INDUSTRAL VISIT on 09/11/2022

INDUSTRIAL VISIT on 09/11/2022

About the visit to Salem Steel Plant:

35 students studying 3rd Year (2022-2023) in the Department of Electrical and Electronics Engineering at SRM Valliammai Engineering College along with two professors’ of EEE Department named Mr. V. Sudhagar and Ms. S. Vanila have visited the Salem Steel plant, a special Steel plant of Steel authority of India Limited, under the Ministry of Steel, Government of India, on 09th November 2022. The entire industrial visit was guided and instructed by Mr. P. Velumani, Assistant General Manager (Electrical Department), Hot Rolling Mill division, SSP. Details of the Salem Steel Plant and the areas visited during the Industrial visit were discussed in detail below.

INTRODUCTION TO SALEM STEEL PLANT

Salem Steel Plant is one of India’s leading producers of quality Stainless Steel. The Plant was commissioned in 1981. “Salem Stainless” has become a household name in India. SSP products are also widely exported.

The entire Salem Steel Plant is certified with ISO 9001:2008 for Quality Management System (QMS), ISO 14001:2004 for Environment Management System (EMS), OHSAS 18001: 2007 for Health Services, SA 8000:2008 for Social Accountability, ISO 14001:2004 EMS for Township also.

Hi-tech industries like atomic power stations prefer ‘Salem Stainless Steel’. The products from SSP are widely used in industrial sectors like Dairy and food processing, Chemical and fertilizer, Heavy engineering, Railways, Automobiles, Bulk solid handling, Power etc. The building and architecture segment, which is growing at a rapid pace, sees ‘Salem Stainless’ as the most dependable companion.

In architecture, building and construction, the prestigious structures were ‘Salem Stainless’ was used include the parliament House Library complex, New Delhi, the world’s tallest Petronas Twin-Towers, Malaysia and the retractable roofing at Melbourne Tennis Stadium, Australia. The coaches of the Jan–Shatabdi

Express trains are furnished with modular rail marts and sub-pantries made entirely of ‘Salem Stainless’. Korean blue resin coated corrugated curved roofing of the Koparkhairane Railway Station in Navi Mumbai is a trend setter for railways in India.

SSP supplies 409M, a special grade of stainless-steel sheets to Indian Railways for fabrication of wagons, for handling coal, etc.

Picture taken on 09/11/2022 at Salem Steel Plant

MAJOR DIVISIONS OF SALEM STEEL PLANT

1. Steel Melting Shop (SMS) (Exempted for Visit)

2. Hot Rolling Mill (HRM)

3. Cold Rolling Mill (CRM)

4. 230Kv/33Kv Substation

From the above division, the Industrial Visit were undergone only in Hot Rolling Mill, Cold Rolling Mill and Substation. SMS is a risky area, so the students are not allowed to visit that division. Areas visited were explained below,

HOT ROLLING MILL DIVISION

The Hot Rolling Mill was commissioned in November 1995. Installation of additional roll grinding machine in hot rolling mill to increase hot rolling capacity to 3,64,000 TPA.

The major equipment in Hot Rolling Mill is

1. Walking beam type Reheating furnace

2. Primary De-scaler

3. Reversing Edger and Roughing Mill

4. Reversing Steckel Mill (Finishing Mill)

5. Laminar cooling

6. Down Coiler

PROCESS:

Slabs of carbon steel or Stainless steel are received through wagons/ trailers and stored in slab yard. As per the schedule the slabs are charged into the Walking Beam Reheating Furnace and heated to the discharge temperature of 1150˚ C to 1250˚ C depending on the grade.

These slabs are discharged from furnace and the primary scales are removed by means of high-pressure water at primary descaler. Then the slab thickness is reduced by rolling in Roughing Mill to a thickness of about 25 mm, which is called Transfer bar (T-bar) in 5,7 or 9 passes depending on input slab thickness.

The head end and tail end of the T-bar from Roughing Mill are cut in rotary Drum Shear before further rolling in Steckel Mill. Having achieved the required final thickness in 3, 5 or 7 passes as per the pass schedule, the strip is cooled by laminar cooling system in RORT and wound in Down Coiler mandrel. After strapping, weighing, and marking, the coils are taken out from conveyor and dispatched to CRM or customers.

Workflow Diagram of HRM Division

COLD ROLLING MILL DIVISION (CRM)

Cold rolling Mill (CRM) was installed as two phases with two different capacities of producing output. CRM is the biggest mill in the Salem steel plant. In CRM the precision in output steel sheets and coils were acquired. The process of shaping and rolling in room temperature represents the name Cold rolling Mill.

ANNEALING AND PICKLING LINES:

Two annealing and pickling lines are provided for processing hot rolled strip and cold rolled strip at intermediate and final stages. One continuous Annealing & Pickling Line is envisaged for processing hot rolled strip of thickness 2 to 7 mm. Capacity of A&P line is 5,00,000 tpa. Annealing is done to relieve the stresses & formation of new grain. Pickling is done to remove the scales which are generated during annealing.

Phase 2: Installed capacity of CRM is 70,000 Tonnes / Annum. Process Flow of Cold Rolling Mill Phase 1: Installed capacity 32,000 Tonnes / Annum

COIL PACKING & DISPATCH

For Prevention from the dust and defects during storage and transportation, proper packing should be done. For export and house material different type of packing is required. Packing also depends on the thickness of the material. For packing of different grade and thickness material we are using following materials. PVC Coating, Interleaving paper (ILP), Bubble sheets, wood and metallic pillars and Oil sheets. Less than 0.63mm coil should be covered with GI sheets. 1.2 mm or less coil, inner ring provided, and upper coating should be GI Sheet.

For special finishes like No.4 hard boards are used both sides top and bottom side. Packing strap is used for coils having 0.7mm thickness and widths are 19mm and 32mm. Other parts of this line are conveyer, weight section and strip packing section.

COIN BLANKING LINE

The purpose of Blanking line is to produce polished coin blanks and utility blanks. Blanking facilities supplied by M/S Schuler, Germany has an installed capacity of producing 3,000 Tonnes of coin blanks or 3,600 Tonnes of utility blanks per annum. It was commissioned on December 24, 1993. The high-speed blanking press can punch out about 600 Kg of coin blanks per hour at a speed of 600 strokes per minute. These blanks after being de-burred and degreased are rimmed in a rimming machine.

The double drum rotary furnace anneals the blanks in a protective nitrogen atmosphere. The centrifugal pickling and polishing equipment have a rotary drum where the coin blanks and stainless-steel balls are rotated at high speed. The coin blanks are then counted and packed.

STEEL PLANT’S SUBSTATION

Salem Steel Plant (SSP) power demand is very much higher as they were using Electric Arc furnace for melting the scrap in Steel Melting Shop (SMS), it requires more than 50,000A of current to produce arcing, also they are using 4 motors 4.5 Mega Watts (two motors) and 3.5 Mega Watts (two motors). To meet out this high electricity demand Steel authority of India Limited, Salem Steel Plant has installed their own 230KV/33KV Main Receiving Substation in the plant premises.

CONCLUSION

The industrial visit to the Salem Steel Plant was very useful for the students to connect with their curriculum and the industrial application of the Electrical Drives, power Transmission, PLC Automation, and the management of power in a large-scale industry, was seen by the students directly in the Salem Steel Plant premises. Students can relate this and study in the upcoming semester of their curriculum.