Let's start with stainless steel and austenitic stainless steel. The "stainless steel" we usually call and understand is the full name of "stainless acid-resistant steel" - to make the steel not rust, it is actually very simple, just add some metal Impurities can be made into alloy steel (such as adding chromium).
But not rusting, it only means that it will not be corroded by air, and the ability is still too poor. So we also need it to be resistant to chemical corrosion, so "stainless acid-resistant steel" appeared.
If you want to make stainless and acid-resistant steel, you need to add many kinds of metals - to put it bluntly, there is a set of formulas. There are only three common formulations: martensitic stainless steel, ferritic stainless steel and austenitic stainless steel.
Among them, austenitic stainless steel has the best comprehensive performance and no magnetism, so it is the most widely used in our daily life - 304 and 316 belong to austenitic stainless steel.
Let’s talk about the differences between 304 and 316. The stainless steel recipe is the same as our recipe. Controlling the type and amount of different seasonings can change the taste of the dishes. Metal impurities are seasonings; corrosion resistance is the taste.
304 and 316 are two kinds of recipes. The former has been done very well, and its anti-corrosion ability is already very strong. It is positioned as "food-grade" metal by the national standard - normal contact with water, tea, coffee, milk, oil, salt, sauce, vinegar, etc. No problem.
316 stainless steel is a further upgrade on this basis (controlling the proportion of impurities, adding molybdenum) - stronger corrosion resistance. But more capable products tend to cost more—at least in metals, so far. So the price of 316 is also higher.
For food steel, 304 is enough, and there are almost no defects; the use of 316 in this regard is purely overkill, and the aspect that 316 is stronger than 304 is not reflected at all.
As the saying goes, just use the blade, in order to avoid waste, different application environments should choose stainless steel of different materials.