What is the difference between 300 and 400 series of stainless steel?

300 and 400 series stainless steel price difference

the price difference between both stainless steel series is on account of the inclusion of elements in their chemical composition. the chemistry of 300 series steels includes chromium, nickel, and molybdenum as their base elements. on the other hand, the 400 series includes elements such as chromium and manganese. the absence of nickel in their chemistry is what makes all stainless steel alloys under the 400 series cost less, in comparison to 300 series. and as nickel is a commodity metal, its price remains volatile. fluctuating prices almost always lead up to an upcharge in the cost of using nickel as an element in the alloy. this in turn affects the overall costing of the products.

300 and 400 series corrosion resistance levels

since both series have several alloy grades that fall under them, their resistance to corrosion will depend on their chemical composition. however, if we were to compare both the series as a whole, the austenitic class 300 series stainless steel would outperform the martensitic class series 400. this is for several reasons. first, the use of nickel and chromium is high in the 300 series, which means the resistance of the alloy to corrosion also becomes higher. as the alloying is relatively lower in the grade 400 series, the resistance to corrosion is lower, which means these steel alloys are easily corroded by rust. aside from nickel, the 400 series has trace additions of manganese, sulfur, phosphorus, etc. which while helpful, do not play a major role in enhancing the corrosion resistance properties of said alloys. yet, the higher content of carbon increases its wear resistance properties.

300 vs 400 series tensile and yield strength

since the 300 series belongs to the austenite variety, they are highly ductile, and so they can be easily deformed. on the other hand, the martensitic structure, with a higher content of carbon makes the 400 series much stronger because they tend to have a higher hardness. an increase in the content of carbon is also what makes the 400 series stainless steels stronger.

300 and 400 series stainless steel weldability

weldability is affected by the content of carbon in the alloy. the higher the weldability, the lower the quality of the weld and the more the alloy becomes susceptible to intergranular corrosion. although both series are weldable by conventional techniques, modifications made with regards to the carbon content permits their weldability.