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Mechanical Engineering Courses

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Why engineers are not getting job offers?

Why engineers are not getting job offers?
Ever thought why engineers are not getting job offers? There are so many reasons behind every rejection. It takes time to learn skills which are required for successful job interviews. Every day I get so many messages from confused fresh graduates and engineers from all over the world who ask me to help then in getting a job. From these messages, it is very clear that they are trying hard to reach out to fellow engineers and they are putting their best efforts in finding a job. But all these efforts are in WRONG direction. Here I would like to share some common reasons of interview rejection and why engineers are not getting job offers.

I have gone through all these phases of life. It hard to understand all these reasons at start of career but over time you start to realize your mistakes. Here i would share my personal experiences.

Not preparing for interview
I have seen many candidates who do not prepare for interviews. Interview is just like an exam, if you do not prepare, you will fail. Preparation for an interview includes looking for answers to common engineering interview questions, revising basic concepts of mechanical engineering courses, and dressing up properly for interview.

General format of CV for all jobs
I have seen many candidates who have a general format of CV to apply for all type of jobs. A good engineer will always make changes to his CV according to job description.

Applying for too many posts in same organization/ company
Recently we are short listing engineering candidates for job interviews in my company. I have noticed so many candidates who applied for all positions with same CV. Is it logical applying for Manager Operations, Assistant manager operations, Assistant manager admin and Assistant operations at the same time? We rejected many candidates for this reason. Always be crystal clear about job position that you want to apply for.

Standing out too much
Only add relevant information to your CVs and portfolio. Adding too much colors, extra information and irrelevant skills will not make any difference.

What is in it for me?
Always ask questions from your interviewer. Try to learn what is in this job for you? What opportunities of learning do you have? Is it suitable for you? This will help you decide whether the company is right for you.

Interview answers
Always prepare for potential common interview questions. Many engineers do not get job offers because they do not give satisfactory answers to some tricky questions. During all interviews, some questions are of general nature while some questions are of technical nature.

Overconfidence
Overconfidence simply kills.

Lack of job information
Lack of job information and knowledge about possible job description gives a very bad impression about candidate. I once applied for a job position in a company dealing with water treatment plants. Reason for my rejection was that I could not explain how I would become a contributing member to this company because I was unaware of job description.

Non-confidence in employers’ recruitment procedure
Always show confidence in employers’ recruitment procedure. If they have called you for an interview, it means they are trying hard to do it on merit.

Always speak truth
Always speak truth. Those who are interviewing you, are experienced enough to catch false information through discussions.

Be yourself, be original
As simple as that: Be yourself, be original

Feel free to contact me if you have any further questions. I have learnt from my experiences how to get a job and how to successfully pass interviews. Contact me for any discussion about your career.

Engineering Materials - Introduction

The knowledge of engineering materials and their properties is of great importance for a design engineer. A design engineer must be familiar with the effects which the manufacturing processes and heat treatment have on the properties of the materials. The engineering materials are mainly classified as:

1. Metals and their alloys, such as iron, steel, copper, aluminum etc.
2. Non-metals, such as glass, rubber, plastic etc.


The metals may further be classified as:
(a) Ferrous metals; and (b) Non-ferrous metals.


The ferrous metals are those which have the iron as their main constituent, such as cast iron, wrought iron and steel.

The non-ferrous metals are those which have a metal other than iron as their main constituent, such as copper, aluminum, brass, tin, zinc etc.

The important mechanical properties of metals are as follows:

