201 J1/J2/J3/J4/J5 Cold Rolled Stainless Steel Coil

Type 201 stainless steel is a low nickel, high work hardening, austenitic chromium-nickel-manganese stainless steel. Type 201 stainless steel is not hardenable by heat treatment. In some cases, it can replace other alloys with higher nickel content.

Stainless steel is made by extracting chromite ore from underground mines. Chromite ore is crushed to produce chromite concentrate. Chromite concentrate is melted in electric furnaces along with other raw materials (iron ore, manganese, nickel, etc.) for specific stainless steel types.

The chemical composition of 201 and 304 stainless steel is quite different. The carbon content of 201 stainless steel is 0.15%, which is 0.08% higher than that of 304 stainless steel, and the carbon content is nearly doubled. Therefore, the specified non-proportional extension strength Rp0.2 of 201 stainless steel is larger than that of 304 (201: 275N/mm2, 304: 205N/mm2).

The Cr element of 201 and 304 stainless steel is not much different. The Cr content of 201 stainless steel is 16.00~18.00%, and the Cr content of 304 stainless steel is 18.00~20.00%.

However, the Ni element content of 201 stainless steel is much smaller than that of 304 stainless steel. The Ni element content of 201 stainless steel is 1.50~5.50%, while the Ni element content of 304 stainless steel is 8.00~11.00%. The Ni element content of 304 stainless steel is twice that of 201 stainless steel. above.

The corrosion resistance of stainless steel depends on chromium (Cr). When the amount of chromium added reaches 10.5%, the atmospheric corrosion resistance of steel increases significantly, but when the chromium content is higher, although the corrosion resistance can still be improved, it does not Obviously, therefore, the national standard GB/T 20878-2007 defines stainless steel as: stainless steel with stainless and corrosion resistance as the main characteristics, and the chromium content is at least 10.5%, and the carbon content does not exceed 1.2%.

The main reason why stainless steel does not rust is that it contains more than 10.5% chromium. The presence of this element allows the stainless steel to form a passivation film on the surface when it undergoes an oxidation reaction, which plays the role of isolating the air and cannot be touched by steel or iron. Oxygen, naturally there will be no reaction and rust.

Stainless steel is not always rust-free. External storage environment factors are very important. It will not rust under dry and well-ventilated conditions. If it is continuous rainy weather or the ph in the air is high It is easy to rust, and it is easy to rust after staying in a humid and dark environment for a long time.

Whether stainless steel will rust or not is a more important factor to look at the nickel (Ni) content inside. Nickel can expand the passivation range and improve corrosion resistance, especially in non-oxidizing media (such as dilute sulfuric acid).