409 Stainless Steel

Type 409 Stainless Steel is covered by the following specifications:ASTM A240/A240M.

Chemical Composition:

Element	UNS S40910	UNS S40920	UNS S40930
Carbon	0.030 max.	0.030 max.	0.030 max
Manganese	1.00 max.	1.00 max.	1.00 max.
Sulfur	0.020 max.	0.020 max	0.020 max
Phosphorus	0.040 max.	0.040 max.	0.040 max.
Silicon	1.00 max.	1.00 max.	1.00 max.
Chromium	10.5 – 11.7	10.5 – 11.7	10.5 – 11.7
Nickel	0.50 max.	0.50 max.	0.50 max.
Nitrogen	0.030 max.	0.030 max.	0.030 max.
Titanium	6x(C+N) min. – 0.50 max.	8X(C+N)min. / 0.15 – 0.50	0.05 min.
Niobium	0.17 max.	0.10 max.
Ti + Nb			[0.08+8x(C+N)] min. – 0.75 max.

Mechanical Properties:

Type	Yield Strength 0.2% offset (KSI)	Tensile Strength (KSI)	% Elongation (2" Gauge length)	Hardness Rockwell
S40910	25 min.	55 min	20 min.	HRB 88 max.
S40920	25 min.	55 min.	20 min.	HRB 88 max.
S40930	25 min.	55 min.	20 min.	HRB 88 max.

Fabrication

409 Stainless Steels provide good fabricating characteristics and can be cut, blanked and formed without difficulty. These steels provide fabricating characteristics that are much improved when compared to standard ASTM A240 Type 409 stainless steel. Brakes and presses used normally on carbon steel can be used on 409 Stainless Steels.

Welding
409 stainless is readily welded by arc welding processes. When gauge thickness and weld joint geometry permit the use of gas shielded metal-arc welding, joints having good properties are easily obtained. The electrode wires most often suggested are AWS ER309 or ER308L austenitic stainless steel when the application does not include exposure to high temperatures. AWS ER309 or ER308L stainless wire may also be employed for joining these stainless steels to mild steel. Thin wall components for elevated-temperature service should be weld fabricated with a matching weld filler such as 409 Cb. AWS ER430 and W18 Cr-Cb filler wires are suitable alternatives.