1. Strength. It is the ability of a material to resist the externally applied forces without breaking or yielding.
2. Stiffness. It is the, ability of a material to resist deformation under stress. The modulus of elasticity is the measure of stiffness.
3. Elasticity. It is the property of a material to regain its original shape after deformation when the external forces are removed. This property is desirable for materials used in tools and machines. It may be noted that steel is more elastic than rubber.
4. Plasticity. It is property of a material which retains the deformation produced under load permanently. This property of material is necessary for forgings, in stamping images on coins, and in ornamental work.
5. Ductility. It is property of a material enabling it to be drawn into wire with the application of a tensile force. A ductile material commonly used in engineering practice (in order of diminishing ductility) are mild steel, copper, aluminum, nickel, zinc, tin and lead.
6. Brittleness. It is the property of a material opposite to ductility. It is the property of breaking of a material with little permanent distortion. Cast iron is a brittle material.
7. Malleability. It is a special case of ductility which permits materials to be rolled or hammered into thin sheets. A malleable material should be plastic but it is not essential to be so strong. The malleable materials commonly used in engineering practice (in order of diminishing malleability) are lead, soft steel, wrought iron, copper and aluminum.
8. Toughness. It is the property of a material to resist fracture due to high impact loads like hammer blows. The toughness of a material decreases when it is heated. This property is desirable in parts subjected to shock and impact loads.
9. Resilience. It is property of a material to absorb energy and to resist shock and impact loads. It is measured by the amount of energy absorbed per unit volume within elastic limit. This property is essential for spring materials.
10. Creep. When a part is subjected to a constant stress at high temperature for a long period of time, it will undergo a slow and permanent deformation called creep. This property is considered in designing internal combustion engines, boilers and turbines.
11. Fatigue. When a material is subjected to repeated stresses, it fails at stresses below the yield point stresses. Such type of failure of a material is known as fatigue. The failure is caused by means of a progressive crack formation which are usually fine and microscopic size. This property is considered in designing shafts, connecting rods, springs, gears etc.
12. Hardness. It is a very important property of the metals and has a wide variety of meanings. It embraces many different properties such as resistance to wear, scratching, deformation and machinability etc. It also means the ability of a metal to cut another metal. The hardness is usually expressed in numbers which are dependent on the method of making the test.

Pig iron and its manufacturing

Pig iron is the crude form of iron and is used as a raw material for the production of various other ferrous metals, such as cast iron, wrought iron and steel. The pig iron is obtained by smelting iron ores in a blast furnace.

The iron ores are found in various forms as shown below:
Iron ores

The metallic contents of these iron ores are given in the following table:
Metallic content in iron ores
The haematite is widely used for the production of pig iron. Since pyrite contains only 30 to 40% iron, therefore it is not used for manufacturing pig iron.

The pig iron is obtained from the iron ores in the following steps:

1. Concentration. It is the process of removing the impurities like clay, sand etc. from the iron ore by washing with water.
2. Calcination or roasting. It is the process of expelling moisture, carbon dioxide, sulphur and arsenic from the iron ore by heating in shallow kilns.
3. Smelting. It is process of reducing the ore with carbon in the presence of a flux. The smelting is carried out in a large tower called blast furnace.

The blast furnace is a chimney like structure made of heavy steel plates lined inside with fire bricks to a thickness of 1.2 to 1.5 metres. It is about 30 metres high with a maximum internal diameter of 9 meters as its widest cross-section. The portion of the furnace above its widest cross-section is called stack. The top most portion of the stack is called throat through which the charge is fed into the furnace. The charge of the blast furnace consists of calcined ore (8 parts), coke (4 parts) and lime stone (1 part). The portion of the furnace, below its widest cross-section is known as bosh or the burning zone (or zone of fusion). The bosh is provided with holes for a number of water jacketed iron blowing pipes known as tuyers. The tuyers are 12 to 15 in number and are connected to bustle pipe surrounding the furnace.

In the lower part of the blast furnace (called zone of fusion), the temperature is 1200° C to 1300° C. In the middle part of the blast furnace (called zone of absorption), the temperature is 800° C to 1000°C. In the upper part of the blast furnace (called zone of reduction), the temperature is 400° C to 700° C.

At the bottom of the blast furnace, the molten iron sinks down while above this floats the fusible stage which protects the molten iron from oxidation. The molten iron thus produced is known as pig iron. The slag from the blast furnace consists of calcium, aluminum and ferrous silicates. It is used as a ballast for rail roads, mixed with tar for road making and in the cement manufacture.

The pig iron from the blast furnace contains 90 to 92% of iron. The various other elements present in pig iron are carbon (1 to 5%), silicon ( 1 to 2%), manganese (1 to 2%), sulphur and phosphorus (1 to 2%).

Note : Carbon plays an important role in iron. It exists in iron in two forms i.e. either in a free form (as graphite) or in a combined form (as cementite and pearlite). The presence of free carbon in iron imparts softness and a coarse crystalline structure to the metal, while the combined carbon makes the metal hard and gives a fine grained crystalline structure.

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