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PRESENTED BY :

IRWIN MAULANA3334090293

METALLURGICAL DEPARTMENT

“Corrosion in the Muffler”

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Outline

Corrosion in the Muffler

1. Irwin Maulana

2. 3334090293

3. Metallurgical Engineering

1. Introduction2. Kinds of corrosion3. Prevention 4. Advantages and

Disadvantage5. Refferences

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Introduction

An automotive exhaust system consists of the following seven components from the engine side:

a. an exhaust manifold, b. a front pipe, c. a flexible pipe, d. a catalytic converter, e. a center pipe, f. a main muffler, and g. a tail end pipe.

Muffler ????

Muffler - A device with baffled passages through which exhaust gases are channeled in order to muffle engine sound

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Muffler is a part of exhaust system that

have many functions, and made from

metal.

THE MAIN MUFFLER ABSORBS AND REDUCES

THE NOISE OF THE EXHAUST GAS, AND IS

COMPOSED OF AN OUTER SHELL,

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The principal properties required

1. high-temperatures strength,2. thermal fatigue properties, 3. oxidation resistance and salt corrosion

resistance at high temperatures, and 4. the same required for the components

away from the engine (cold end) is corrosion resistance to salt damage and exhaust gas condensate.

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Ferritic Stainless Steels ( steels in the 400 series contains 10.5% to 20% chromium )

Good for corrosion resistance and resistance to scaling at elevated temperatures

nonhardenable by heat treating and are always magnetic.

is used in applications where resistance to corrosion is important, such as automotive emission control exhaust systems.

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Kinds of corrosion

Condensate Pitting CorrosionExterior Salt PittingCrevice corrosionGalvanic corrosionOxidationHot Salt Attack

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Condensate Pitting Corrosion

The main muffler is heated by the exhaust gas to about 400°C, at the highest, during a long-distance run and the condensation of water does not take place but in the case of a short-distance run, the temperature does not go up and condensation occurs inside it.

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1. By the presence of the condensate, a very corrosive humid environment is formed inside a muffler.

2. On the other hand, the outer surface of a muffler is exposed to a salt corrosion environment of the deicing salt. Chloride-containing de-icing salts on the roads in colder countries greatly increases the rate of corrosion on the exterior surfaces.

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Prevention

Material selection

Coating (Vitreous Enamel)

Using crystalline of zeolite and activated alumina

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Advantages and Disadvantage

Advantages

1) Give an arthistic value

Disadvantages

1) Decrease the life time

2) Of all automobile exhaust failures, about 80% are caused by corrosion

3) Cause a noise problem

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Refferences

ASM Handbook_ Volume 13C. Corrosion: Environments and Industries

D.C. Oliver and M. Sephton , External corrosion resistance of steel and ferritic stainless steel exhaust systems

Fethke, et.al. Methods for Retarding the Corrosion in Mufflers

J.H. Potgieter, M. Sephton and Z.W. Nkosi, Corrosion of hot end automotive exhaust components

Yoshiharu INOUE Masao KIKUCHI. Present and Future Trends of Stainless Steel for Automotive Exhaust System.

www.aksteel.com

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...THANK YOU...