The electric arc furnaces are the most widely used steel furnace around the world, they can be used to smelt high-quality steel and other special steel. Though the arc furnace came out in the 1900s, the major development waited its time till the end of WWII. During the latest decades, the development has escalated and brought revolutionary changes to the steel industry.
While the total output capacity remains growing slowly, the percentage of crude steel made from scraps has rising fiercely to 40% in 2001. One of the major solutions, arc furnace can be built and operated at a lower cost than the traditional blast furnace. Since the concept of the UHP arc furnace(ultrahigh power arc furnace) emerged in the mid-60s, people have tried to build a bigger furnace with higher power and capacity. The application of advanced technologies like dynamic compensation systems and water-cooling systems boosts the development vigorously.
There are several essential elements that caused the evolution:
- The increasing quantity of scrap steel;
- The rapid development of the entire steel industry. The supply and the price of electricity become stable, which makes it possible to generalize the arc furnace;
- The arc furnace tends to be larger and more powerful;
- Less investment, quick to construct, and fast cost recovery;
- The temperature and the component of the molten steel can be controlled with accuracy. The arc furnace can also smelt various kinds of different steel.
Compared with others, the electric arc furnace also has several obvious advantages:
- The arc can heat the furnace and the steel up to 4000-6000℃directly and smelt special steels that contain refractory elements like W and Mo.
- The arc furnace could remove the toxic gases and the inclusions while deoxidizing and desulfurating.
- High flexibility. The arc furnace is capable of engaging production continuously or intermittently.
Currently, owing to the development of related technologies, electric arc furnaces could be well-integrated with traditional steel-making processes. But there are also several deficiencies that need to improve:
- The arc can only generate point-like heating sources, which will cause uneven heat distribution in the furnace.
- The arc will react with the furnace gases and vapor and release large quantities of H2and N2.
