Stainless Steel 304L (UNS S30400)

SPECIFICATIONS: GRADE 304 / 304L | UNS S30400 / 30403 | ASTM/ASME A240 | Werkstoff 1.4301 / 07

304L is one of the most widely used and versatile stainless steel pipes, Stainless Steel Pipe Fittings and Stainless Steel Flanges at wilsonpipeline Pipe Industry Co., Limited is certified to 304/304L. We are a supplier who can provide stainless steel 304L from stock in sheet, plate, or bar direct from our warehouse and distribute it meeting all cutting and profiling requirements across the world.

This stainless steel grade is found in a variety of commercial sectors, particularly in the chemical industry. It is a sort after material for use in severely corrosive conditions, it is used in heavy gauge components for improved weldability, weld annealing is only necessary in applications where stress loads are excessive.

304L Stainless Steel is characterised by:

• Basic corrosion resistance
• Resistance against intergranular corrosion
• High ductility

Technical information:

Stainless steel 304L is an 18Cr-9Ni austenitic stainless steel. The grade contains small amount of ferrite (≈ 3%) after solution annealing (1000-1100°C – 1832-2012°F) and water quenching.

This kind of steel is one of the basic grades of the stainless steels range. Its low carbon content ensures better ductility and avoids the intergranular corrosion, even on welded pieces without ulterior water quenching.

Stainless steel 304L exhibits austenitic microstructures free of deleterious carbide precipitations at grain boundaries.

Typical values (weight %)
C	Cr	NI	Mo	N	Others
0.020	18.5	9.2	–	0.05	–
PREN (%Cr+3.3%Mo+16%N) ≥ 18

Nickel content may be modified to be conform to 1.4306 grade.

Tensile properties after water quenching
°C	°F	Minimum guaranteed values *						Typical values						El %
		Y.S. 0.2%		Y.S. 1%		UTS		Y.S. 0.2%		Y.S. 1%		UTS
		MPa	Ksi	MPa	Ksi	MPa	Ksi	MPa	Ksi	MPa	Ksi	MPa	Ksi
20	68	200	29	240	35	520/ 650	75/ 95	265	38	305	44	570	83	45
100	212	147	21	181	26	410	60	240	34	280	40	480	70	40
200	392	115	17	147	21	360	52	220	32	240	34	440	63	35
300	572	100	15	127	19	340	50	170	25	190	27	420	62	35
400	752	89	13	116	17	330	48	150	22	165	24	400	58	30
500	932	81	12	109	16	320	47	130	20	145	21	380	56	30

* Following EN 10088 hot rolled plates – The EN guaranteed values are valid for a thickness from 5-75mm. Mechanical properties are related to the thickness of the plate.

Impact values: KCV ≥ 120 j/cm² (room temperature)
°C	-196	-20	+20	θ (°C)	200	400	600
°F	-321	-4	68	θ (°F)	392	752	1112
KCV (J/cm²) Minimum	125	160	180	Ageing H	265	257	252
KCV (J/cm²) Typical	220	250	250	KCU (J/cm²) Transverse	158	142	122

Typical values

High toughness values at -269°C (-452°F) need specific melts (extra low ferrite content).

Interval temper °C	Thermal expansion αx10-6K-1	°C	°F	Resistivity (µΩ cm)	Thermal conductivity (W.m-1.K-1)	Specific heat (J.kg-1.K-1)	Young modulus E (GPa)	Shear modulus G (GPa)
20-100	16	20	68	73	15	500	200	77
20-200	17	100	212	77	16	500	194	75
20-300	17	200	392	84	17.5	520	186	71
20-400	18	300	572	91	19	530	179	68
20-500	18	400	752	97	20.5	540	172	65
		500	932	102	22	540	165	62

Quality corrosion tests guaranteed (special request may be discussed)
TEST	Other name	Corrosion (1)	Results
ASTM A 262 A		Intergranular	Step or dual structure
ASTM A 262 B	STREICHER	Intergranular	Not recommended
ASTM A 262 C	HUEY	Intergranular	< 0,6mm/year*
ASTM A 262 E DIN 50914	STRAUSS	Intergranular	No cracking after bending
ASTM G48 A		Pitting	Not recommended (typical CPT = 5°C-41°F)
ASTM G48 B	ASTM G78	Crevice	Not recommended (typical CCT ≤ 0°C-32°F)

(1) kind of corrosion mechanism investigated

* Using low ferrite grade.

The alloy is not really resistant to localised corrosion in chloride containing solutions. Pitting may occur even at low temperature (5-10°C – 41-50°F).

The alloy is very prone to stress corrosion cracking in chloride containing solution when temperature is higher than 50°C (122°F).

Stainless steel 304L is corrosion resistant in:

• Urban media
• Nitric solution, up to 55% weight, up to 80°C (176°F) (low ferrite)
• Most of diluted organic acids at moderate temperatures
• Most of food and pharmaceutical products
• Pure phosphoric acid
  • Whatever concentration in cold solution
  • Up to 10% diluted hot solution sulphuric or fluoridric acid traces increase the corrosion
• Caustic solutions free of chlorides or fluorides at medium temperatures

The alloys are not corrosion resistant in chloride containing solutions, even diluted, and in sulphuric acid media.

So, the main applications are:

• Food processing industry (excluding Cl – containing media)
• Diluted nitric acid solution
• Nuclear industry (special melts; please consult)

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