Are you struggling between 18-8 stainless steel and 18-10 stainless steel? Here is the Solution. You should know which steel grade is best for your working environment. As you know, choosing the wrong grade might create a problem in the future. We will discuss the main difference in chemical, mechanical, and physical and many more in this article.
General properties
18-8 meet various physical requirements and can be excellent for different applications like storage tanks, pressure vessels, and piping, truck bodies, clamps, kitchen equipment, hose clamps, springs, etc.
Whereas 18-10 ate durable, easy to clean, weld, fabricate, and finish. It has excellent resistance to the chemical environment than 18-8. 18-8 is also known as A2 stainless or 304 Stainless steel whereas 18-10 is known as A4 Stainless or 316 Stainless steel
Chemical composition
18-8 contains 0.07 % carbon, 2% manganese, 1% Silicon, 0.045% phosphorous, 0.015% sulphur, 17.5-19.5 % chromium, and 8.0-10.5% nickel where as 18-10 stainless steel contains 0.07 % carbon, 2% manganese, 1% Silicon, 0.015% sulphur, 16.5-18.5 % chromium,0.045% phosphorous, 10.0-13.0% nickel and 2.0-2.5% molybdenum the main difference in the chemical composition b/w 18-8 and 18-10 is chromium, nickel and molybdenum composition in which 18-10 is a good choice for marine environment as compare to 18-8
Resistance to corrosion
In 18-8 stainless steel 8% nickel, 18 % chromium provides good corrosion resistance to moderately acidic environments, whereas 18-10 stainless steel has the addition of 2% molybdenum, which makes 18-10 SS more corrosion and oxidation resistance in corrosive environments. So if you need more protection against a highly corrosive environment, than 18-10 will be a good option; also its is more costly than 18-8 SS. We should properly analyze the working environment, and based on your budget, the proper grade should be selected.
Mechanical and physical properties
| Grade | 18-8 | 18-10 |
| Density (kg/m3) | 8000 | 8000 |
| Elastic Modulus (GPa) | 193 | 193 |
| Mean Coefficient of Thermal Expansion (μm/m/°C) | 17.2 / 17.8 / 18.4 | 15.9/16.2/17.5 |
| Thermal Conductivity(W/m.K) | 16.2 / 21.5 | 16.3/21.5 |
| Specific Heat 0-100°C (J/kg.K) | 500 | 500 |
| Electrical Resistivity (n.m) | 720 | 740 |
| Tensile Strength (MPa) min | 515 | 515 |
| Yield Strength 0.2% Proof (MPa) min | 205 | 205 |
| Elongation (% in 50mm) min | 40 | 40 |
| Rockwell B (HR B) max | 92 | 95 |
| Brinell (HB) max | 201 | 217 |
Cost
The costs for stainless steel depend primarily on the composition of the alloys. Alloys that are present in the steel provides the difference in their mechanical and physical properties and also the cost of the grade which is going to be produced. 18-8 steel does not contain an additional 2 % molybdenum Whereas 18-10 steel contains additional 2% molybdenum, which makes it more costlier than 18-18.
Magnetism
SS 18-8 and 18-10 are austenitic, and they have no magnetic properties, although cold working may have an effect on this. If the stainless steel is formed or cut, the magnetic properties can increase slightly, although they are still small.
Application
| 18-8 | 18-10 |
| Commercial food processing equipment | Refinery equipment |
| Fasteners | Medical devices |
| Piping | Marine environments, especially those with chlorides present |
| refrigerators and dishwashers | Chemical processing and storage equipment. |
Summary
So we have discussed various differences b/w 18-8 and 18-10. You should decide based on the working environments in which grade will be best for your application. You can use 18-10 in a more corrosive environment like marine application, extremely high corrosive, and oxidative environment since it contains an additional 2% molybdenum. Its cost is slightly high than 18-8 SS, so you should do a better analysis of the working environment. 18-8 is less costly than 18-10 since it does not contain an additional 2 % molybdenum. It is best for kitchen applications, piping, refrigerators, etc. It has good performance in a sightly low corrosive environment and also budget-friendly. Jayveer Steel is a manufacturer and exporter of all types of steel, including 18-8 and 18-10 Steel. We are exporting the best quality of steel for more than 20 years. All material is provided in various shapes, sizes, and colors.