304H

Type	Seamless & Welded Pipe	Butt Weld Fittings	Flanges & Pressure Fittings
Sizes	1/4″ thru 16″	1/2″ thru 12″	All descriptions
Schedules	10, 40, 80, 160 & XXH	10, 40, 80, 160 & XXH	All descriptions

ASTM Standards

Bar	Butt Weld Fittings	Forgings	Pipe, Welded & Seamless	Tube, Welded	Tube, Seamless	Plate
A 276, A479	A403	A182	A312	A249	A213	A240

Minimum Physical Properties

Tensile Strength	Yield Strength	Elongation	Hardness
75 KSI / 515 MPA	30 KSI / 205 MPA	40% Min.	RB 92 Max.

Chemical Composition (wt%)

C	Mn	P	S	Si	Ni	Cr	Fe
0.04 – 0.10	2.00 Max	0.045 Max	0.03 Max	1.00 Max	8.0 – 11.0	18.0 – 20.0	Balance

Properties

304L is probably the world’s most common stainless steel. The “L” stands for “Low” and refers to the carbon content. 0.035 percent is the maximum allowable carbon content in 304L grade. The “H” in 304H stands for “High” carbon content. 304H must contain not less than 0.04 percent carbon, nor more than 0.10 percent.

The higher carbon content of 304H increases its strength, so the ASTM tensile and yield strength of 304H is greater than 304L.

304H has greater short term and long term creep strength than 304L at temperatures up to 500 degrees C, and 304H is more resistant to sensitization than 304L.

In ASME pressure vessels for use above 525 degrees C, the carbon content of 304 stainless must be 4 percent or more. 304H is required in such applications.

Applications

304H is most commonly used in petroleum refineries. It is also found in boilers. Other applications include heat exchangers, condensers, pipelines, cooling towers, steam exhausts, and electric generation plants. On occasion it will also be found in fertilizer and chemical plants.

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