Basic Mechanical engineerning

Daily Current Affairs – 26th January, 2017

Growing Chinese Presence in South Asia Introduction Growing Chinese influence in South Asia has been very evident in the past few years. When Sri Lanka decided to develop the Hambantota port and areas around it, the Sri Lankan government was not very keen on taking assistance [...]

Explain the effect of alloying various elements on properties of steel.

Ans·. The effects of various alloying elements are as follows (i) Nickel- (a) Nickel increases hardness, toughness and impact strength at low temperature. (b) Improves response to heat treatment especially in large sections. (c) Improves elasticity, resistance to fatigue and corrosion. (ii) Chromium - (a) It forms a complex series [...]

Write short note on – Alloy steels. Or What are alloy steels ? Why is alloying done ?

Ans. An alloy steel may be defined as steel to which elements other than carbon are added in sufficient amount to produce improvements in steel. Commonly used alloy elements are nickel. chromium, manganese, silicon, molybdenum, vanadium, phosphorus, tungsten, titanium, copper, zirconium, cobalt and aluminium. These elements may be [...]

Describe the various mechanical properties of materials in short. Or Write about the various mechanical properties of metals.

Ans. The material properties which are associated with the ability of the material to resist mechanical forces and loads are known as mechanical properties. The mechanical properties are a measure of the strength and lasting characteristics of a material in service. Some important mechanical properties are described below [...]

Discuss the iron carbon diagram and various allotropies of steel. Or Draw a neat sketch of iron carbon equilibrium diagram and explain the following reactions- (i) eutectic reaction (ii) eutectoid reaction (iii) peritectic reaction.

Ans. Fig· 1.1 shows an Iron-carbon equilibrium diagram since any iron carbon alloy in the molten state may be considered as a solution of iron carbide Fe3C in iron. Therefore, it is also called as iron-iron carbide equilibrium diagram. An equilibrium phase or constitutional diagram is a [...]

What are the composition, properties and uses of high speed steel ? State its various types.

Ans. As the name indicates, high speed steel is used for high speed cutting tools. These steels can be divided into two groups depending upon the principal alloying element. The first group is called tungsten high speed steels and is designated by T-series. Steels of this group [...]

Give the compositions, properties and uses of mild and high carbon steels.

Ans- (i) mild steel-  mild steel contains 0.05 to 0.3 carbon. It is further classified into three types- (a) Dead mild steel       -     0.05-0.15% c (b) Mild steel                -     0.15 - 0.2% c (c) Mild steel                -      0.2 _0 3% Properties – Various properties of mild  steel are [...]