Head Hardened Rails

160


Ramesh Ajmeria,
Executive Vice President,
Jindal Steel & Power Ltd.

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Introduction:

India is the world’s third-largest producer of crude steel (up from eighth in 2003) and is expected to become the second-largest producer. The steel sector in India contributes nearly two per cent of the country’s gross domestic product (GDP) and employs over 6, 00,000 people. The growth in the Indian steel sector has been driven by domestic availability of raw materials such as iron ore and cost-effective labour. Consequently, the steel sector has been a major contributor to India’s manufacturing output. The Indian steel industry is very modern with state-of-the-art steel mills. It has always strived for continuous modernisation and up-gradation of older plants and higher energy efficiency levels. Presently, India’s crude steel capacity is around 126 Million Tonnes (MT) and Production of crude steel was 97.4 MT during 2016-17.

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The Indian Railways is the transportation lifeline of India. With the new impetus on railway infrastructure development there is a pressing need for indigenous capabilities to be enhanced in order to meet the growing requirements of a billion plus population in India. Industrial growth and development warrants that Indian Railway facilities continually innovate and steel manufacturers play a pivotal role in contributing to the overall holistic development of rails in India.

Because of increases in train speed and freight car capacity aimed at improved efficiency, rails are subjected to severer conditions than ever. The tonnage of trains has increased markedly, and the axle load and tangential force or impact force applied to the rails by the wheels have become exceedingly great.  Recognizing the increasingly severe service conditions for rails, in 1976 Nippon Steel developed a new head hardened (NHH) rail that is continuously slack-quenched by air after being subjected to induction heating. In 1979, the company developed NS-II rail (Super rail), the purpose of which was to prevent the welded joints from softening.

Transportation is one of the pillars of sustainable development of any developing country particularly in India which have huge population and world’s fastest growing countries. Railways have most contributing and play an important role for economical, safe and large quantity transportation of goods and human. For healthy transportation rails of the best quality are necessary to ensure the reliability of the track. To meet the current requirement of transportation more and more trains with higher loads and higher speeds results chance of wear and tear in rail tracks.

Jindal Steel & Power Limited is of India’s leading steel producer with a significant presence in power generation, mining and infrastructure. With an annual turnover of US $ 3.38 billion as on 31st March, 2017, JSPL’s business orations span across Asia, Africa & Middle East and Australia.

Since 2003 JSPL has been manufacturing rails for more than 14 years. JSPL rails are highly rated in India and Abroad. They meet the domestics demand as well as international standards. JSPL rails are available in various sizes and grades so that they can be used for diverse applications such as track rails, crane rails and high speed rails.

Keeping in view the importance of the significantly growing rail sector in India as well opportunities in infrastructure development JSPL has established and produced world’s longest 121m rail tracks. JSPL has developed and improved operation efficiency for producing longest rail 121 m in 13 m class A rails for DMRC and Kochi metro as per IRST 12 (2009) specification and successfully dispatched 260m welded long rail panels to DFCC for the first time in India.

In pursuit of bringing the world’s best to India, production of rail at JSPL was commenced with technology collaboration with M/s NKK corporation (now known as JFE corporation). Further in line with international practice with to flash butt weld rail panel at manufacturing plant itself, an integrated long rail flash butt welding line is in installed. The state of the art steel making technology insures high quality low inclusion levels in rail steel meeting the requirement of national and international standards of rails such as IRST 12 (2009), EN 13674-1 (2011) and UIC 860R.

JSPL Rail Manufacturing Features:

  • Rails are produced by the Universal modern Rolling mill which ensures the highly symmetrical cross sections with superior quality.
  • With the state of art technology and facilities, producing uniform rails.
  • JSPL produces high performance rail products in various specifications like UIC, IRST-12(2009), EN13674-1 and other international specifications.
  • Inspection of rails by third party agency RITES.
  • Welding of Rails by world’s top class technology by Flash butt welding with stringent quality norms by RDSO.

