Product Details

Product Description

astm a240 304l stainless steel plate

Brief introduction

Grade 304 is the standard "18/8" stainless; it is the most versatile and most widely used stainless steel, available in a wider range of products, forms and finishes than any other. It has excellent forming and welding characteristics. The balanced austenitic structure of Grade 304 enables it to be severely deep drawn without intermediate annealing, which has made this grade dominant in the manufacture of drawn stainless parts such as sinks, hollow-ware and saucepans.

Grade 304L, the low carbon version of 304, does not require post-weld annealing and so is extensively used in heavy gauge components (over about 6mm). Grade 304H with its higher carbon content finds application at elevated temperatures. The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures.

Key Properties

These properties are specified for flat rolled product (plate, sheet and coil) in ASTM A240/A240M. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications.

Composition

Table 1. Composition ranges for 304 grade stainless steel

Grade

304

min.

max.

0.08

2.0

0.75

0.045

0.030

18.0

20.0

8.0

10.5

0.10

304L

min.

max.

0.030

2.0

0.75

0.045

0.030

18.0

20.0

8.0

12.0

0.10

Mechanical Properties

Table 2. Mechanical properties of 304 grade stainless steel

Grade	Tensile Strength (MPa) min	Yield Strength 0.2% Proof (MPa) min	Elongation (% in 50mm) min	Hardness
Grade	Tensile Strength (MPa) min	Yield Strength 0.2% Proof (MPa) min	Elongation (% in 50mm) min	Rockwell B (HR B) max	Brinell (HB) max
304	515	205	40	92	201
304L	485	170	40	92	201

Physical Properties

Table 3. Physical properties of 304 grade stainless steel in the annealed condition

Grade	Density (kg/m³)	Elastic Modulus (GPa)	Mean Coefficient of Thermal Expansion (mm/m/°C)				Thermal Conductivity (W/m.K)		Specific Heat 0-100^°C (J/kg.K)
Grade	Density (kg/m³)	Elastic Modulus (GPa)	0-100°C	0-315°C	0-538°C	0-649°C	at 100°C	at 500°C	Specific Heat 0-100^°C (J/kg.K)
304/L	8000	193	17.2	17.8	18.4	18.7	16.2	21.5	500

Electrical Resistivity (nW.m)

Magnetic Permeability, H = 200

Oersteds, Annealed

Melting Range

720

1.02 max.

1399-1454 (°C)

Heat Resistance

Good oxidation resistance in intermittent service to 870°C and in continuous service to 925°C. Continuous use of 304 in the 425-860°C range is not recommended if subsequent aqueous corrosion resistance is important. Grade 304L is more resistant to carbide precipitation and can be heated into the above temperature range.

Heat Treatment

Solution Treatment (Annealing) - Heat to 1010-1120°C and cool rapidly. These grades cannot be hardened by thermal treatment.Stress Relief Annealing: Cold worked parts should be stress relieved at 750°F (399°C) for 1/2to 2 hours.

Welding

Excellent weldability by all standard fusion methods, both with and without filler metals. AS 1554.6 pre-qualifies welding of 304 with Grade 308 and 304L with 308L rods or electrodes (and with their high silicon equivalents). Heavy welded sections in Grade 304 may require post-weld annealing for maximum corrosion resistance. This is not required for Grade 304L. Grade 321 may also be used as an alternative to 304 if heavy section welding is required and post-weld heat treatment is not possible.