What is in this post?
In this post we have shared some important knowledge about LRF technology and it's benifits in making quality steel bars and billets.
In order to produce the best quality TMT steel bars, it is important to control the proportion of Sulfur and Phosphorus in it. The presence of these chemicals in higher proportions reduce the ductility of steel and create inclusions which result in disastrous imperfections.
LRF technology refines and purifies the steel by reducing Sulphur, Phosphorus and dissolved gas levels as per BIS norms to provide strength and flexibility.
What is the LRF Technology?
Ladle Refining Furnace (LRF) technology is a state-of-the-art method which is used to desulfurize and dephosphorize steel and remove other impurities and subsequently to produce high quality steel. In this method a Ladle Refining Furnace is used to raise the temperature and adjust the chemical composition of molten metal.
Ladle Refining Furnaces (LRF) are used to hold the molten steel for casting operations. In most metal-melting operations, large ladles are used to transfer molten metal from melting furnaces to refining or pouring stations.
In short, we can say that the Ladle Refining Furnace technology is a proven technology which used to improve the quality of liquid steel through refining and purifying of its chemistry.
What is Ladle Refining Furnace?
The Ladle Refining Furnace is a furnace in which the quality of liquid steel is improved by raising the temperature, to create a more refined grade of steel.
The Process of LRF Technology
The Ladle Refining Furnace process can be applied during steel production, once the basic steel has been produced from iron in an oxygen furnace, arc furnace or induction furnace.
Then the steel is transferred to a large ladle for further refining, chemistry adjustment, inclusion and modifications.
The ladle is provided with a heat source. It increases the temperature of the heat source and adjusts the chemical composition of molten raw metal.
As the ladle increases the heat of the liquid metal, it compensates thermal losses and further refines the steel.
Finally, the specified chemistry is obtained by adding ferro-alloys and the liquid steel is sent to the caster. This refined steel is cast into billets of required sizes in closed environment, to have further control of any remanent gases and other inclusions.
In other words, LRF is a furnace in which the quality of steel is improved by refining and heating. In the field of process metallurgy, refining steel in the ladle is known as secondary metallurgy.
Benefits of LRF Technology
There are many benefits that accrue from using the Ladle Refining Furnace process to refine steel. These includes
- The LRF process desulphurized and dephospherised the steel.
- In the LRF process, the steel is made cleaner by removing the oxide inclusions.
- The gentle stirring by the ladle results in homogenization of the temperature and the composition of molten steel.
- Inert gas purging helps in degassing of the steel and achieve low gas (oxygen, nitrogen and hydrogen) content.
- Improving grain refinement in the microstructure.
- Through better recovery and maintaining composition in narrow range, there is ample saving on ferro alloy consumption.
- When the temperature is low there is increase in productivity as the melting furnace gets emptied faster.
- LRF acts as a buffer by holding molten steel for sequencing on the CCM.
- Without LRFs, higher tap temperatures are normally required from steel making furnaces due to heat losses during refining with conventional ladles.
- At present, the Ladle Refining Furnace process is the most effective method to produce high quality TMT bars of Grade "D" as per IS: 1786 norms.
- As a result of LRF technology, one gets higher quality Fe 500D or Fe 550D grade TMT steel bars.
With the thrust of infrastructure development, there is huge demand for construction grade steel, which is strong, ductile, anti-corrosive, earthquake-resistant, fire-resistant and high durable. TMT steel bars that are produced using superior LRF technology meet all these specifications.
