Galavanised steel proves to be economically viable for lighter and safer body construction
Regulations in Europe, USA and various other advanced markets call for the use of galvanised steel in the manufacture of car bodies. The benefits of this include the ability to withstand corrosion for long, and thus allow lighter and safer body construction. At a recent event organised by Hindustan Zinc in association with International Zinc Association (IZA), attention was drawn towards the tendency of Indian manufacturers to use coated steel over galvanised steel to manufacture car bodies for local sale. With India poised to become the fourth largest car manufacturer by 2020, and a manufacturing hub for small cars (including a global design centre for small cars), the fact that cars sold in India up to Rs.10 lakh do not use galvanised steel in their body construction. The non-galavanised Indian cars incur high maintenance and will not be withstanding super-crashes.
“The fact that the use of galvanised steel is limited to car bodies that are exported out of India, while Indian cars get churned out as non-galvanised variants which deem our roll-outs ranked a step behind the other exported cars,” mentioned Kenneth De Souza of International Zinc Association – Global, while speaking at the event. “I know many a car owners would readily vouch the fact that corrosion makes its way in a matter of few years after purchase, which in-turn affects their pockets either on mending or replacing the parts,” he stated.
What makes it necessary for manufac- turers to use galvanised steel on cars exported are the regulations in those markets which call for it. This often leads to the manufacturers in India doing an export run at the plant, halting the line and cleaning the dies, and then starting with the Indian run according to De Souza. De Souza added, “There is an amount of cost saving achieved with the steel body coating with the usage of welding currents comparatively low to that of zinc coated bodies.” Drawing attention to the use of galvanised bodies for decades across Europe, North America, Japan and Korea, De Souza said that vehicle buyers in such market are given ‘Anti-corrosion and Perforation warranties’ for as long as 15 years. He touched upon the movement started by Ralf Nader in US to demand cars that would last longer rather than have their bodies lose to corrosion in a couple of years, and which turned into a national movement, leading to an manifold improvement in the reliability of cars.
Advocating the use of galvanised steel in the construction of automobiles, Dr A S Khanna, Professor , IIT Mumbai, drew attention towards the use of galvanised steel in the construction of buildings and structures. While he claimed that the same is bounded by regulations, he stated that a detailed analysis was done by his team. A sample of 500 cars was identified for the study in Mumbai. These cars were in the price band of Rs 5-10 lakh and 5-10 years old. The study results depicted that the resistance to corrosion of a vehicle body, made of steel sheets, can be increased manifold by the use of galvanised steel. The cost differentiation will be very less and affordable even when galvanised steel becomes a regular
fit in the car . Khanna averred, “Though the tests were restricted to passenger vehicles, the findings also stand true for diverse product portfolios such as two wheelers and commercial vehicles.”
Categorising corrosion issues in vehicle bodies as blisters, surface rust and imperfections, Khanna opined that four areas most susceptible to corrosion were the bonnet (hood), boot (deck lid) or hatch, rocker(sill) panel and door panels around handles. The research, according to Khanna, also stated that out of the 5 year old cars, more than 60% were found to have a problem of surface rust. “Surface rust not only reduces steel strength, compromising safety in an event of impact but also affects the fuel efficiency resulting high emissions that would lead to a reduction in the Total Cost of Ownership (TCO). The argument further stems from the fact that galvanised cars have demonstrated significantly improved performance; to the tune of 70% higher than non-galvanised cars of the same model rolled out in the same year,” exclaimed Khanna. He further said that a car with a galvanised steel body (with 5 year anti-perforation warranty) would need a paint touch-up in 5 years, with Rs 9000 saving when compared to non-galvanised ones.
According to Vikas Sharma, COO (Smelters), Hindustan Zinc, there would have been some constraint in the Zinc supply chain a few years ago, but the same has been dealt with. He added that his company is in discussions with auto steel manufacturers like Tata, JSW and Posco towards the manufacture and supply of galvanised steel. Highlighting the manner in which the zinc coating sacrifices itself over the years, protecting the steel beneath even if the paint coating above is damaged, Vikas Sharma drew attention to the 9 million metric tonne production capacity through an open pit mine in Rajasthan. He also emphasised that those possessing the Continuous Galvanising Grade (CGG) for Automotive steels, are increasingly joining hands with apex bodies, like the International Zinc association, India Lead Zinc Development association (also key advisor to the Bureau of Indian Standards) with a common goal to modify the necessary code specifications.
With an average Indian car costing far more than an average European or American car due to taxes and duties, it is but natural for an Indian car buyer to ask for a car that lasts long enough if not longer than the cars found in advanced markets. Rather than waiting for the need to be mandated by the government or the judiciary, it may be well worth to expect Indian automotive manufacturers to equip cars that cost up to Rs10 lakh with zinc coated steel if they have been limiting the use of galvanised bodies only to those that are exported.