Thermos Cup industry will often involve 201 stainless steel, 304 stainless steel and other professional terms, then what is 201, 304 stainless steel?

We must first know what is stainless steel, the so-called stainless steel refers to the resistance to air, steam, water and other weak corrosive medium and acid, alkali, salt and other corrosive corrosion of the medium of steel, is by adding nickel, molybdenum, titanium, niobium, copper, nitrogen and other elements of the alloy.

304 stainless steel is a versatile stainless steel material, anti-rust performance than 200 series of stainless steel material to be strong. High temperature resistance is also relatively good, can be up to 1000-1200 degrees. 304 stainless steel has excellent corrosion resistance and good intergranular corrosion resistance. For oxidizing acids, it is found in the experiment that the 304 stainless steel has a strong corrosion resistance in the nitric acid under the boiling temperature of the concentration ≤65%. Alkali solution and most organic acids and inorganic acids also have good corrosion resistance.

According to the composition can be divided into CR System (400 series), NI Department (300 series), Cr-mn-ni (200 series) and precipitation hardening System (600 series). 200 Series-chromium-nickel-manganese austenitic stainless Steel 300 series-chromium-nickel austenitic stainless steel 301-ductility is good for molding products. It can also be hardened quickly by machining. Good weldability. Abrasion resistance and fatigue strength are better than 304 stainless steel. 302-corrosion resistance with 304, because the carbon content is relatively high and thus better strength. 303-By adding a small amount of sulphur and phosphorus makes it easier to cut and process than 304. 304-18/8 Stainless steel. GB brand is 0cr18ni9.

International Stainless Steel Marking method

The American Iron and Steel Society uses three digits to mark a variety of standard grade wrought stainless steels. One：

① austenitic stainless steel is marked with a number of 200 and 300 series.

② ferrite and martensitic stainless steel are represented in the 400 series. For example, some of the more common austenitic stainless steels are marked with 201, 304, 316, and 310.

③ ferritic stainless steel is marked with 430 and 446, and martensitic stainless steel is labeled as 410, 420 and 440C, and dual-phase (austenitic-ferrite).

④ stainless steel, precipitated hardened stainless steel and high alloy with iron content below 50% are usually named after a patent or trademark.

4). Classification and grading of standards

Tensile strength Σb (MPa) ≥520, conditional yield intensity σ0.2 (MPa) ≥205, elongation rate δ5 (%) ≥40, section shrinkage rate of psi (%) ≥60, hardness: ≤187HB; ≤90hrb; ≤200hv

We understand the stainless steel these parameters, we should probably have some understanding of the main materials of these cups, poor corrosion resistance of stainless steel materials, acid and alkali, and so weak. Concise, is the main material has good or bad points. The reason is very simple, good insulation must be made of good stainless materials, and good steel is bound to increase costs. Take many small factories for example, they have no brand, no innovation, no scale, no market, then how to drink in the competitive cup pot market, only jerry-building, shoddy. So many small factories abuse 201 of inferior steel, and even some pusher with stainless iron insulation. If not a professional, only from the appearance is difficult to judge the material of a thermos flask, which makes the unscrupulous manufacturers have place, ultimately infringing consumers.