The switch was much publicised as it enabled producers to offer five to six year anti-corrosion warranties. But "there are signs that increased intensity of use of coated sheet in the car industry may reach saturation point beyond 2000," according to John Johnson, Research Manager steel at industry consultants CRU International.

James Christopher, Manager for Advanced Purchasing for Steel Worldwide General Motors, thought a ceiling would be reached by 2003/2004. At this point zinc consumption growth in the sector would have a more direct correlation with vehicle sales, he added.

General Motors, the world's number one car manufacturer, produces atotal of 8.5 million units per year. "The amount of galvanised sheet consumed at Volkswagen will depend on the level of group car sales," said the company's press department.

Most of VW's models are fully galvanised, with the exception of Minivans and Transporters, the old Beetle made in Mexico and older Golf models from South Africa. The company currently consumes about two million tonnes per year of galvanised steel sheet.

Galvanising so important to zinc
In 1998 galvanising accounted for nearly 50 per cent of total Western zinc demand, equating to around 3.7 million tonnes of metal.

This compares with 40 per cent in 1980. Most of zinc's other end-uses have largely shrunk or stagnated over a prolonged period. Zinc is used in various types and mixes of coatings in galvanising to make steel anti-corrosive.The continuous galvanising process, uses mainly the hot-dip, but also electrolytic methods for sheet in car body panels. "Very often the health of demand for galvanised steel sheet inautomobiles is taken as an indication of demand for galvanised sheet as a whole, but the automotive industry only takes around one-quarter of all zinc coated steel usage in Japan, the US and Western Europe," said Dr Tony Wall of the Zinc Development Association.

Construction is still the main end-use, accounting for about one-third. In the developing economies construction accounts for a greater proportion. The remainder is used in domestic appliances and other manufacturing industries.

Automobiles a major driving force
But its use in automobiles has been a major driving force behind zinc demand since the late 1980s. Anti-rust warranties continue to be used in Europe as a marketing tool and some carmakers have extended theirs to 11-12 years, while one or two are even offering lifetime guarantees.

Prior to the late 1980s only luxury models tended to benefit from zinc-coated bodies -- now they are the norm in the established producing countries.

According to an automotive spokesman for CORUS,the recently merged British Steel and Hoogovens, about 80 per cent of the average car body, known as the body-in-white (BIW) now consists of galvanised sheet, equating to 350 kg of steel and nine kg of zinc.

Others put the figure at 65-70 per cent, although the CORUS spokesman said the recent move by some producers towards 100 per cent galvanised bodies was pushing up the average, which he saw levelling out at about 85-90 per cent.Either way these figures compare favourably with CORUS' estimates of 50 percent coated sheet and 6kg of zinc in the average BIW in 1989 and just 15-20 percent or 2kg of zinc in 1984.

Volvo said its average BIW contains 85 per cent coated sheet, up 20 per cent from ten years earlier, while Fiat put its usage at 70 per cent. However, both said that a limit had been reached in the established producing countries.

Indeed, CRU's Johnson noted that there was a trend among US carmakers to stop using galvanised sheet for some parts, prompted by the realisation that their anti-rustqualities were unnecessary and adding needlessly to costs.All producers questioned agreed that the trend towards thinner zinc coatings, which until now has been more than offset by increased intensity of use, had run its course.

"We always try to optimise zinc consumption," the Volkswagen official said.

Developing countries may take up the reins
Consultants Brook Hunt thought that gains were still to be made in the automobile industry in developing economies in Latin America and Asia.In a recent report it pointed out that South Korea only uses galvanised steel in the BIW for models for the export market.

The Fiat spokesman also mooted that there may be potential for increased use in other parts of the world such as Brazil, China and India, where galvanised sheet use in the BIW was possibly as low as 20-30 per cent.

There is some scope for these countries to take up the reins to ensure continued strong zinc demand growth in the sector for years ahead. But the CORUS spokesman pointed out thatclimate conditions may detract from the need for galvanised sheet in some regions and that consumers may be less demanding.

Nevertheless, Brook Hunt expects galvanising to remain the fastest growing end-use between 1999 and 2010. "The main factors determining of growth (globally) will be automobile sales and construction activity".