Abstract: The invention relates to an exhaust muffler for a motor vehicle, consisting of an external casing (1), an internal casing (2) and a central part (3) consisting of perforated tubing (4) and transverse partitions (5) assembled together to form a chicane, called the insides. The central part (3) is made of an enameled steel, the steel having the following composition in thousandths of a percent by weight:carbon between 0 and 100manganese between 0 and 500phosphorus between 0 and 30sulfur between 0 and 40aluminum between 0 and 60titanium between 0 and 200copper between 0 and 60nitrogen between 0 and 15,the remainder being iron and residual impurities, said steel being obtained by hot rolling at a final rolling temperature exceeding the Ar.sub.3 point to obtain a strip, which is coiled at a temperature higher than 600 degrees Celsius and, after cold rolling, is subjected to a recrystallization annealing.