What problems should be paid attention to when rolling stainless steel slab into hot rolling

At present, the production of stainless steel plates is basically cast by continuous casting machines. The thickness of the slab is about 140-200mm, and the width is about 900-1600mm. According to the use of the stainless steel plate to be produced, the slab can be cut Into the length ranging from 5-12m.

During the manufacture of slabs, casting mold slag is usually added to the surface of molten steel, which not only cuts off the contact between the surface and the atmosphere, but also forms a molten slag film between the mold and the continuously solidified steel shell. It acts as a lubricant.
The surface quality of the slab will have a great impact on the surface quality and pass rate of the subsequent process, and optimizing the corresponding casting conditions can improve the surface quality of the slab.
The stainless steel plate rolled from the slab needs to be hot-rolled. Regarding the heating temperature, the austenitic stainless steel is about 1250 ℃, and the ferritic stainless steel is about 1180 ℃. Stainless steel tends to be softer and less work hardened when heated at high temperatures. However, the thermal deformation resistance of stainless steel is more than twice that of carbon steel, and rolling is more difficult. Among them, the deformation resistance of stainless steel containing high nickel and nitrogen is higher, so rolling is more difficult.
Therefore, from the perspective of convenient rolling, the higher the heating temperature, the better, but excessive surface oxidation caused by high temperature will lead to the generation of various surface defects. So the heating temperature should not be too high. Generally speaking, during hot rolling, it is very important how to end rolling without the temperature dropping.
Common hot rolling mills are divided into two types: tandem rolling mill and reversing steckel rolling mill. The tandem mill is a way to do rapid rolling without temperature drop. The reversible steckel rolling mill is a finishing mill equipped with a holding furnace and a coiler. It is a rolling mill that can not only keep warm but also roll at the same time.
During hot rolling, the stainless steel strip moves at high speed after it comes out of the furnace, so how to make stainless steel move stably at high speed is a key aspect of hot rolling technology.
Hot rolling is divided into rough rolling and finish rolling. The rough rolling mill is the equipment for rolling the thickness of the slab to about 25mm, and the finish rolling mill is the equipment for rolling the rough-rolled billet to about 2-9mm stainless steel coil.
During heating, scales will be formed on the surface of stainless steel slabs, and the generation of scales can be controlled by controlling the atmosphere and flame in the heating furnace, and the scales can also be washed with high-pressure water before rough rolling, but this cannot be completely remove. In addition, no matter which rolling mill is used, the rolls will wear as rolling progresses. If the wear is uneven, sometimes patterns will appear on the surface of the roll, so the wear and surface management of the roll is also the focus of the hot rolling process.