International Zinc Association claims that despite any technical hurdles, some OEMs in India choose to cut costs and skip anti-corrosion treatment in vehicle bodies. However, export models are treated differently with an anti-corrosion galvanisation process that covers up to 70% of the vehicle's body shell till the window line.
21 Sep 2019 | 32119 Views | By Mayank Dhingra
That India is a price-sensitive market is well known. When it comes to the world of automobiles, OEMs have always been seen resorting to unique VA/VE methodologies (Value Engineering, Value Analysis or Value Management) to drive cost optimisation and keep the final sticker price of their products competitive.
While feature ...
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That India is a price-sensitive market is well known. When it comes to the world of automobiles, OEMs have always been seen resorting to unique VA/VE methodologies (Value Engineering, Value Analysis or Value Management) to drive cost optimisation and keep the final sticker price of their products competitive.
While feature reductions in the form of no power windows, electronically adjustable ORVMs, height-adjustable seats or even the very basic safety-critical option of adjustable headrests are being prominently implemented by OEMs even in the new models being introduced in the present day, there lies a fundamental question as to how safe the body shell of the car itself is.
With vehicle crash test norms soon to be mandatory for each and every car model getting sold in India from October 2019, a few carmakers have already announced plans to discontinue some of their best-sellers, which are beyond the scope of structural improvement or would have required huge investments in doing so, making the business case unviable.
Different standards for domestic market and exports?
Now IZA (International Zinc Association) has revealed a shocking statistic – the use of galvanised steel or zinc-coated steel is as low as 17 percent (or less) for passenger cars being produced by some reputable global OEMs for the Indian market, making them prone to corrosion.
The irony, however, is that the same automakers, says IZA, go all out and treat their made-in-India export models and process them through an anti-corrosion galvanisation process that covers up to 70 percent of the vehicle's body shell till the window-line.
In both cases, however, the current usage of galvanised steel in vehicles produced in India is far lower than that of North America and Europe, where vehicle manufacturers use galvanised steel in over 90 percent of the vehicle body even including the pillars, barring just the roof, which is a non-critical area when it comes to the topic of corrosion.
Galvanisation is when a protective zinc coating is applied to steel or iron, to prevent rusting. The most common method is hot-dip galvanising. This is when metal parts are fully submerged in a bath of molten zinc.
A lack of awareness among Indian consumers, says the global metal body, and no regulation from the government mandating use of galvanised steel are cited as the main reasons enabling OEMs to continue with this practice.
"There are no technical hurdles as such. Auto companies already have the BIW pre-treatment setups which are being used to galvanise the export models being built in India. We are only talking about a mere 0.01 percent of the additional cost of the vehicle to include galvanisation and offer improved structural safety and longevity to the vehicle," says Kenneth M de Souza, Technical Expert, Galvanising and Prepaint, IZA.
As per an independent study conducted by IIT Mumbai, on behalf of the IZA, car corrosion surveys in Mumbai and Chennai (two coastal areas) confirm visibility of corrosion in areas such as door sill plates and front cross-members of vehicles after a duration of five years of being on the road.
"Galvanisation first started in the automotive industry in the 1980s in the US after multiple class action lawsuits were filed against Ford Motor Company. While people have always related automobile corrosion to the de-icing salt put to use in the North American region, that's not true. We have found similar rusting issues in our surveys conducted in India as well," says de Souza.
"There is a secondary market in India for upper and under-body coatings, which are not done with the best levels of workmanship and also don't offer durability that the paint systems inside a car company can offer," he adds.
Zinc offers crucial protection against inclement weather and pollution, and also prevents loss of metal weight, or, in other words, corrosion to metal surfaces over prolonged exposure. Hence, galvanisation, which is the process of coating iron or steel with zinc, has found widespread application globally as a means of preserving infrastructure such as railway tracks, bridges, airports as well as vehicles.
According to Sunil Duggal, CEO, Hindustan Zinc and vice-chairman, IZA, "India loses around 3-4 percent of GDP annually on account of corrosion losses. Western countries, which are far ahead of us in terms of infrastructure, have mandated the use of galvanised steel structures in bridges, highways, public utilities, airports, metro stations and railway stations, and are thus able to preserve long-lasting and robust structures."
Zinc is a US$ 40 billion per year market and is the fourth-largest used metal worldwide behind iron, aluminium and copper. However, the per capita consumption of zinc in India is far behind at 0.6kg to the world average of 2kg. Penetration of galvanised sheet metal in India lies at 8 percent with respect to 19 percent in the US and 18 percent in Europe. While the transportation sector contributes 21 percent to the total galvanised steel consumption in advanced markets, in India it stands at 13 percent.
Lightweighting promoting galvanisation
Nonetheless, some automobile manufacturers such as Mahindra & Mahindra and Maruti Suzuki India have recognised the importance of galvanisation, given the increased use of High Strength Steel and Ultra High Strength Steel in their cars, which offer more strength but are thinner and lighter at the same time. "So, it becomes all the more important to protect this metal which is now thinner and could easily be affected by corrosion," adds de Souza.
While both the aforementioned companies are believed to have increased the portion of galvanisation in their domestic as well as export models being produced in India, Mahindra & Mahindra, especially has started using a process called 'galvanneal', which is a variation of galvanisation and includes galvanising followed by annealing process of sheet steel to provide a slightly harder and more brittle coating to the surface. The company is doing this for all its domestic and export models at its Nashik plant, according to de Souza.