 167, ASTM A 240, ASTM A 276, ASTM A 479	UNS S32100, UNS S32109	ASME SA 167, ASME SA 240	Get a Quote
Precision Reroll Strip	0.0008" - 0.015"					Get a Quote

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Characteristics of 321 

321 stainless steels offers similar resistance to general, overall corrosion as the unstabilized chromium-nickel 304 stainless. Heating for long periods of time in the chromium carbide precipitation range may affect the general resistance of 321 stainless in severe corrosion media. 321 alloy in the annealed condition is somewhat less resistant to general corrosion in strongly oxidizing environments compared to annealed 347. For this reason, 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 321

The annealing temperature range for 321 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. For maximum ductility, the higher annealing range of 1800 to 2000°F (928 to 1093°C) is recommended. When fabricating chromium-nickel stainless steel into equipment requiring the maximum protection against carbide precipitation obtainable through use of a stabilized grade, it is essential to recognize that there is a difference between the stabilizing ability of columbium and titanium.

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. It is important to maintain the level of stabilizing element present in 231 alloy during welding, as this alloy is more prone to loss of titanium.  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 this grade 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 321 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. 

Purchasing 321 

We are suppliers of 321 stainless steel sheet, coil, hex bar, and round bar stock in a variety of lengths and widths, and we can custom cut this material to your exact specifications. Our stainless steel coil can also be slit to your desired width.