A desire by car manufacturers to reduce corrosion in critical fuel system components has led to a sharp increase in the replacement of carbon steel with stainless steel components. In 2004 Associated Tube Industries (Canada) used 4,300 tonnes of S30400 and S30403 for automotive applications, compared to 2,400 tonnes in 2002. The fuel filler tube, which extends down into the gas tank, has traditionally been fabricated from carbon steel, then coated to give it some corrosion-resistance. But in 2002, Associated Tube began receiving orders to fabricate filler tubes from S30403. Currently about 128,400 units are being produced every month (45 tonnes of S30403), and by the third quarter of 2005, this rate will increase to about 192,500 units, (68 tonnes of S30403). The fuel filler tubes vary in length from 23cm to 114cm and are made in two outside diameters: of 2.7cm and 2.6cm. They are roll-formed and seam-welded from flat coil stock. For the engine end of fuel systems, Associated Tube fabricates five different fuel rail tube designs from S30403; it then sells these to a fabricator of completed systems that deliver fuel to engine combustion chambers. Flat coil stock 0.889mm thick is roll-formed into round tubes ranging in length from 30cm to 46cm, then seam-welded and further formed to give them square, trapezoidal and other shapes in cross-section.
