SUS321 Stainless Steel: Titanium-Stabilized Welding Grade

Grade 321H is a modification of 321 with higher carbon content, to provide improved high-temperature strength.

 

A limitation with 321 is that titanium does not transfer well across a high-temperature arc, so it is not recommended as a welding consumable. In this case grade 347 is preferred - the niobium performs the same carbide stabilization task but can be transferred across a welding arc. Grade 347 is, therefore, the standard consumable for welding 321. Grade 347 is only occasionally used as parent plate material.

 

Like other austenitic grades, 321 and 347 have excellent forming and welding characteristics, are readily brake or roll-formed and have outstanding welding characteristics. Post-weld annealing is not required. They also have excellent toughness, even down to cryogenic temperatures. Grade 321 does not polish well, so is not recommended for decorative applications.

 

Grade 304L is more readily available in most product forms, and so is generally used in preference to 321 if the requirement is simply for resistance to intergranular corrosion after welding. However, 304L has lower hot strength than 321 and so is not the best choice if the requirement is resistance to an operating environment over about 500 °C.

 

Grade		C	Mn	Si	P	S	Cr	Mo	Ni	N	Other
321	min. max	- 0.08	2.00	0.75	0.045	0.030	17.0 19.0	-	9.0 12.0	0.10	Ti=5(C+N) 0.70
321H	min. max	0.04 0.10	2.00	0.75	0.045	0.030	17.0 19.0	-	9.0 12.0	-	Ti=4(C+N) 0.70
347	min. max	0.08	2.00	0.75	0.045	0.030	17.0 19.0	-	9.0 13.0	-	Nb=10(C+N) 1.0