Stainless Steel and its type

 

Stainless Steel is defined as that steel which when correctly heat treated and finished, resists oxidation and corrosive attack from most-corrosive media. The different types of stainless steels are as follows:

1. Martensitic stainless steel. The chromium steels containing 12 to 14% chromium and 0.12 to 0.35% carbon is called martensitic stainless steel, as they possess martensitic structure. These steels are magnetic and may be hardened by suitable heat treatment and the hardness obtainable depends upon the carbon content. These steels can be easily welded and machined.

2. Ferritic stainless steel. The steels containing greater amount of chromium (from 16 to 18%) and about 0.12% carbon are called ferritic stainless steels. These steels have better corrosion resistant property than martensitic stainless steels.

3. Austenitic stainless steel. The steel containing high content of both chromium and nickel are called austenitic stainless steels. The most widely used steel contains 18% chromium and 8% nickel. Such a steel is commonly known as 18/8 steel. These steels are non-magnetic and possesses greatest resistance to corrosion and good mechanical properties at elevated temperature.

governing of I.C. engines by moses dhilipkumar

 The process of providing any arrangement, which will keep the engine speed constant (according to the changing load conditions) is known as governing of I.C. engines. Though there are many methods for the governing of I.C. engines, yet the following are important :

1. Hit and miss governing. In this system of governing, whenever the engine starts running at higher speed (due to decreased load), some explosions are omitted or missed. This is done with the help of a centrifugal governor. This method of governing is widely used for I. C. engines of smaller capacity or gas engines.

2. Qualitative governing. In this system of governing, a control valve is fitted in the fuel delivery pipe, which controls the quantity of fuel to be mixed in the charge. The movement of control valve is regulated by the centrifugal governor through rack and pinion arrangement.

3. Quantitative governing. In this system of goverliing, the quality of charge (i.e. air-fuel ratio of the mixture) is kept constant. But the quantity of mixture supplied to the engine cylinder is  varied by means of a throttle valve which is regulated by the centrifugal governor through rack and pinion arrangement.

4. Combination system of governing. In this system of governing, the qualitative and quantitative methods of governing are combined together.

Black exhaust smoke

 BLACK EXHAUST SMOKE

Diagnosis: Not normal

Black exhaust smoke can appear when the vehicle is burning too much fuel. This could be caused by a clogged air filter, malfunctioning fuel injection system, a blocked manifold, or a variety of other issues. A clogged air filter won't hurt your gas mileage thanks to today’s automotive technology, says Consumer Reports, but you’ll pay for it with poor performance. Have your vehicle checked out by a technician to see why your vehicle is burning more fuel than usual.

knocking in I.C. Engines

 

👆

Detonation or knocking in I.C. Engines – The loud pulsating noise heard within the engine cylinder of an I.C. engine is known as detonation (also called knocking or inking). It is caused due to the propagation of a high speed pressure wave created by the auto-ignition of end portion of unburnt fuel. The blow of this pressure wave may be of sufficient strength to break the piston. Thus, the detonation is harmful to the engine and must be avoided. The following are certain factors which causes detonation:

1.    The shape of the combustion chamber,

2.    The relative position of the sparking plugs in case of petrol engines,

3.    The chemical nature of the fuel,

4.    The initial temperature and pressure of the fuel, and

5.    The rate of combustion of that portion of the fuel which is the first to ignite. This portion of the fuel in heating up, compresses the remaining unburnt fuel, thus producing the conditions for auto-ignition to occur.

The detonation in petrol engines can be suppressed or reduced by the addition of a small amount of lead ethide or ethyl fluid to the fuel. This is called doping.

The following are the chief effects due to detonation:

1.    A loud pulsating noise which may be accompanied by a vibration of the engine.

2.    An increase in the heat lost to the surface of the combustion chamber.

3.    An increase in carbon deposits.

Fluid coupling and its UN known information

  Fluid coupling and its  UN known information

 

It is a device for transmitting rotation between shafts by means of the acceleration and deceleration of a hydraulic fluid (such as oil). Also known as hydraulic coupling. Structurally, a fluid coupling consists of an impeller on the input or driving shaft and a runner on the output or driven shaft. The two contain the fluid. Impeller and runner are bladed rotors, the impeller acting as a pump and the runner reacting as a turbine. Basically, the impeller accelerates the fluid from near its axis, at which the tangential component of absolute velocity is low, to near its periphery, at which the tangential component of absolute velocity is high. This increase in velocity represents an increase in kinetic energy. The fluid mass emerges at high velocity from the impeller, impinges on the runner blades, gives up its energy, and leaves the runner at low velocity.

