Introduction
The legacy of Indian Railways is more than a century old which makes it the fourth largest railway network in the world. Under the British Raj, the first train ran between Mumbai (Bori Bandar) to Thane on 16th April 1853. Indian Railways serves the huge population of the country in the means of passengers and goods transportation. Up to 24 million passengers travel daily by train and provide connectivity between rural & urban areas of India.
Since the commencement of Indian Railways, many different types of engine technology have been used. But the question arises why there was a need to develop a high-speed rail network. To answer that we need to go back in time, till the early 90s steam locomotives were used by the Indian railways but due to various reasons like low efficiency, pollution, speed (due to narrow gauge lines) & high maintenance costs became the prime reason for their discontinuity.
In today’s era, the railway tracks are standard gauges where mostly diesel & electric engines are being used by the Indian railways, which helps in achieving fuel efficiency as well as speed. Low carbon emissions are a goal set by the leadership of the country where Indian railways have successfully introduced CNG-based rail engines which are cost-effective as well as emit low carbon.
Looking into the need, the Government of India has signed an MoU with the Government of Japan to develop a high-speed railway corridor in India. The first bullet train will run between Mumbai to Ahmedabad. The Mumbai Ahmedabad High-Speed Rail (MAHSR) corridor is an under-construction project that is expected to be finished by 2026 where the train will cover 508 km (12 stations) in just two hours. The development in terms of land acquisition is nearly done, simultaneously 162 km of piling work & 79.2 km of pier work have already been finished.
Role of Welding in Building High-Speed Rail Network
Welding plays an important role in any metal fabrication, as it gives a lasting solution than any metal joining process. In the railways, welding is majorly used for joining tracks, coaches, wagons, bridges, and for miscellaneous metal works. In the project of building the high-speed rail, we will be focusing on the welding of the train and the structure on which the train will run.
Building the railway coaches is a major responsibility where no errors can be made because these high-speed trains will run above 300 km/hr of speed. In manufacturing the coaches several welding processes are used such as GMAW, SMAW, GTAW, etc. The coaches are manufactured in a dedicated coach factory where all the metal frames (made up of aluminum, SS, etc.), wheels, suspension system, brakes, electric motors, etc. are joined together.
To achieve accuracy in dimension & quality, welding is done by the robots where the settings of different programs are fed and implemented. Although the programs are set, strict monitoring of welded joints is done to avoid any error.
Once the welding of the side frames is done along with the water tanks with the TIG process, then the final grinding takes place where the surface of the welded joints gets smoothen. Once these coaches get ready to be placed on the track, the final inspections take place where the Non-Destructive Test (LPT, RT, UT) is done to identify any welding errors.
Moving on toward the track on which the train will run, the MAHSR project is based on the Japanese Shinkansen track technology which will help the tracks to withstand earthquakes and other natural calamities. We are aware of the fact that whenever a train passes, the rail joint sections are subjected to mechanical shocks which can create stability concerns for the train. This is why the bridge concept is being used for the MAHSR corridor where the priority is to reduce and minimize these mechanical shocks. Hence in this case the improvement was needed in the welds to make sure that the weld joints are stable to keep the trains efficiently passing.
For the MAHSR corridor, seismic stopper applications will be installed on the tracks, these seismic stoppers are mainly based upon the concept of Vibrations Control Device (VCD) with the capability of giving a stable stage to a bridge and mainly absorbing the vibrations and preventing the structural collapse.
The MAHSR corridor will consume up to 10,000 metric tonnes (MT) of fabricated girders to support the load-bearing capacity of the steel bridges which is going to support the structure. The bridges for the bullet train are being built with modern welding technology where various welding consumables like filler wires, CO2 wires, SAW wires & fluxes are going to be consumed. As we are aware of the fact that welding provides more lasting solutions than any other metal joining process which will allow the train to run at a speed of 320 km/hr without any worries.
D&H Sécheron’s Welding Solutions for High-Speed Rail Network
D&H Sécheron Electrodes Pvt. Ltd. is a 56 years old organization where developing products according to the customer’s needs are kept on priority. We provide complete welding support to our customers from manufacturing the consumables to any technical support which has become one of the major reasons for developing more than 800 products.
For the development of the first bullet train project in India, D&H Sécheron is providing various welding consumables for the project, let’s dive deep into it:
- F 70S-2: A ER70S2 triple deoxidized copper-coated mild steel wire for GTAW, which is available in a bright finish, gives smooth flow, stable arc, and spatter-free under optimum welding conditions. It gives radiographic quality welds and is suitable for root run of mild steel pipes.
- Autotherme-1: An ER70S-6 copper coated mild steel GMAW wire for welding of mild steel, low carbon steel, and other structural steels of tensile strength up to 540 MPa. The wire burns with a smooth arc and minimum spatter under optimum welding conditions. It is designed for single and multi-pass welding of low and medium-carbon steels.
- Autotherme Grade-E: An EH10K copper coated high manganese special wire, which needs to be used in combination with acidic as well as a basic flux for the welding of structural steels and fine-grained steels requiring, 480MPa tensile strength in the stress relieved conditions.
- Maxflux SAF-7S: Is a high-speed welding acidic agglomerated flux for spiral pipe welding. The flux is suitable for single & multi-pass welding with single wire & multi-wire applications in both AC & DC polarity. Slag detachability is good and deposited weld metal is of radiographic quality.
Maxflux SAF-7S is suited for fabrication and welding of spiral pipes, smaller diameter pipes (internal and external), penstock pipelines, pressure vessels, girders, earthmoving equipment, structures of off-shore platforms, etc.
Conclusion 
D&H Sécheron is continuously working towards providing the best consumer satisfaction. Our unparalleled team of sales engineers, front liners, R&D, and various technical & non-technical crew works day & night to offer strong support and backup to all our customers. Our constant approach towards innovation and development of welding consumables resolves every joining or hardfacing requirement of numerous industries around the country.
D&H Sécheron Electrodes Pvt. Ltd. provides its services to various governmental organizations where Indian Railways is our key partner, there are several products approved by the RDSO which showcase our consistent delivery of welding consumables. To get complete welding support feel free to drop us an email at info@dnhsecheron.net or call/WhatsApp us at +91-98335 50505 or visit our website www.dnhsecheron.com , we will be happy to answer all your queries.
