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The characteristics of 303, 304, 316, 420, 440 Stainless

The characteristics of 303, 304, 316, 420, 440 commonly used stainless steel 303, 304, 316 are all austenitic stainless steel, the main alloying elements are chromium and nickel, most of the time there is no magnetism, slightly magnetic after cold working, mechanical The physical properties are similar, the main difference lies in corrosion resistance and price. 410, 420, 440, and 440C belong to martensitic stainless steel. The main alloying element of this type of stainless steel is chromium, which does not contain nickel. The overall corrosion resistance is not as good as that of austenitic stainless steel, and it is magnetic. Commonly used stainless steel performance comparison said good stainless steel Daquan 304 stainless steel has a chromium content of at least 18% and a nickel content of at least 8%, so it is also called 18/8 stainless steel. This stainless steel has excellent oxidation and corrosion resistance and is the most versatile and common austenitic stainless steel. Compared with 316 stainless steel, 304 is less costly. 303 is based on the addition of sulfur or selenium to 304. The addition of sulfur or selenium improves the machinability. Its composition contains at least 17% chromium, 8% nickel and 0.15% sulfur or selenium. The addition of sulfur slightly reduces corrosion resistance but increases machinability, which is why it is used in fasteners, bushings, bearings and other smaller parts. 316 stainless steel contains at least 16% chromium, 10% nickel and 2% molybdenum. The main difference between 304 and 316 stainless steel is that 316 stainless steel contains molybdenum. The addition of molybdenum improves corrosion resistance, because molybdenum is a transition metal with high corrosion resistance, and it also makes 316 stainless steel have high heat resistance up to 871 °C. If the environment contains a lot of corrosive elements, or for underwater applications, 316 stainless steel is preferred. 410 stainless steel is one of the most commonly used martensitic stainless steels, it contains about 12% Cr and therefore has moderate corrosion resistance. Unlike austenite (such as AISI304 and AISI316), martensite is magnetic and can be hardened by heat treatment such as carbon steel and low alloy steel. 420 stainless steel is basically a high-carbon version of 410, which provides higher strength, has some wear resistance, corrosion resistance and high hardness. This type of stainless steel is used to manufacture parts resistant to atmosphere, water vapor, water and oxidizing acids, such as bearings, instruments, household appliances, guide rails, etc. 440, 440C is high carbon high chromium martensitic stainless steel, 440 has high strength, good hardness, corrosion resistance, wear resistance and high temperature dimensional stability. 440 stainless steel can be quenched and tempered in the same manner as alloy steels. 440C, which is difficult to machine due to its higher annealed hardness and abrasive chromium carbides. 440 and 440C stainless steel are used for bearing parts that work in corrosive environments, and can also be used to manufacture high-quality tools such as medical scalpels, surgical and dental instruments, springs, cutlery, cams, ball bearings, measuring tools, etc. Well, let’s stop here for general stainless steel. So, what exactly is food-grade stainless steel? What is the difference from ordinary stainless steel? What are the common food grade stainless steel? How to distinguish whether stainless steel is food grade stainless steel? How to choose stainless steel tableware and cups? What is the healthiest tableware? What stainless steel is the best cutlery? What should be paid attention to when using stainless steel tableware? How to maintain and clean stainless steel tableware?