Why is 316 stainless steel more expensive than 304?
Stainless acid-resisting steel is what we usually call stainless steel -- to keep steel from rusting, it is very simple to make alloy steel by adding some metal impurities (such as adding chromium).
However, not rust, only means that it will not be corroded by the air, and the performance is still poor. We also need it to resist chemical corrosion, so there is "stainless acid-resisting steel ".
To make stainless steel, you need to add many kinds of metals -- basically, there is a formula. There are only three common formulas: martensitic stainless steel, ferritic stainless steel, and austenitic stainless steel. Among them, austenitic stainless steel has the best comprehensive performance and no magnetic, so it is the most widely used one in our daily life - 304 and 316 are austenitic stainless steel.
When we talk about the differences between 304 and 316 stainless steel, its formula is just like our recipe. We can change the taste of our dishes by controlling the type and amount of condiments. Metal impurities are the condiments while corrosion resistance is taste.
304 and 316 are two recipes. The former has done very well with strong corrosion resistance and is certified as the "food grade" metal by the national standard, which means, it can contact water, tea, coffee, milk, oil and salt sauce vinegar, and so on.
316 stainless steel is a further upgrade on this basis with stronger corrosion resistance (control the proportion of impurities, adding molybdenum). But high-performance products tend to cost more -- at least in metals, so far, so the price of 316 is also higher.
For food steel, 304 is sufficient, and there are almost no defects. The use of 316 in this regard is purely overqualified, and the aspect that 316 is better than 304 does not show at all. To avoid waste, different applications should choose different types of stainless steel.