Corrosion in automotive exhaust muffler

 The exhaust system of an automotive muffler has lots of prerequisite to accomplish. The foremost one is to reduce the noise level produced by the engine, adequate insertion loss, to access the waste gases out from the rear part of automobile system, to play down the reduction in engine performance, to have a satisfactory service life, back pressure, shape, style, and cost (1). A large variety of exhaust silencers having different design characteristics are available in an automotive market. They can be divided into various types like clamshell mufflers, wrapped mufflers, deep drawn mufflers, lock seam mufflers, welded mufflers, and so forth.

The main reason behind the premature muffler failure is because of the corrosion, fatigue or combination of the both. About 80% of the failure is due to corrosion and rest is by fatigue.

Some of the corrosion mechanisms affecting are as below:

(i) Internal corrosion due to acidic condensate.

(ii) External corrosion due to de-icing agents used on icy roads.

(iii) Material sensitization, especially on the hot spot (material temperatures up to 500º C for rear muffler and 600 ⁰C for front muffler.

(iv)Static loads due to heating and cooling cycles (low cycle fatigue).

(v) Vibrations from the engine (high cycle fatigue) (2).

Read more about corrosion in exhaust systems.