SUS304 vs SS304 Stainless steel

What is SUS304 and SS 304 ?

SUS 304 Stainless steel austenite is generally referred to as the Japanese name for stainless steel SS304 or AISI 304. Except that the two grades are the reference in Japanese and American grades, there is no significant distinction. Some individuals attempt to explain the mechanical properties distinction. A sample of stainless steel SUS304 gathered from a Japanese source, and an example of stainless steel 304 an American source obtained. Both samples sent for testing in a mechanical lab.

The material SUS304 is a Japanese JIS Standard and one of the most frequently used stainless steels, comprising 18% Cr and 8% Ni. In elevated temperature and low-temperature environments, it can retain excellent strength and heat resistance, and at room temperature, it also has excellent corrosion resistance, weldability, cold workability, and mechanical characteristics.

AISI 304 stainless steel is the material most frequently used in stainless steels and is generally bought in annealed or cold condition. Since SS 304 includes 18% chromium (Cr) and 8% nickel (Ni), stainless steel is also known as 18/8. SS 304 has excellent processability, weldability, resistance to corrosion, heat resistance, low-temperature strength and mechanical characteristics, excellent warm workability such as stamping and bending, and no hardening of heat treatment. SS 304 is commonly used in industrial applications, decoration of furnishings, food, and medical industries, etc.

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SUS304 & SS 304 Chemical Composition

Temperature Range
Steel Grade	SUS304	SS 304
C ≤	0.08	0.07
Si ≤	1.00	0.75
Mn ≤	2.00	2.00
P ≤	0.045	0.045
S ≤	0.030	0.03
Cr	18.00-20.00	17.5-19.5
Ni	8.00-10.50	8.0-10.5

Corrosion Resistance

In a broad spectrum of atmospheric settings and many corrosive media, stainless steel grade 304 is outstanding. In warm chloride environments, it is subject to pitting and crevice corrosion and stresses corrosion cracking above 60 ° C (approximate). Grade 304 is considered to be resistant to drinking water at ambient temperatures up to about 200 mg / L of chloride, reducing it to about 150 mg / L at 60 ° C.

Physical Properties

	Density(g/cm3)	Melting point (℃)	Specific heat (J/kg·℃)	Electrical resistivity (μΩ·m) (20℃)	Thermal expansion (10-6/K)	Thermal conductivity (W/m·K)
SUS304 Material Physical Properties ≤	7.93	1,400-1,450	460-502	0.73	16.3 (20-100℃) 17.8 (20-300℃) 18.4 (20-500℃)	16.8 (100℃)
SS 304 Material Physical Properties	7.93 g/cm3	1398-1454 ℃	500 J/(Kg·K) at 0-100℃	0.73 μΩ·m (20℃)	17.2 (0-100℃) 17.8 (0-300℃ 18.4 (0-500℃)	16.3 (100 ℃)

Welding

Grade 304 has outstanding weldability with and without filler metals through all conventional fusion techniques As 1554.6 pre-qualifies were 304welding with Grade 308 and 304L with 308L tubes or electrodes (and their elevated equivalents in silicon). For peak corrosion resistance, substantial welded segments in grade 304 may involve post-welded annealing. This not need for Grade 304L. If heavy section welding is required and post-weld heat treatment is not feasible, Grade 321 may also used as an option to 304.

In the heated portion, intrinsic corrosion called intergranular corrosion can happen when welding stainless steel, so if weldability is give priority, it has specialized for this intergranular corrosion resistance. You can also choose a grade of stainless steel. Metals have a great picture at elevated temperatures, but when used in a cryogenic environment they may become fragile and crack, but it is known that SUS304 is an outstanding grade of steel for fracture toughness in these settings. A lot of austenitic stainless steel comes from adding and removing different alloy components based on this SUS304, so it's a starting material that can be said to be the mother of other SUS components.

Grade Specification Comparison

Grade	UNS No	Old British		Euronorm		Swedish SS	Japanese JIS
Grade	UNS No	BS	En	No	Name	Swedish SS	Japanese JIS
304	S30400	304S31	58E	1.4301	X5CrNi18-10	2332	SUS 304
304L	S30403	304S11	-	1.4306	X2CrNi19-11	2352	SUS 304L
304H	S30409	304S51	-	1.4948	X6CrNi18-11	-	-

SUS304 VS SS304 Stainless Steel