ANNA UNIVERSITY , AUTOMATIVE, MATERIALS AND METALLURGY

 ANNA UNIVERSITY , AUTOMATIVE, MATERIALS  AND  METALLURGY

  B.E. AUTOMOBILE  ENGINEERING , Semester

 

PART – A  (10 x 2  =  20   Marks)

 

 1With an example explain stress concentration.

2Under what conditions Martensite forms.

3.What is an eutectoid reaction?  Give examples.

4.Generally where do fatigue cracks originate? Why?

5.State the difference between trans granular and inter granular fracture.

7.How can the machinability of steel improved?

8.Give the composition of any modern material used for the making the automobile cylinder block.

9.State the chemical composition of any one material each used for making the automobile connecting rod and the crankshaft.

10.Explain briefly the procedure involved in anodizing.

11.In normalizing of steels, give the heating range for hypo and hyper eutectoid steels.

 

PART – B  (5 x 16 = 80  Marks)

 

11.i) Explain the Griffith’s theory of fracture and derive an equation for stress necessary to cause brittle fracture.                                                                              

 ii) What is creep?  Draw a typical creep curve and explain the three stages of creep.

OR

12.a)i)  Draw the Iron Carbon diagram and show the important phases, reactions, temperatures.                                                                                                        

 ii) Illustrate the crystal structure of martensite and state its properties.                   

(OR)

12.b)i)  With figures explain the mechanism of ductile fracture in a pearlitic steels.     

       ii)  Discuss various strengthening mechanisms of polycrystalline materials.          

 

13.a)i)  Discuss the mechanism of crack initiation and growth in fatigue.                       

 ii)  Explain the effect of the following on fatigue                                                    

–  stress concentration

–  size of specimen

–  surface residual stress

–  mean stress

 (OR)

 

13.b) Write short notes on the following :                                                                  

–  S-N diagram in fatigue

–  Machinability of cast iron, mild steel and high speed steel

–  High temperature materials

–  Materials for cryogenic applications.

 

14.a)i) Discuss the properties and automotive applications of Nickel Steels, Chromium Steels and Manganese Steels.                                                                              

 ii)   Discuss the applications of polymers in Automobiles.                                        

(OR)

 

14.b)i)  Explain the merits of fibre reinforced plastics and their automotive applications.    

                                               

ii)  List the various types of casting defects and state the reasons for these defects and the preventive measures to avoid these defects.                                                 

 

15.a)i)  Explain the procedure involved in any three types of annealing and state their applications.                                                                                                        

ii)  Illustrate the isothermal transformation diagram for a eutectoid steel and show all the important features.                                                                              

                                                    (OR)

 

15.b)i)  Explain the principles, procedure and applications of Induction Hardening.     

       ii)  Discuss the principles, procedure and applications of pack and gas carburizing.

 

 

 

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