Stainless steel is a widely used metal material, which can be divided into two categories according to its characteristics and uses. One is stainless steel with stainless steel, which shows excellent corrosion resistance in weakly corrosive media such as air, water steam and water; The other is acid-resistant steel, which can resist the corrosion of chemical media such as acid, alkali, salt, and will not be corroded itself. Stainless steel is a kind of metal material that we often come into contact with in our daily life.

In our daily life, there are many items made of stainless steel, such as household kitchenware and tableware, as well as food containers and food processing equipment. These products made of stainless steel are called stainless steel products for food contact. In all stainless steel products for food contact, kitchen utensils account for 80% of the proportion. However, if poor quality stainless steel products are used as kitchenware or tableware, the heavy metal components in them are easier to precipitate in high temperature or acid and alkali environments, resulting in greater risks.

Probably most people think that stainless steel refers to the kitchen utensils and tableware used in our daily life, this understanding is actually one-sided. In fact, the word "stainless steel" does not just refer to one kind of stainless steel, but covers more than one hundred different industrial stainless steels. In different fields and applications, different types of stainless steel are used.

The main types of stainless steel include martensitic steel, ferritic steel, austenitic steel, chromium stainless steel, chromium nickel stainless steel, chromium manganese nitrogen stainless steel, etc. From 2010 to 2019, the global supply of stainless steel remained generally stable. In this decade, the global production of stainless steel increased from 31.094 million tons to 52.218 million tons, with a compound annual growth rate of 5.93%, of which China's supply increase is the largest. However, there have been many major changes in the global economic situation in 2020, and the global epidemic has caused many uncertainties, resulting in weak global economic growth, which has caused a decline in global stainless steel production. Global stainless steel production in 2020 totaled 50.89 million tons, down 2.5% year-on-year. By 2022, the global production of stainless steel crude steel is 55.255 million tons, down 5.2% year-on-year.

Asia is the world's main concentration of stainless steel production. In 2022, the world's major stainless steel production has declined, but China is still the world's largest stainless steel producer. Europe's stainless steel production was 6.294 million tons, down 12.4% year on year; Production in the United States was 20.17 million tons, down 14.8 percent. China's stainless steel production was 31.975 million tons, down 2.0% year-on-year, accounting for 57.9% of global production; Stainless steel production in Asia (excluding China and South Korea) was 7.411 million tons, down 4.9% year-on-year; Stainless steel production in other countries (Brazil, Russia, South Africa, South Korea, Indonesia) was 7.557 million tons, down 9.1% year-on-year.

The main application areas of stainless steel products worldwide are metal products and mechanical engineering. According to the global stainless steel consumption forecast released by the World Stainless Steel Association during the World Stainless Steel Conference, it is expected that by 2022 and 2023, global stainless steel consumption will decline by 0.6% and increase by 3.2%, respectively, and social demand is generally stable. In 2020, the main global consumption areas of stainless steel are metal products and mechanical engineering, which account for 37.7% and 28.7% of consumption, respectively.

With the gradual fading of the impact of the global epidemic and the further recovery of social demand, global stainless steel consumption is expected to further increase. In general, the global trend of stainless steel consumption is stable, benefiting from the application of new high-end stainless steel varieties and the further improvement of energy-saving production processes, the future global stainless steel consumption is still likely to maintain steady growth.

The element content of stainless steel products mainly includes nickel (Ni), chromium (Cr), molybdenum (Mo), iron (Fe) and so on. Whether it is domestic or imported stainless steel products, they need to go through strict testing and certification before entering the market.

There are many testing items for stainless steel products, including bending, repeated bending test, high temperature, room temperature, low temperature tensile test, Rockwell hardness test, Brinell hardness test, Vickers hardness test, room temperature impact test, low temperature impact test, high temperature impact test, multiple impact test, etc. In addition, there are heavy metal detection, RoHS detection; Compression test: compression yield point, compressive strength, non-proportional compression stress, total compression stress, compressive elastic modulus; Physical properties: magnetic properties, electrical properties, thermal properties, oxidation resistance, wear resistance, salt spray, corrosion, density, coefficient of thermal expansion, hardness; Corrosion performance: atmospheric corrosion, intergranular corrosion, stress corrosion, pitting corrosion, corrosion fatigue, artificial atmosphere corrosion; Coating related tests (thickness, quality, adhesion, etc.); Mechanical properties: tensile, bending, yield, fatigue, torsion, stress, stress relaxation, impact, wear, hardness, hydraulic resistance, tensile creep, flaring, flattening, compression, shear strength, etc. Process properties: filament drawing, fracture inspection, repeated bending, bidirectional torsion, hydraulic test, flaring, bending, crimping, flattening, ring expansion, ring stretching, microstructure, metallographic analysis; Formability test: (lug rate, protruding, coning, reaming, deep drawing, forming limit diagram FLD), flow stress compression test, thermal simulation test