304 food grade stainless steel

304 stainless steel is the most common type of food-grade stainless steel. It is an austenitic stainless steel with excellent corrosion resistance and can resist chemical oxidation. This material is very common in food contact situations, such as stainless steel pressure cookers and food industry pipelines. Due to its excellent performance, 304 stainless steel is a material that meets national food standards and can be used safely in food contact situations.

Application areas ‌

Due to its good corrosion resistance, formability and high toughness, 304 stainless steel is widely used in various fields. For example, food production equipment, chemical equipment, medical equipment, architectural decoration, automotive accessories, etc. Especially in the food industry, 304 stainless steel is widely used in the production of tableware, kitchen utensils and other products that come into direct contact with food due to its non-toxic and harmless characteristics.

304 Stainless Steel Product Standards

The product standards of 304 stainless steel mainly include its chemical composition, physical properties and application areas. ‌‌

Chemical composition: The main components of 304 stainless steel include chromium (Cr) and nickel (Ni). Specifically, 304 stainless steel contains 18%-20% chromium and 8%-10% nickel. This composition gives 304 stainless steel excellent corrosion resistance and high toughness. In addition, the chemical composition of 304 stainless steel also involves the content control of elements such as carbon (C), silicon (Si), manganese (Mn), phosphorus (P), and sulfur (S) to ensure its performance.

‌Physical properties: The density of 304 stainless steel is 7.93 g/cm³ and it has weak magnetism. After cold working, its magnetism will be enhanced. In addition, the tensile strength of 304 stainless steel is 520MPa, the hardness is about 187HB, 90HRB, 200HV, the linear expansion coefficient is 17.2-18.4 in the range of 0-100K, the melting point is about 1398℃-1454℃, the specific heat capacity is 0.50kJ/(kg·K), the thermal conductivity is 16.3W/(m·K) at 100℃, 21.5W/(m·K) at 500℃, the resistivity is 0.73×10⁻⁶Ω·m, and the longitudinal elastic modulus is 193kN/mm.

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304 stainless steel identification method

1. Check the mark: You can check whether the product has the SUS304 mark, or check the material content and test report in the product manual. If it is stated that the material is food grade 304, if not, it is usually made of stainless iron or other materials.

2. Detection with reagents: Reagents for detecting metal materials are very common in the market. Just drop the reagent on the product and let it stand for 3S. If the color is malachite green, it is the real 304 material.

3. Salt spray test: 304 stainless steel has the characteristics of corrosion resistance, acid and alkali resistance. The product can be verified according to the operating steps of the salt spray test. The salt spray test is a process of accelerating rusting. If it rusts quickly, it is not the real 304. Generally, 304 can be tested for 48 hours without rusting in the salt spray test.