Hydraulic fluid couplings transfer rotational force from a transmitting axis to a receiving axis. The coupling consists of two toroids — doughnut-shaped objects — in a sealed container of hydraulic fluid. One toroid is attached to the driving shaft and spins with the rotational force. The spinning toroid moves the hydraulic fluid around the receiving toroid. The movement of the fluid turns the receiving toroid and thus turns the connected shaft.

Although fluid couplings use hydraulic fluid within their construction, the mechanism loses a portion of its force to friction and results in the creation of heat. No fluid coupling can run at 100 percent efficiency. Excessive heat production from poorly maintained couplings can result in damage to the coupling and surrounding systems.

A fluid coupling is a hydrodynamic device used to transmit rotating mechanical power. It has been used in automobile transmissions as an alternative to a mechanical clutch. It also has widespread application in marine and industrial machine drives, where variable speed operation and/or controlled start-up without shock loading of the power transmission system is essential.

What become your kid ????

 A company ...

 Announced that it needed people for the job,

 Accordingly_

 A lot of people came to the interview.

 Everyone was seated in a hall ...

 Question papers for all,

 Farewell letter was also given.

 Now the company manager spoke,

 '... there are ten questions in this quiz.'

 'You will be allotted five minutes.

 By then you have to answer these questions. '

 'Qualified persons will be selected and given jobs' ....

 Five minutes started ..

 Everyone wrote fast answer that time is limited.

 When the time is up ...

 The manager who bought the farewell paper for everyone said that you gave less time to each one when buying the farewell and we could not write the answer to all the questions except we were able to answer five questions and seven questions.

 Only two of them gave the blank sheet to the manager that he had not written any reply to.

 after that,

 Said the company manager.

 '' Only two people who did not write the answer sheet are eligible to work in this company.

 Others can go home. "

 The same surprise for everyone,

 Everyone asked the company manager to join one.

 _You say we do not work for answering questions correctly.

 How did you get the job done to only those two who did not answer any questions?

 (This is the question that arises in us at this point. Is there a job for those who have answered and those who have not?)

 To which the manager said,

 "Everybody read that tenth question,"

 Everyone who read it went home without being able to speak,

 This is the tenth question.

 # 10) This means that you do not have to answer any of the above questions.

 This is not something to be laughed at.

 Something we all need to think about,

 Wouldn't you have gotten the job if you had set aside two minutes and read the whole question paper?

 For Thought #:

 Except that in this modern age we have to buy a lot of marks by telling children to read step by step,

 No one thinks our children should grow up good and smart ...

Types of mechanical forces

 

A force exerted on a body can cause a change in either the shape or the motion of the body. The unit of force in SI system is the newton (N) and CGS system is dyne. No solid body is perfectly rigid and when forces are applied to it, changes in dimensions occur. Such changes are not always perceptible to the human eye since they are negligible. For example, the span of a bridge will sag under the weight of a vehicle and a spanner will bend slightly when tightening a nut. It is important for civil engineers and designers to appreciate the effects of forces on materials, together with their mechanical properties of materials.

There are three main types of mechanical forces that can act on a body. They are:

1.      Tensile force

2.      Compressive force and

3.      Shear force

1. Tensile force

Tensile force that tends to stretch a material, as shown in the figure 1 below.

Figure 1: Tensile force

For example,

1.      Rubber bands, when stretched, are in tension.

2.      The rope or cable of a crane carrying a load is in tension.

3.      When a nut is tightened, a bolt is under tension.

A tensile force will increases the length of the material on which it acts.

2. Compressive force

Compressive force that tends to squeeze or crush a material, as shown in the figure below.

For example,

A pillar supporting a bridge is in compression.

1. The sole of a shoe is in compression.
2. The jib of a crane is in compression.
3. A compressive force will decrease the length of the material on which it acts.

3. Shear force

Shear force that tends to slide one face of the material over an adjacent face.

For example,

1. A rivet holding two plates together is in shear if a tensile force is applied between the plates as shown in Figure
2. A guillotine cutting sheet metal, or garden shears, each provide a shear force.
3. A horizontal beam is subject to shear force.
4. Transmission joints on cars are subject to shear forces.

A shear force can cause a material to bend, slide or twist.

What is Cetane Number ???? Awesome information

 What is Cetane Number? How rating of fuels used in C. I. Engines (Compression Ignition Engines) is done using Cetane number and other parameters?

