What is the difference between 301 and 304 stainless steel

Although both 301 and 304 stainless steels use iron as a major component, there are several key differences in chemical composition between the two alloys, as shown in the table above, and many compounds in both steel alloys have the same end-capping values. However, grade 304 stainless steel obtained more chromium and nickel than grade 301. This tends to make grade 304 stainless steel more expensive than grade 301.

Most stainless steel alloys have good or excellent corrosion resistance under normal conditions. Stainless steel alloys tend to have a strong, thin oxide layer that prevents rust and are therefore called stainless steel.

There is little difference in corrosion resistance between grade 301 and grade 304 stainless steel under mild corrosion environment at normal ambient temperature. In general, the corrosion resistance of 304 stainless steel in the 301 grade is slightly worse because the 301 alloy has a lower chromium content and a higher carbon content.

At higher temperatures, the difference in corrosion resistance is more significant.

For example, if a piece of 301 stainless steel is to be welded or laser-cut, then signs of corrosion in the heat affected zone are more susceptible to corrosion than a 304 alloy treated in the same way. This is because of chromium carbide precipitation, which depletes chromium in the heat-affected region.

Another key difference between the two types of stainless steel is that the pressure of each stainless steel can be sustained until mechanical failure occurs.

Grade 301 stainless steel with a higher carbon content (0.15% compared to 0.08% by weight of 304) can better withstand mechanical forces. Grade 301 stainless steel may require up to 120 ksi (thousand pounds per square inch) at room temperature.

304 stainless steel can only withstand 90ksi pressure before experiencing mechanical failure. This means that, at room temperature, a basket made of 301 grade stainless steel will experience 33% more stress than a similar basket made of 304 grade alloy.