Stainless steel duplex stainless steels are achieved with an overall lower alloy content than similar-performing super-austenitic grades, making their use cost-effective for many applications. Duplex grades are characterized into groups based on their alloy content and corrosion resistance. Precipitation hardening stainless steels have corrosion resistance comparable to austenitic varieties, but can be precipitation hardened to even higher strengths than the other martensitic grades. The most common, 17-4PH, uses about 17% chromium and 4% nickel. The designation "CRES" is used in various industries to refer to corrosion-resistant steel. Most mentions of CRES refer to stainless steel, although the correspondence is not absolute, because
Stainless steel Cadillac Eldorado Brougham had a stainless steel roof. In 1981 and 1982, the DeLorean DMC-12 production automobile used Type-304 stainless steel body panels over a glass-reinforced plastic monocoque. Intercity buses made by Motor Coach Industries are partially made of stainless steel. The largest use of stainless steel in ICE-powered automobiles(ICE: internal combustion engines) is the exhaust line. Environment protection requirements of reducing pollution and noise for whole life of cars led to the use of ferritic grades typically AISI409/409Cb in North America, EN 1.4511 and 1.4512 in Europe. They are used for collector, tubing, muffler, catalytic converter, tailpipe. Heat resisting