The knocking tendency is also found in compression ignition (C. I.) engines with an effect similar to that of S. I. engines, but it is due to a different phenomenon. The knock in C. I. engines is due to sudden ignition and abnormally rapid combustion of accumulated fuel in the combustion chamber. Such a situation occurs because of an ignition lag in the combustion of the fuel between the time of injection and the actual burning.

The property of ignition lag is generally measured in terms of cetane number. It is defined as the percentage, by volume, of cetane in a mixture of cetane and alpha-methyl-naphthalene that produces the same ignition lag as the fuel being tested, in the same engine and under the same operating conditions. For example, a fuel of cetane number 50 has the same ignition quality as a mixture of 50 percent cetane and 50 percent alpha-methyl-naphthalene.

The cetane which is a straight chain paraffin with good ignition quality is assigned a cetane number of 100 and alpha methyl-naphthalene which is a hydrocarbon with poor ignition quality, is assigned a zero cetane number.

Notes:                                                                             

1.    The knocking in C. I. engines may be controlled by decreasing ignition lag. The shorter the ignition lag, the lesser is the tendency to knock.

2.    The cetane number of diesel oil, generally available, is 40 to 55.

Eating Rice is health

 * Some  doctors have been deceived into believing that eating rice will lead to diabetes. *

* In fact, eating rice will cure diseases *

* What are the benefits of any rice!? *

1. * Black gourd rice *

Rice eaten by kings. Cancer does not come. Insulin secretion.

2. * Groom samba rice *:

Nerve, body strong. Masculinity may.

3. * Poongar rice *:

Is childbirth. Breastfeeding.

4. * Wild rice *:

Corrects diabetes, constipation, cancer.

5. * Conceived rice *:

By the way, things like constipation are okay.

6. * Chronological rice *:

After the Buddha had eaten. Brain, nerve, blood, kidney are OK.

7. * Bamboo rice *:

Arthritis and knee pain are okay.

8. * Sixtieth Curry Rice *:

The bone is right.

9. * Iluppaippusambar rice *:

Good for stroke. Foot pain is OK.

10. * Thangachamba rice *:

The tooth, the heart is strong.

11. * Black rice *:

Restores lost power. Cure deadly diseases.

12. * Garuda samba rice *:

Blood, body and mind are cleansed.

13. * Car Rice *:

Skin disease is OK.

14. * Umbrella Banana Rice *:

The bowel is cleansed.

15. * Kichili Samba Rice *:

High in iron and calcium.

16. * Blue samba rice *:

Anemia will go away.

17. * Cumin samba rice *:

Giving beauty. The resistance might.

18. * Pure Coriander Rice *:

The internal organs are strong.

19. * Pitted rice *:

Breastfeeding.

20. * Salem Sanna Rice *:

Strengthens muscle, nerve, and bone.

21. * Picini rice *:

Menstruation and pelvic pain are okay.

22. * Zucchini Rice *:

Pillow body may be leopard beauty.

23. * Walon Samba Rice *:

Is childbirth. Gather beauty for women and slim down in between. The hips are strong. Men may have sperm power.

24. * Watan Samba Rice *:

Quiet sleep will come

25. * Department *

Gives strength to the body. Increases strength. Strengthens the body.

26. * Until *

Reduce obesity. Prevent constipation. Reduce the amount of sugar

27. * Dye *

Relieves fever and dryness. Eliminates impotence. Controls stomach related diseases.

28. * Horsepower *

Muscles and bones become stronger.

39. * Hand stabbing *

Provides essential nutrients to the body. Prevents cancer. Prevents kidney stones. Helps to reduce body weight.

30. * Red wild rice *

Lowers cholesterol in the blood. Helps to control sugar levels.

31. * Red rice *

Minerals help greatly in the growth of hair, teeth, nails, muscles and bones.

32. * Dwarf rice *

Blood cleanses the body. Skin disease is cured.

Thanks.

Enthalpy

 Enthalpy is the measure of heat energy in the air due to sensible heat or latent heat. Sensible heat is the heat (energy) in the air due to the temperature of the air and the latent heat is the heat (energy) in the air due to the moisture of the air. The sum of the latent energy and the sensible energy is called the air enthalpy. Enthalpy is expressed in Btu per pound of dry air (Btu/lb of dry air) or kilojoules per kilogram (kJ/kg).

Enthalpy is useful in air heating and cooling applications. Air with same amount of energy may either be dry hot air (high sensible heat) or cool moist air (high latent heat)

The enthalpy scale is located above the saturation, upper boundary of the chart. Lines of constant enthalpy run diagonally downward from left to right across the chart; follow almost exactly the line of constant wet bulb temperature.

