Hot Rolling Mill och Cold Rolling Mill

The hot rolling process, like the rebirth of steel, heats the billet to a recrystallization temperature (usually above 1100℃C), at which point the atoms inside the metal gain enough kinetic energy to make the lattice structure soft and plastic. Under the strong pressure of the four-high reversing mill, the red-hot billet stretches and deforms like dough, and the rolling force can reach tens of thousands of Kor . Denna hög temperaturmiljö gör det möjligt för metallen att upprätthålla dynamisk omkristallisationskapacitet, och arbetshärdningen som genereras av varje rullande process kan omedelbart elimineras .
The cold rolling process is the frost quenching of metal, and the hot rolled coil is rolled at room temperature after pickling. The metal atoms are frozen in a fixed lattice, and the rolling process causes dislocation proliferation and grain elongation. The precision roll system of the six-high UC mill applies rolling pressure up to 2000MPa, so that the strip thickness accuracy is kontrolleras inom ± 1μm . Arbetets härdningseffekt fortsätter att ackumuleras, vilket tvingar materialets utbytesstyrka att öka med 30%-50%.
The temperature difference creates a very different microscopic world: the equiaaxial grain diameter of hot-rolled steel is about 50μm, and the fibrous grain of cold-rolled steel is only 10μm. This difference in microstructure directly leads to the differentiation of mechanical properties, and the elongation of hot-rolled products can reach 25%, while the hardness of cold-rolled materials can be increased to more than Hv 200.