 Tandem Mill Facilities at JSPL Raigarh:

The JSPL Mill has the distinction of being one of its kinds and produces structural products like beams, columns, channels, angles, sheet piles, H- beams and Rails (Track rails & crane rails). We also have NABL accreditation for testing of rails viz. residual stress, Fatigue test, and TLT, USFD and fracture toughness. Its strong focus on quality assurance systems are equipped with modern testing facilities for online and offline testing conforming to stringent quality standards.


              Tandem Mill facilities at JSPL Raigarh.

Development of Head Hardened Rails in JSPL Raigarh:

JSPL has played a pioneering role in the indigenous product development of Rails and is embracing state of the art technology to produce world class rails. Innovation and new product development lie at the core of our Business culture and this ethos transcends across all our operations.

JSPL is the first and the only indigenous steel major to have developed the head hardening facility; which is a game changing initiative in the rail industry. Hitherto, head hardened rails were being imported from Europe and Japan for use in Metro Rail and new projects in India. JSPL being the only producer of Head Hardened Rails in India is poised to play a significant role in the growth of India’s Rail Infrastructure.

High Speed Train:

In keeping in mind with the Government’s – Make in India Program, we envisage increased demands of rails for use in high speed, heavy haulage and mass transit lines, which require maximum durability against wear and material fatigue caused by escalating train frequencies, speeds and axle loads. Head Hardened Rails are used in high speed rails (> 250 KM/Hr.) for Bullet Trains. These Rails are also used in heavy traffic and axle loads for freights and Metro rail. These Rails with enriched wear resistance are used for high speed, Metro Rail, Bullet train and Heavy Haul applications.

JSPL established in setting up Online Head Hardened Rail with technical consultation with SMS Meer, Germany and successfully commissioned its Head Hardened Facility in May 2016. JSPL started the commercial production in 2017 for the first time in India and obtained the TUV NORD Certification for Head Hardened Rails of grade 1080 HH and 350HT grades. The Head hardened process would include Tilting of Rails after tandem mill, Induction Heating as required and water spraying through Selective Cooling technology. These would have higher resistance to wear and is made possible with greater hardness of rail head, which is the upper part of a rail and supports the wheels of railroad cars.

Selective Cooling by Rail Cool Technology by SMS Group:

  • Homogenization of the temperature profile
  • Minimisation of the intrinsic stresses
  • Improvement of the rail straightness
  • Heat treatment in line downstream of the rolling mill

JSPL Raigarh produces head harden rails having excellent metallurgical and mechanical properties such as higher wear resistance due to top of the rails having higher hardness and finest grain structure and size. Micro-structural evolution has been control by selective cooling system at top of the rail. JSPL produced rail having higher ability to handle axle load with low deformation due to good operational control during manufacturing process.

         
              Selective Cooling at top of Rail (Rail Cool Technology JSPL Raigarh).

   
                                JSPL Raigarh Produced Head Hardened Rail.

Head Hardening technology is a cost-effective and efficient method for extending the service life of rails by improving mechanical properties. The higher resistance to wear is made possible with greater hardness of rail head hardening. To meet the demand of faster high speed rails, JSPL has opted new application technology “Rail Head Hardening” with sophisticated laboratory facilities. Head hardened rails can withstand increased wear from trains travelling faster, at greater frequencies and with heavier cargo. With hardness levels of 340-390 BHN, head hardened rails have a longer lifespan and are safer. Continuous improvement on the speed and loads of the passing trains are placing more and more demands on the performance of the rail. It is significant to prolong the service life of rails in a cost effective manner – this can be done by improving the properties of the rail, which is fortified by the Rail Head Hardening process.

Specification of Head hardened Rail:

SPECIFICATION GRADE HARDNESS UTS (MPa)
IRS T-12 (2009) Normal Grade (1080) ≥260 BHN 880
Head Harden Rail (1080HH) 340-390 BHN 1080
EN 13674 (2011) Normal Grade   (R-350) 260-300 HBW 880
Head Harden Rail (R-350HT) 350-390 HBW 1175

 

  • Length of single piece rail is 80m.
  • HH Rail Profile: UIC-60, UIC-60E1, IRS-52 etc.