When a process takes place at constant pressure, the heat absorbed or released is equal to the Enthalpy change. Enthalpy is sometimes known as “heat content”, but “enthalpy” is an interesting and unusual word, so most people like to use it. Etymologically, the word “entropy” is derived from the Greek, meaning “turning” and “enthalpy” is derived from the Greek meaning “warming”. As for pronunciation, Entropy is usually stressed on its first syllable, while enthalpy is usually stressed on the second.

Enthalpy(H) is the sum of the internal energy(U) and the product of pressure(P) and volume(V).

Enthalpy H can be written as,

H = U + pV

Where, H = Enthalpy of the system

U = Internal energy of the system

p = Pressure of the system

V = Volume of the system

Enthalpy is not measured directly, however, the change in enthalpy (ΔH) is measured, which is the heat added or lost by the system. It is entirely dependent on the state functions T, p and U.

Enthalpy can also be written as

ΔH=ΔU+ΔPV

At constant temperature, for the process heat flow(q) is equal to the change in enthalpy, this is represented as

ΔH=q

Enthalpy Units

The Enthalpy is expressed as,

H = Energy/Mass

Any physical quantity can be represented by dimensions. The arbitrary magnitudes allocated to the dimensions are called units. There are two types of dimensions namely primary or fundamental and secondary or derived dimensions.

Primary dimensions are: mass, m; length, L; time, t; temperature, T

Secondary dimensions are the ones that can be derived from primary dimensions such as velocity(m/s2 ), pressure (Pa = kg/m.s2 ).

There are two unit systems currently available SI (International System) and USCS (United States Customary System) or English system. We, however, will use SI units exclusively in this course. The SI units are based on the decimal relationship between units.

MAJOR CAUSES OF ENGINE BREAKDOWN OR SUDDEN STOPPING.

 MAJOR CAUSES OF ENGINE BREAKDOWN OR SUDDEN STOPPING.

1) Overheated engine 

2) Chocked catalytic converter 

3) Electrical issues in the Ignition System.

4) Inadequate Transmission Fluid leading to increased friction in the gearbox.

5) Loose engine Bolts. 

CAUSES OF ENGINE BREAKDOWN.

- Engine overheating.

As the fuel burns the Chemical Energy is changed to Heat Energy. The engine further changes the Heat Energy to Mechanical Energy which propels the car.

If this Heat in the Engine bay goes beyond the normal range, the pistons and the engine start expanding. Engine expansion compresses the cylinder decreaing their diameter and hence icreasing the friction between the the piston and the Cylinder Walls as the piston moves up and down.

Eventually if the temperature keeps rising the piston is tightly held by the cylinder walls and its unable to move again and this  leads to a sudden engine stop.

CAUSES OF ENGINE OVERHEATING.

1) Defective Radiator Cap.

2) Leakage in the cooling system 

3) Condensed Engine coolant 

4) Blockage to coolant circulation delivery galleries.

5) Low Engine Oil level.

6) Broken or Defective Water Pump. 

Follow For More Educative Lectures.

Thank You.

Super alloy and its amazing components

 Composition: OF super alloy

These alloys are referred to as iron-base, cobalt-base or nickel-base super alloys. They contain nickel, chromium, cobalt and molybdenum as major alloying elements; Most super alloys have a maximum service temperature of about 1000°C for non-load bearing components.

Iron base super alloys generally contain composition of 32% to 67% iron, from 15% to 22% chromium and from 9% to 38% nickel.

Cobalt-base super alloys generally contain composition of 35% to 65% cobalt, 19% to 30% chromium and up to 35% nickel. Cobalt (Co) is white-colored metal that resembles nickel. These super alloys are not as strong as nickel-base super alloys in this they retain their strength at higher temperatures.

Nickel-base super alloys are the most common of the super alloys and they are available in a variety of compositions. The composition of nickel is from 38% to 76%; they also contain up to 27% chromium and 20% cobalt. Common alloys in this group are the Hastelloy, Inconel, Nimonic, Rene, Udimet, Astroloy and Waspaloy series.

 

What Mechanical Engineers Do

 What Mechanical Engineers Do

Mechanical engineers research, design, build, configure and test mechanical and thermal sensors and devices, including tools, machinery and equipment.

