The Advantages And Disadvantages Of Electric Arc Furnace

The Advantages And Disadvantages Of Electric Arc Furnace

There are several essential elements that caused the evolution of the electric arc furnace:

1) The increasing quantity of scrap steel;

2) 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;

3) The arc furnace tends to be larger and more powerful;

4) Less investment, quick to construct, and fast cost recovery;

5) The temperature and the component of the molten steel can be controlled with accuracy. The arc furnace can also smelt various kinds of different steels.

Compared with others, the electric arc furnace also has several obvious advantages:

1) The arc furnace can heat the furnace and the steel up to 4000-6000℃ directly and smelt special steels that contain refractory elements like W and Mo.

2) The arc furnace could remove the toxic gases and the inclusions while deoxidizing and desulfurating.

3) High flexibility. The arc furnace is capable of engaging production continuously or intermittently.

Currently, owing to the development of related technologies, the electric arc furnace could be well-integrated with traditional steel-making processes. But there are also several deficiencies that need to be improved:

(1) The arc can only generate point-like heating sources, which will cause uneven heat distribution in the furnace.

(2) The arc will react with the furnace gases and vapor and release large quantities of H2 and N2.

With further improvement of the electric arc furnace, new smelting techniques will embrace a brighter prospect.

The Advantages Of Induction Furnace

The Advantages Of Induction Furnace

According to Wikipedia, the induction furnace is an electrical furnace in which the heat is applied by induction heating of metal. Induction furnace capacities range from less than one kilogram to one hundred tons capacity and are used to melt iron and steel copper, aluminum, and precious metals.

Heating fast, high temperature, easy operation and control, and the less pollution

It is an electric furnace for heating a material using an induced current generated by an induction coil. The material will be placed in a crucible made of refractory material if the metal material is heated. If the non-metallic material is heated, the material is placed in a graphite crucible. Furthermore, the induced current frequency will be corresponding to the increase and result in increased heat when the AC frequency is increased. Induction furnace heating fast, high temperature, easy operation and control, and less pollution of material in the heating process to ensure a high-quality product.

Clean, Energy-efficient

The advantage of the induction furnace is a clean, energy-efficient and well-controllable melting process compared to most other means of metal smelting. Most modern foundries use this type of furnace, and now also more iron foundries are replacing cupolas with induction furnaces to melt cast iron, as the former emit lots of dust and other pollutants.

Uniform heating, small table temperature difference, high accuracy of temperature control

The reason why the uniform heating and the small core table temperature difference is simply because of heat generated in the workpiece itself. And the application of the temperature control system can achieve precise control of the temperature to improve product quality and pass rate.

In addition, the medium frequency induction furnace heating device has the advantages of small volume, light weight, high efficiency, excellent quality of hot processing, and environment-friendly. It rapidly replaces the coal-fired stove, gas stove, fuel stove, and ordinary resistance furnace, which is a new generation of metal heating equipment.

Stainless Steels

Stainless Steels

Stainless steels are selected in accordance with their corrosion resistance. They have been used for almost more than 100 years cause of their durability, appearance, and cleanability. These things can be found in your home, prestigious buildings, transport, food, and beverage handling, chemical plant, and medical equipment.

Chromium is one of the essential elements of stainless steel, which makes it has stainless characteristics, but most commonly the used grade is type 304, containing 8% nickel. Furthermore, it is one of a family of grades known as “austenitic”. They are featured with good ductility as well as ease of forming and welding. Because it is maintained at very low temperatures, so they can be selected for cryogenic applications. While some grades retain their properties to high temperatures as well. 

Nickel is an important alloying element in all the commercial grades of the duplex stainless steel family. These have higher strength than the common austenitic grades but cannot be used over such a wide temperature range. Nevertheless, they are finding increasing use in structural applications where strength is important.

Some grades within the other families of stainless steels - ferritic, martensitic, and precipitation hardening - do contain a small percentage of nickel which enhances their properties.

Stainless steel is the largest single first use of nickel, accounting for 60.9% of nickel production in 2009. In the same period, 58.3% of the stainless steel was melted with chromium-nickel austenitic grades.

The Device Of the Electric Arc Furnace

The Device Of the Electric Arc Furnace

Electric Arc Furnace

An electric arc furnace consists of a shell, spout, cover(optional), furnace wall, bottom electrode device, and tilting system.

The furnace shell is water cooling style, the furnace side has a spout, the furnace inside wall has refractory, water cooling electrode style, temperature testing, and the spout was made by refractory.

Electrode Lifting Device

Electrode lifting device includes a conductive arm, lifting pole column, guiding column, electrode clamp, and lifting reduction box device.

