1.What are the steps in SPCC steelmaking?
After pre-treatment and desulfurization of the blast furnace molten iron, it is sent to the converter for smelting, and then goes through processes such as LF refining to adjust the chemical composition and purity of the molten steel, and then it is cast into slabs through a casting machine.
2.How does hot rolling operate?
The slab is heated to a high temperature, bringing it to an austenitic state, before rolling. This process typically employs a "three highs and one low" process: high-temperature heating, high-temperature starting rolling, high-temperature finishing rolling, and low-temperature coiling. This process aims to dissolve AlN at high temperatures and prevent its precipitation during rapid, low-temperature coiling, preparing for subsequent cold rolling and annealing.
3.How to do pickling?
After hot rolling, iron oxide scale will form on the surface of the steel coil, which is removed through the pickling process to ensure the surface quality and rolling effect of subsequent cold rolling.
4.How does cold rolling work?
The pickled steel coil is rolled through multiple passes at room temperature to reduce its thickness, improve the surface quality and mechanical properties of the steel plate, increase the strength and hardness of the steel plate, and obtain good plasticity and toughness.
5.How does annealing work?
After cold rolling, steel sheets experience work hardening, which reduces their plasticity. Annealing can eliminate this work hardening and residual internal stresses, restoring the steel's microstructure and properties to their pre-cold deformation state. There are two main annealing processes: bell annealing and continuous annealing. Bell annealing involves stacking cold-rolled steel coils and placing them in an annealing furnace for annealing, making it suitable for small-batch, high-variety production. Continuous annealing involves continuously passing the strip through an annealing furnace, offering high production efficiency and suitable for large-batch, low-variety production.