18/8 stainless steel VS 304

What is 18/8 stainless steel?

18/8 stainless steel, also known as 304 stainless steel, contains 18% chromium and 8% nickel. It is known for its excellent corrosion and heat resistance, making it suitable for applications such as kitchenware and medical equipment. It exhibits good workability at room temperature (such as deep drawing and bending) and does not harden after heat treatment. While resistant to most food processing media and organic compounds, it may corrode in concentrated acid and chloride environments at high temperatures.

 

What is 304 Stainless Steel?
304 stainless steel is the most common austenitic stainless steel, with typical composition:Chromium: 18–20%,Nickel: 8–10.5%,Carbon: ≤0.08%,It's essentially a specific type of 18-8 stainless steel, standardized by ASTM and other bodies (e.g., AISI 304, EN 1.4301). This makes 304 a more precise material designation compared to the broader 18-8 term.

 

 

Is 18-8 stainless steel the same as 304?
Answer: Not exactly. 304 stainless steel is one specific grade within the 18-8 family. All 304 is 18-8, but not all 18-8 is 304. The 18-8 term can also include grades like 302 or 305.

 

304 Stainless Steel Chemical Composition 

Grade	C	Mn	P	S	Si	Cr	Ni	N
304	≤0.08	≤2.00	0.045	0.030	0.75	18-20	8.0-11	≤0.10
304L	≤0.03	≤2.00	0.045	0.030	0.75	18.0-20.0	8.0-12	≤0.10
304H	0.04-0.10	≤2.00	0.045	0.030	0.75	18-20	8.0-10.5	–
304N	≤0.08	≤2.00	0.045	0.030	0.75	18-20	8.0-10.5	0.10-0.16

Which is more corrosion-resistant, 18-8 or 304?

If we compare generic 18-8 with standardized 304, both have similar corrosion resistance in mild environments. However, 304 offers more predictable performance due to tighter composition limits and certified properties.

 

304 Stainless Steel Mechanical properties

Grade	Yield Point	Tensile Strength	Elongation	Hardness	Hardness
	MPa	MPa	%	HRB	HB
304	≥ 205	≥ 515	≥ 40	≤ 92HRB	≤ 201
304L	≥ 170	≥ 485	≥ 40	≤ 92HRB	≤ 201
304H	≥ 205	≥ 515	≥ 40	≤ 92HRB	≤ 201
304N	≥ 240	≥ 550	≥ 30	≤ 95HRB	≤ 217

 

Can 18-8 stainless steel rust?

Yes,both 18-8 and 304 can rust in harsh chloride environments (e.g., seawater, salted roads). For higher resistance, consider 316 stainless steel with molybdenum.

 

Is 18-8 stainless steel food-safe?

Yes,most 18-8 stainless steels, including 304, are widely used in food contact applications due to their non-reactive nature and compliance with FDA food-grade standards.

 

Which should I buy: 18-8 or 304?

If your project requires documented mechanical and chemical properties for certification, choose 304. For general hardware like bolts and fasteners where formal certification isn't required, 18-8 may be sufficient.