Duties of Mechanical Engineers

Mechanical engineers usually do the following:

Analyze issues to see how mechanical and heating devices can help a machine solve a particular problem

Designing or redesigning mechanical and heating devices or accessories using analytics and computer aided design

Investigate equipment failures or difficulties to detect operation malfunction and suggest solutions

Design Create and test prototypes of the devices they design

Results Examine the test results and modify the design or layout as needed

Oversee the manufacturing process for the device

Mechanical engineering is one of the broadest fields of engineering. Mechanical engineers design and oversee many products, from medical devices to new batteries.

Mechanical engineers design electric generators, internal combustion engines and generating engines such as steam and gas turbines, and electric machines such as air conditioning and air conditioning systems.

Mechanical engineers design other machines within buildings, such as elevators and escalators. They also design material-handling systems such as conveyor systems and automatic transmission stations.

Like other engineers, mechanical engineers use computers extensively. Mechanical engineers are usually responsible for integrating sensors, controllers and machinery. Computer technology enables mechanical engineers to create and analyze designs, run simulations and test how a machine may work, interact with connected systems, and create specifications for parts.

Examples of the following types of mechanical engineers:

Auto research engineers seek to improve the performance of cars. These engineers are working to improve the traditional features of cars such as suspension, and they are also working on aerodynamics and new potential fuels.

Engineers work to create and maintain ecosystems where temperature and humidity must be kept within certain limits. They make similar systems for planes, trains, cars, schools and even computer rooms.

Robot engineers design, build, and maintain robots. These engineers plan how robots use sensors to detect objects based on light or smell, and design how these sensors fit into the design of the robots.

Ground nut can kill the human ???????or save the life breaf explanation

Ground nut can kill the human ???????or save the life  breaf explanation

 

* Doctor's Enemy *

* Groundnut *

* Kills sugar *

In the field where groundnut is cultivated in our country there will not be so many rats in the field till the season when it bears nuts. But after the groundnut fruiting season, the rats can be seen to have overgrown. A good example of this is the peanut-eating goats, cows, dogs, and birds all around the field at the same time.

Peanuts are high in folic acid and reproduce quickly. Therefore, women who regularly eat peanuts have a smooth pregnancy and not only do not develop uterine tumors and cysts, but also with childbirth.

Preventing Diabetes:

Groundnut is rich in manganese. Manganese plays an important role in the conversion of nutrients and fats. Calcium from the food we eat is also used to get to our body. Women in particular can be protected from osteoporosis if they eat peanuts regularly.

Dissolving gallstones:

Eating 30 grams of groundnuts daily can help prevent gallstones. This information was revealed in a study conducted for 20 consecutive years.

Heart protection:

We think eating peanuts will put on weight. Not true. Conversely peanuts can also be eaten by those who think they should not gain weight. Groundnut is rich in resveratrol. It protects the heart valves. It also prevents heart disease. This is one of the best antioxidants.

Maintaining youth

It helps greatly in maintaining youth. Groundnut contains an antioxidant called polyphenols. It is used to prevent us from getting sick and to maintain youth.

Increases memory power:

Peanuts are like a good tonic for brain development. Groundnut contains vitamin 3 niacin which is used for brain development. It is very beneficial for brain development and memory. Regulates blood flow.

Depression:

Groundnut is rich in the essential amino acid baryptophan. This type of amino acid stimulates the brain called serotonin. Used to produce biochemicals. Serotonin stimulates the brain nerves. Relieves stress. Relieves stress for those who regularly eat peanuts.

Cholesterol triglyceride:

Those reading the title may be surprised. But that is the truth. Many of us would have thought that eating peanuts would be high in fat. But that is not true. Instead, peanuts contain fat that is good for humans. The copper and zinc nutrient in peanuts reduces the harmful fats in our body and increases the good fats. 100 grams of peanuts contain 24 grams of monounsaturated fat. Contains 16 grams of polyunsaturated fat.

These two types of fats are the fats that are good for our body. Peanuts have more beneficial fat than almonds. The omega-3 nutrient in peanuts boosts our body's immune system.

Groundnut attracts Americans:

India is the second largest producer of groundnut in the world after China. Groundnut is also a major contributor to the population of both countries. The practice of eating peanuts is a barrier to the sale of pediatric medicines in India and some heart medicines cannot be sold. So they spread misinformation about groundnut to Indians and stopped the use of groundnut and groundnut oils. This has led to an increase in childless couples.

For the last several years the price of groundnut in India has been selling at the same price without any major change. But over the same period, the share of peanuts in the American diet has increased 15 times and so has the price. Misinformation about groundnuts has been spread among Indians that Americans should buy groundnuts at a higher price if all Indians start eating groundnuts.