Electrode clamps of conductive arms use non-magnetic conductive stainless steel, high mechanic, high wear resistance, deep hole, water cooling inside and cooling directly, and enhance the cooling effect, prolong the operational life span.

Large Current

Large current includes DC power supply compensator, copper bar, furnace body electrode connector, eliminator supply cable connector, big section cable, conductive arm, electrode clamp, and graphite electrode.

Water Cooling

The water cooling system is composed of the current switch, water distributor, return line, water cooling pressure less than 2XlO5Pa, and water cooling temperature below 32℃, this device has flow warning, it alarms when the flow is below the related value.

The Application Of Flying Shear

The Application Of Flying Shear

The Flying Shear is a common industrial application in rolling mill production lines for cutting a product into smaller lengths, without stopping the line, this means that the main production process is not interrupted, and so machine productivity is maximized.

The cutting tool is typically mounted on a carriage that moves either parallel to the product flow or at an angle across the product flow. The flying shear drive accelerates the carriage to synchronize with the line speed, while synchronized the cut is done and the carriage then decelerates and returns to its original position ready to cut again. There are also many other similar applications where a carriage must be synchronized at line speed and most of these can also be accommodated using the flying shear application software.

Typical applications include various types of cut-to-length machines, depositors, punches, product inspection, or any other process where synchronization at line speed is required.

A machine extrudes plastic pipes that must be supplied to the customer in pre-cut lengths. The extrusion process requires the extruder to run at a continuous speed to maintain the quality of the product. The pipe is uniform along its length and provided the length is within a set tolerance then the pipe is fit for sale. The flying shear is used to cut the product cyclically.

The actual design of the machine that we observed in the mill was very large in size and it cut the hot billets of diameter 1\2 inch to 1 inch and length will be in several meters and it cost thousands of dollars we cannot make this machine as FYP. So according to the situation, we had to design a machine of a small size to cut something other than a hot billet. We chose the design of the printer as a model as the design idea was similar to the printer and select copper wire as a job. The sketch will be shown below.

The Cold Rolling Mill

The Cold Rolling Mill

In the article How Many Types of Rolling mill, we know that rolling is divided into two types that are hot rolling and cold rolling according to the different temperatures when metal is rolled. If the temperature is above its recrystallization temperature, then this kind of process is known as hot rolling. If the temperature is below its recrystallization temperature when mentally rolled, the process is called cold rolling.

While this article mainly talks about cold rolling. Cold rolling is fulfilled by making steel strips through plenty of tandem rolling mill stands. And each one of the stands has vertically stacked rolls that are powered by a huge motor to impart high compressive stresses into the strip. While hot rolling, pickled coils fed into the cold rolling mill from an entry-end reel and progressively reduced in thickness in each stand, to achieve the final desired thickness, as the strip exits the last stand. After the last stand, the strip recoiled. At this step, the strip is highly cold and not very useful for most applications. It needs to be annealed to soften the steel and make it more formable. 

Another method of cold reduction needs to use of a reversing mill. In this process, the strip is passed back and forth between mandrels on each side of a single or two-stand mill. The strip is reduced in thickness on each pass until the final required thickness is attained. The typical percent cold reduction ranges from 60 to 80 percent; such reducing a hot rolled strip of 0.100-inch thick to a 0.030-inch thickness results in 70 percent cold reduction.

The Concept And Process Of Rolling Mill

The Concept And Process Of Rolling Mill

Steel is widely used in our daily lives and holds a critical position in the national economy and most of the steel products we need are produced by rolling mills. The rolling process plays an important role as the final link of the steel-making process in modern steel enterprises.

Steel rolling, as its name, is a process of shaping the steel billet with rollers. And the rolling mill is what you need to get the job done. The complete rolling production process contains a series of different rolling techniques and it can be complicated. However, despite all those various requirements, the basic production process always contains the following procedures: reheating the steel billet and further treatments, rolling process, and the final finishing rolling process.

When the billets arrive, they need to be treated with chemicals like acids to remove the oxidation film and the obvious defects on the surface must be removed too. Then the billets will be reheated to a certain temperature to be ready for the coming rolling process. The rolling process is the core of this whole production, the billets will be rolled into different shapes and the rolling technique is crucial for the quality of the final product. It must meet the requirements from three different aspects: the product’s geometry dimension accuracy, internal organization, and performance, and clean and smooth surface. 

After all these processes, the product still has a complicated finishing rolling process. As a guarantee of the product, the finishing process can be different for the various requirements and standards. After the cooling, straightening, heat treatment, and other certain process procedures, the final product will meet all those customized requirements.