Consumption of zinc has grown in India over time, helping sectors such as infrastructure, cosmetics, medicines, paints, rubber, surgical tools, plastics, textiles, soaps and batteries expand and grow. But corrosion losses impact India’s GDP considerably every year.
This can be checked if we promote galvanisation (cover metals with zinc) in construction. Western countries mandate the use of galvanising for steel structures used in building bridges, highways, airports, metro stations, railway stations, etc.
Zinc is the fourth most widely consumed metal in the world — after iron, aluminium and copper. Almost 50 per cent of the zinc mined across the world is used for galvanising, 17 per cent for zinc alloying, 17 per cent for brass and bronze making, 6 per cent in zinc semi-manufactures, 6 per cent in chemicals, and 4 per cent for other miscellaneous purposes.
India’s consumption of zinc is rising day by day as new sectors are being explored to take advantage of zinc. But its potential remains unrealised. .Coastal infrastructure
Use of Galvanised rebars in construction near coastal areas: Corrosion is one of the major reasons for deterioration of concrete structures built near coastal areas. Coastal salts coupled with humidity can corrode exposed metal surfaces and penetrate any opening in the building.
Coastal infrastructure within a range of 5 km is more prone to corrosions and becomes progressively worse closer to the marine source.
According to a study by the American Institute of Architects, it is essential to use hot dip galvanised steel to make such coastal infrastructure-decay resistant. Galvanised steel provides the much needed strength to rebars.Auto sector
Use of galvanised car bodies: Globally there has been a discrepancy in using galvanised car bodies. Indian car manufacturers use about 3 per cent galvanised steel for cars manufactured and sold in the domestic market. However, they over 70 per cent galvanised steel in exports to markets in Europe, Asia and Africa.
Indian consumers don’t demand galvanised steel due to lack of awareness on the long term benefits of galvanised vehicles.
Car makers in Europe, North America, Korea and Japan have been using galvanised steel for car body panels for decades and provide anti-corrosion and perforation warranties for a minimum of 10 years.
In India, the customers are advised to pay for extra coatings to protect the body of the car after purchase. More than 60 per cent of the cars in India have surface-rust which reduces steel strength and the life of the car, leading to safety hazard.
Steel has been used to make automobiles since the early 1900s but corrosion resistance features became standard in vehicles beginning in the early 1980s when Japanese cars gained entrance to the US market.
Globally, the annual consumption of zinc for auto-bodies today is roughly 120,000 tonnes. There is almost no galvanised steel on Chinese-made vehicles except for exports from China by Volkswagen, General Motors and others which also means that 20 million cars in China are not using galvanised steel.
Globally, galvanised steel car bodies have been shown to experience minimal corrosion attack which protects the structural integrity and safety of the vehicle, improves the resale value, provides consumer protection due to anticipated warranty improvements by the car companies, lowers maintenance costs of under-body and structural components due to the use of zinc coated steel, and saves consumers the costs of after-market anti-corrosion treatments and annual inspections.The railways
Corrosion of rails and fish plates: Galvanising of railway tracks would not only be a significant initiative towards safety of trains but would also give more life to the railway tracks. India’s rail tracks, spanning over 125,000 km, happen to be the world’s third largest. The annual loss due to pre-replacement of corroded rails is about ₹440 crore. Many accidents have been attributed to fish-plates. Not just the fish-plates, even the bolts need protection, protection from corrosion.
Experts have estimated losses of almost 4 per cent of GDP per year on account of corrosion which may be avoided if the railway tracks are galvanised. One of the significant aspects of railway track maintenance is the detection of corrosion and the replacement of corroded rails.
Corrosion reduces the life of rails to nearly half its expected life. The rails have a life of 800 gross million tonnes which works to approximately 12-13 years under normal traffic conditions in India. The shorter life of rails resulting from absence of galvanising increases track maintenance workload. Corrosion increases the pace of rails replacement and interferes with normal railway movement causing inconvenience to passengers and freight movers and revenue losses to the Railways.
According to a site inspection carried out by the Commissioner of Railway Safety (eastern circle) PK Acharya, rusted rails could have caused derailment near Kanpur that left 146 people dead and over 200 injured. The International Zinc Association advocates that Indian Railways require corrosion-free tracks in case India is considering Bullet Trains.Energy sector
Zinc powers the electricity distribution network: Since the advent of high voltage lines, hot-dip galvanised steel has been used in the electric utility market. Whether in a generation facility, substation, lattice tower, or renewable energy components, galvanised steel has been a backbone of any global economy.
According to a study by the American Iron and Steel Institute, close to 1 million steel distribution poles have been installed in the United States since 1998 and are being used by more than 600 US electric utilities. India might be having more poles but how many are galvanised is still to be assessed.
When India is looking ahead providing electricity in every village and progressively moving towards Smart Cities project, Digital India and Make in India, the very basis of infrastructure, the power transmission, needs to be protected for many years.
If these four sectors mandate to address the issue of corrosion and related safety, it would lead to not just efficiency and savings worth millions of dollars for the Indian economy, but also build long-lasting infrastructure.
The writer is CEO of Hindustan Zinc