The Differences of Three Kinds of Common Stainless Steel Valves

What's the differences of three kinds of common stainless steel valves?

Stainless steel 201, 304 and 316 are three common stainless steel materials. Although the surface material looks like stainless steel, their uses, prices and characteristics are different. Stainless steel 201 is the most cost-effective stainless steel material with low prices, but it is easy to rust. Stainless steel 304 is the most common and widely used stainless steel material, which is not easy to rust and has good quality and relatively high prices. Stainless steel 316 is an imported material, which is often used in some high-end equipment such as aerospace, food machinery and other fields. Its price is the highest among them. Let's compare the differences between them.

A. What is the differences between stainless steel valves made from 201 and 304?
1. Specifications
Commonly used stainless steel plates are divided into 201 and 304 two kinds. In fact, the composition is different. 304 has better quality, but the price is expensive. 201's quality is worse. 304 is imported stainless steel plate, while 201 is domestic stainless steel plate.
2. Chemical content
Stainless steel 201 is composed of 17Cr-4.5Ni-6Mn-N, which can save Ni and replace 301 steel. It has magnetic properties after cold working and is used for railway vehicles. Stainless steel 304 is composed of 18Cr-9Ni, which is the most widely used stainless steel and heat resistant steel. Stainless steel 304 is used in food production equipment, nuclear energy, etc.
3. Stainless steel 201 has high manganese content, and has features of bright surfaces and easy rust. Stainless steel 304 contains more chromium, and its surface is matte without rust. Put the two together and there's a comparison. The most important thing is that the corrosion resistance is different. The corrosion resistance of stainless steel 201 is very poor, so the price is much cheaper. 201 contains low nickel, so the price is lower than that of 304. Then, the corrosion resistance of 201 is not as good as that of 304.
4. The difference between stainless steel 201 and 304 is the nickel content. The price of 304 is now more expensive, but it can at least guarantee that rust won't happen in the process of use.
5. Stainless steel is not easy to rust because the formation of chromium rich oxide on the surface of the steel body can protect the steel body. 201 belongs to high manganese stainless steel with high hardness, high carbon and low nickel.

B. What is the differences between stainless steel 304 and 316?
1. First of all, stainless steel 316 contains Mo, which has better corrosion resistance than stainless steel 304 in high temperature environment. Therefore, in high temperature environment, engineers generally choose parts made of 316 materials.
2. There are also differences in grades: stainless steel 304 corresponds to Chinese grade 0Cr18Ni9. Stainless steel 316 corresponds to Chinese grade 0Cr17Ni12Mo2.
3. The main reason for stainless steel 316 is to reduce Cr content, increase Ni content and increase Mo 2% to 3%. As a result, its corrosion resistance is stronger than 304, which is suitable for useing in chemical industry, seawater and other environments. Similarly, the cost of stainless steel 316 is higher than that of 304. Generally, 316 is used in places with higher requirements instead of 304.

However, the naked eye can not see the difference between 304 and 316 stainless steel. There is a more intuitive identification method, using stainless steel liquid for identification. That is the use of stainless steel liquid medicine.