Which 304 stainless steel is more corrosion-resistant, cold rolling or hot rolling?

304 stainless steel is a common stainless steel material with good corrosion resistance. It is often used in the manufacturing of chemical equipment, 식품 가공 장비, medical equipment, building decoration and other fields. There are two production methods of stainless steel: cold rolling and hot rolling. Different production methods will affect the corrosion resistance of stainless steel. So, which one of cold-rolled or hot-rolled 304 stainless steel is more corrosion-resistant?

First of all, cold rolling and hot rolling are two different processing methods in the stainless steel production process. Cold rolling refers to a process in which stainless steel slabs are pressed and stretched at room temperature through multiple passes to make them thinner and enhance their hardness and strength. Hot rolling refers to the process of heating the stainless steel slab to a certain temperature and deforming it through mechanical force.

For 304 stainless steel, it can obtain good corrosion resistance in both cold rolling and hot rolling. However, since the structure and properties of stainless steel are jointly determined by factors such as grain size, grain shape, and phase composition, cold rolling and hot rolling will have different effects on the grain size and shape of 304 stainless steel.

During hot rolling, due to the rapid formation and growth rate of metal grains in the steel billet under high temperature, the grains appear large and coarse. During cold rolling, the steel plate is stretched and squeezed, and the grain size becomes smaller and the deformation increases, thereby forming more corrosion-resistant dislocations on the grain boundaries and improving the corrosion resistance of stainless steel.

In addition, cold rolling can also make the surface finish of stainless steel plates higher, which is beneficial to improving its corrosion resistance. Moreover, the surface of cold-rolled 304 stainless steel plates has no scale and rust spots and is not easily eroded by corrosive media, so it has better corrosion resistance.

At the same time, cold rolling and hot rolling also have an impact on the mechanical properties and surface quality of stainless steel. There will be irregular oxide scale on the surface of hot-rolled stainless steel plates, while the surface of cold-rolled stainless steel plates is relatively smooth. However, cold-rolling processing will make the stainless steel plates hard, which will increase the difficulty of processing and increase the cost.

Generally speaking, for 304 stainless steel, cold-rolled plates are more corrosion-resistant. However, in specific applications, choices need to be made according to different situations. If you need a higher surface finish, you can choose hot-rolled stainless steel plates; if you need higher strength and hardness, you can choose cold-rolled stainless steel plates.

In addition, the corrosion resistance of stainless steel plates is also related to surface treatment. For example, surface treatments such as pickling and polishing can further improve the corrosion resistance of stainless steel plates.

In short, when selecting stainless steel plates, it is necessary to comprehensively consider the characteristics of the material and the specific application requirements to select the most appropriate material.