Stainless Steel 304 vs 304L

Asia’s most complete stainless steel grades center locate at Malaysia . we do stock & supply high performance stainless steel to Asia Market with Air Freight / Ocean Freight capable to received in shorter lead time.

300 series Stainless Steel : 253MA,SUS301,SUS303,SUS304,SUS304L,SUS304H,SUS309,SUS310,SUS316,SUS316L,SUS316Ti,SUS317,SUS321,SUS347.

400 series Stainless Steel : SUS403,SUS409,SUS410,SUS416,SUS420,SUS420J2,SUS430,SUS430F,SUS431,SUS440C, F6NM, SUS446,SUS630,SUS660, 15-5PH,17-4PH,904L )

Duplex Stainless steel : FERRALIUM 255, S31803, S32750, S32760 , S31254 , S329J4L 

Nitronic 30, 50 & 60

Description

Stainless Steel 304 (UNS S30400), SUS304, ss304

sus304 Chemical Composition

Fe, <0.08% C, 17.5-20% Cr, 8-11% Ni, <2% Mn, <1% Si, <0.045% P, <0.03% S

What is SUS304 stainless steel?
refers to the composition of the stainless steel and also refer to the amount of chromium and nickel in the product. “SS” is short for “Stainless Steel”, “SS304” is short for “Stainless Steel 304”. SUS304 means 304 stainless steel under Japanese standard.

Background

SUS304 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. For these applications it is common to use special “304DDQ” (Deep Drawing Quality) variants. Grade 304 is readily brake or roll formed into a variety of components for applications in the industrial, architectural, and transportation fields. Grade 304 also has outstanding welding characteristics. Post-weld annealing is not required when welding thin sections.

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.

 

Composition of SUS304 VS SUS304L

Grade C Mn Si P S Cr Mo Ni N
SUS304 min.

max.

0.08

2.0

0.75

0.045

0.030

18.0

20.0

8.0

10.5

0.10

SUS304L min.

max.

0.030

2.0

0.75

0.045

0.030

18.0

20.0

8.0

12.0

0.10

Mechanical Properties of SS304 VS 304L

Grade Tensile Strength (MPa) min Yield Strength 0.2% Proof (MPa) min Elongation (% in 50mm) min Hardness
Rockwell B (HR B) max Brinell (HB) max
SS304 515 205 40 92 201
SS304L 485 170 40 92 201

Physical Properties

Grade Density (kg/m3) Elastic Modulus (GPa) Mean Coefficient of Thermal Expansion (μm/m/°C) Thermal Conductivity (W/m.K) Specific Heat 0-100°C (J/kg.K) Electrical Resistivity (nΩ.m)
0-100°C 0-315°C 0-538°C at 100°C at 500°C
304/L/H 8000 193 17.2 17.8 18.4 16.2 21.5 500 720

 

Corrosion Resistance

Excellent in a wide range of atmospheric environments and many corrosive media. Subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 60°C. Considered resistant to potable water with up to about 200mg/L chlorides at ambient temperatures, reducing to about 150mg/L at 60°C.

Heat Resistance

Good oxidation resistance in intermittent service to 870°C and in continuous service to 925°C. Continuous use of SUS304 in the 425-860°C range is not recommended if subsequent aqueous corrosion resistance is important. SUS304L is more resistant to carbide precipitation and can be heated into the above temperature range.

SUS 304H has higher strength at elevated temperatures so is often used for structural and pressure-containing applications at temperatures above about 500°C and up to about 800°C. SUS304H will become sensitised in the temperature range of 425-860°C; this is not a problem for high temperature applications, but will result in reduced aqueous corrosion resistance.

 

Dual Certification

It is common for SS304 and SS304L to be stocked in “Dual Certified” form, particularly in plate and pipe. These items have chemical and mechanical properties complying with both SS304 and SS304L specifications. Such dual certified product does not meet Ss304H specifications and may be unacceptable for high temperature applications.

What is the highest grade stainless?
300 series is the largest group and the most widely used. Type 304: The best-known grade is Type 304, also known as 18/8 and 18/10 for its composition of 18% chromium and 8%/10% nickel, respectively.
Can stainless steel rust?
Stainless steel remains stainless, or does not rust, because of the interaction between its alloying elements and the environment. Stainless steel contains iron, chromium, manganese, silicon, carbon and, in many cases, significant amounts of nickel and molybdenum.