Certifications:

  • BSI-London for Quality (BS: EN 9002:2000)
  • Environmental management system (BS EN 14001: 1996)
  • RDSO (Indian Railways) – For Flash Butt welding parameters.
  • NABL accreditation lab for testing of Rails: All Qualifying and Acceptance tests for Rails are done at JSPL as per IRS-T-12(2009).


                              Certificates of TUV NORD for head harden rail.

The head hardened rails are different from normal rails.  First, Head Hardened Rail can withstand increased wear from train travelling at high speed (>250 km/Hr) and greater frequency with heavy axial load. The higher wear resistance is made possible by increasing hardness at head of the rails which also gives good abrasion resistance. Second, longer and sturdier rails with fewer joints are needed on the track.

Third, cost effective with higher lifecycle and better weldability etc.

Process Flow Diagram of Rail Manufacturing:

                    

Cross Section profile of UIC-60 and UIC60 E1:

Installation of New Straightening Machine:

JSPL installed straightening machine supplied by SMS-Meer with Level-2automation for straightening of Rails and Structures with the state of the art technology. The 9 roll horizontal and 9 roll vertical straightening variable pitch for controlled residual stresses in finished rails. Change-over times are reduced to a minimum by automated change systems which gives the maximum mill utilization, and process flexibility to produce a wide range of sizes and grades, resulting in products of high quality in tolerance, metallurgical properties and surface condition.

 


                     Installation of New Straightening Machine in JSPL Raigarh.

Advantages of Head Hardened Rails:

  • High Strength
  • High Wear Resistance
  • Low residual stresses
  • Prolonged service life and enhanced safety
  • Economical and Cost Efficient with High Lifecycle
  • High resistance to deformation caused by compression
  • High resistance to brittle fracture
  • Low residual stresses after manufacturing and straightening
  • Good weld ability.

 Indian Railway Development Plans and Projects in 2018:

Finance Minister in the Union Budget 2018 speech said that developing infrastructure – including railways – would continue to a priority for the government. From world-class train sets to bullet trains and revamp of signalling systems and providing CCTVs and Wifis – FM  portion of Union Budget speech dedicate to Railway Budget helped several promises that aim at transforming Indian Railways.

These are the main points that the budget for Railways 2018 focused on:

  • Rs 1.48 lakh crore has been allocated for Indian Railways. Most of this capex will be dedicated to capacity creation.
  • For Mumbai local trains, an amount of Rs 11,000 crore has been allocated to add 90 km of double line tracks.
  • 18,000 km of doubling, third and fourth line works and gauge conversion of 5,000 km would be done in order to eliminate capacity constraints. In addition to that, complete conversion of entire network into Broad Gauge to take place.
  • Track infrastructure is necessary as safety point of view so for that the government has targeted over 3,600 km for track renewal.
  • In addition, 150 kilometres of suburban network is being planned at a cost of over Rs 40,000 crore, which will include elevated corridors on some sections.
  • A 160 kilometres suburban network at an estimated cost of Rs 17,000 crore is provided for the growth of the Bengaluru metropolis.
  • An institute to train manpower for high speed rail projects will be set up in Vadodara, as the foundation stone of Mumbai-Ahmedabad bullet train project, India’s first high speed rail project was laid last year.

Conclusion:

  • Continuous innovation in plant, technology, research and development, combined with the unrivalled metallurgical knowledge and track design expertise, ensure that JSPL Steel delivers the high-performance rail demanded by today’s rail operators.
  • Process innovations and product development initiatives at JSPL are focused unwaveringly on delivering the high-performance rails required to support advances in train technology, as well as meeting the longer in-service product life and reduced maintenance costs demanded by rail network operators.

The rolling mills at JSPL use the latest process technology, computer modelling, computer-controlled heating and cooling, and novel roll-pass design to produce exceptional quality head hardened rails. The advanced testing and finishing systems that complete the JSPL rail manufacturing process ensure that all rail products meet the high standards required for all rail applications – from high-speed and heavy-haul networks to urban and industrial railways.

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