Displaying the prowess of
our solutions capability in a true blue steel plant
BMM Ispat Ltd. is an INR 2000 crore (USD 330 million) company. Their plant at Danapur, Hospet, Karnataka is a true blue steel plant manufacturing high quality steel products. As a part of a new brownfield project, the company is expanding its capacity from 0.8MTPA to 1.25MTPA. This facility is being constructed to expand the product range and will include a semi-automatic process for enhanced productivity.
The plant is spread over a vast area of 50 acres (approx. 200,000sq.m.), with the manufacturing process divided into four stages.
In the SMS, raw material is melted to form billets of desired shape and size. Ladles are used to handle the metal in molten form. The formed billets are to be rotated by 900 and transferred on to idle rollers to take them to one of two different storage locations.
The process involves handling of metal billets that are 12m in length on average, over a 200m long bay. The process is initiated by passing the billets from the furnace on to idle rollers installed beside it. Preheated billets are then passed through various horizontal and vertical rolling mills to give them the desired shape. Cranes in this area are also required to frequently change the dies of the presses to suit the product being rolled, which include rolled angles, TMT bars, metal rods and I-beams.
Here, the products are rapidly cooled, which produces a harder material and prevents low temperature processes such as phase transformation in the material. The products are further cooled and then sent for the final finishing process.
The despatch yard is spread over a 380m long and 50m wide area. This consists of parking bays for trucks and a railway track for loading on railway carriages. Long rods and beams are required to be handled and stored in the despatch area. Cranes with rotating crabs are used to control the angle of long metal bars and other similar components in the despatch bay.
BMM Ispat was looking for a competent partner who could understand these challenges and design a complete material handling system to integrate the various processes. The objective was to ensure safe, quick and precise handling through the processes and appropriate manoeuvring in the despatch bay.
When BMM Ispat chose to entrust the responsibility of supplying cranes for their plant to ElectroMech, our engineering team was enthralled with the challenge. Unique crane solutions were designed to efficiently integrate the plant while withstanding high operating temperatures. All this, while ensuring high levels of safety, reliability and cost-effectiveness.
ElectroMech responded to BMM Ispat's challenge with some unique ideas. Detailed analysis, design and iterations resulted in an integrated solution that achieves the intended tasks swiftly and in the most optimum manner.
A total of 13 cranes were designed to handle the material through various processes, right from the steel melting shop to the placement of bars and rods on railway carriages.
In the SMS where billets are formed, a total of 4 cranes with rotating trolleys assist in the manufacturing and storage of the billets. Two 20MT, 32.8m span and two 20MT, 27.2m span cranes with rotating crabs cover the manufacturing and storage of the billets before they are sent for further processing. Since these cranes are part of a process and in constant use, they are designed for M8 duty.
The ambient temperature in the steel melting shop is approximately 600 C, requiring all the components of the crane to be able to withstand such high temperatures. Hence, a slewing wheel on curved rail type of arrangement was selected to be able to work in this area. An air- conditioned cabin is also provided for the operator.
The furnace is served by a 10MT crane with 22m span, which also has a rigorous initial application of installing the furnace and rollers. Once the installation of the furnace is completed, the crane will be used for replacing the rollers and for regular maintenance applications.
Two Double Girder cranes serve this area, one 25/5MT, 28m span and one 20/5MT, 34m span. Since the dies have to be changed depending on the product to be manufactured, the 25/5MT crane is in constant use. All these cranes are designed for M7 duty.
The material to be handled in this stage is in the form of bundles. Here, two 15MT, 28m span, M7 duty, Double Girder cranes are installed to handle the material being processed in this bay. These cranes will also assist in the installation of the machinery during plant set up stage.
The despatch bay is served by three 12.5MT, 34m span, M7 duty cranes. Like the steel melting shop cranes, these cranes also have 3600 rotating crabs, however, the mechanism used here is a slewing bearing. This mechanism was narrowed down upon after many discussions between ElectroMech's design team and the BMM team.
Two types of rotating mechanisms were finalised - one operating with the help of gears and a slewing bearing, the other, using curved rails and wheels. The slewing bearing arrangement was selected for the despatch area since the cranes will be used for continuous operations and hence the maintenance had to be kept to the lowest possible. The cranes in the Steel Melting Shop need to operate continuously as part of a process at an ambient temperature 0 of 60 C, requiring easy accessibility and simple mechanisms. Hence the wheel on curved rail type of arrangement was selected for this area.
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