Grace Mission English Medium Higher Secondary School Interview Questions and Answers

Factors affecting mechanical properties like tensile in grey iron include composition, microstructure, heat treatment, and casting process.

• Composition of grey iron, including the amount of carbon and silicon, affects its mechanical properties.

• Microstructure, such as graphite morphology and matrix structure, plays a significant role in determining tensile strength.

• Heat treatment can alter the mechanical properties of grey iron by changing its microstructure.

• Casting process par...read more

Changing elements like Si, Carbon, Cr in grey iron or sg iron can significantly impact mechanical properties.

• Increasing Silicon content can improve fluidity and machinability but decrease strength

• Increasing Carbon content can increase hardness and wear resistance

• Adding Chromium can improve corrosion resistance and strength

• Changing elements must be carefully balanced to achieve desired mechanical properties

Nitrogen pinholes are typically smaller and more numerous compared to hydrogen pinholes.

• Nitrogen pinholes are usually smaller in size and more numerous than hydrogen pinholes.

• Hydrogen pinholes are larger in size and less frequent than nitrogen pinholes.

• Nitrogen pinholes are commonly found in aluminum castings, while hydrogen pinholes are more common in steel castings.

Process parameters such as temperature, pressure, and time can significantly impact the mechanical properties of a material.

• Temperature: Higher temperatures can increase ductility but decrease strength.

• Pressure: Higher pressure can improve density and strength.

• Time: Longer processing times can lead to better homogeneity and mechanical properties.

• Example: Heat treatment of steel involves specific temperature and time parameters to achieve desired mechanical properties.

Carbon equivalent is determined by calculating the combined effect of different alloying elements on the hardenability of steel.

• Calculate the carbon equivalent using the formula: CE = C + (Mn/6) + (Cr + Mo + V)/5 + (Ni + Cu)/15

• Higher carbon equivalent indicates higher hardenability and potential for cracking during welding

• Lower carbon equivalent is preferred for better weldability and toughness

• Carbon equivalent is important in determining the heat treatment process for steel

• E...read more