End of ovarian dysfunction:

Peanuts regulate the normal hormonal growth of women. This prevents women from having premature births and developing breast cancer in women. Groundnut is rich in folic acid, phosphorus, calcium, potassium, zinc, iron, vitamins and crutamic acid which are essential for women. It also prevents women from developing ovarian tumors and cysts.

* Rich in nutrients:

100 grams of groundnut is rich in the following nutrients.

Carbohydrate- 21 mg.

Fiber- 9 mg.

Soluble fat - 40 mg.

Protein - 25 mg.

Tryptophan- 0.24 g.

Tryonine - 0.85 kg

Isoleucine - 0.85 mg.

Leucine - 1.625 mg.

Lysine - 0.901 kg

Glutamic acid - 5 g

Glycine - 1.512 kg

Vitamin-B1, B2, B3, B1, B2, B3, B5, B6, C.

Calcium (Calcium) - 93.00 mg.

Copper - 11.44 mg.

 

Forging Process

 Forging process is perhaps the oldest metal working process and was known even during prehistoric days when metallic tools were made by heating and hammering.

Forging is basically involves plastic deformation of material between two dies to achieve desired configuration. Depending upon complexity of the part forging is carried out as open die forging and closed die forging.

In open die forging process, the metal is compressed by repeated blows by a mechanical hammer and shape is manipulated manually.

                                                  

                                                                          

In closed die forging, the desired configuration is obtained by squeezing the workpiece between two shaped between two shaped and closed dies.

 

In forging process the forces are applied on the raw material such that the stresses induced are greater than yield and less than ultimate so that material is experiencing plastic (or) permanent deformation to get required shape. But in forging operation force applied can be either continuous or intermittent impact loads.

 

Types of forging methods:

 

1 Based on the method of force application

1.      Hand forging (Drop hammer type)

2.      Machine forging (Mechanical or hydrostatic forging)

1.1 Hand forging:

Hand forging always uses drop hammer type. Because the continuous force by the human hand, it is not sufficient to produce the deformation in work piece.

1.2 Machine forging:

In machine forging because the required force is obtained from machine it is possible to use either continuous force application or intermittent impact load application.

 

2. Based on method of shape obtained

1.      Open die forging

2.      Closed die forging

3.      Semi die forging

2.1 Open die forging

§  In open die forging operation only drop hammer type of force application will be used.

§  Press forging is not used since there is no time fr changing the position of component.

Features of open die die forging:

§  Repeated impact blows are given on the work.

§  Less dimensional accuracy.

§  Suitable only for simple shapes of work.

§  Requires more skill of the operator.

§  Usually used for a work before subjecting it to closed die forging (to give approximate shape.

§  Dies are simple and less expensive.

§  It can be analyzed much easily.

§  it is the simplest of all forging operations.

2.2 Closed die forging

§  Closed die forging is also called as impression die forging because the shape of the dies is impressed on the component.

§  In this the type of forging force application may be either press forging type or drop hammer type will be used.

Features of closed die forging:

§  Closed die forging involves two or more steps:

1.      Blocking die: Work is rough forged, closed to final shape.

2.      Finishing die: Work is forged to final shape and dimension.

§  Both blocking die and finishing die are machined into the same die block.

§  More number of dies are required depending on the complexity of the job.

§  Two die halves close-in & work is deformed under high pressure.

§  High dimensional accuracy/close control on tolerances.

§  Suitable for complex shapes.

§  Dies are complex and more expensive.

§  Large production rates are necessary to justify high costs.

2.3 Semi closed die forging operation

§  Only drop hammer type of force application is possible.

§  In case of open die and closed die forging operations the volume of raw material required is remaining same as that of the volume of final finished component. But in case of closed die forging operation the volume of the raw material is about 10% to 20% more than final component to be obtained.

§  To accommodate the excess volume of material it is required to provide some open space dies also called gutter.

§  Because of provision of gutter the flash is produces in the forged component.

§  This flash is unwanted material which has to be removed by trimming operation.

§  Flash and gutter is used only in case of closed die operation but not in open die or semi closed die forging operation.

 

Advantages of forging:

Some common advantages of choosing forging operation are listed below:

1.      Forged parts possess high ductility and offers great resistance to impact and fatigue loads.

2.      Forging refines the structure of the metal.

3.      It results in considerable saving in time, labor and material as compared to the production process of similar item by cutting from a solid workpiece and then shaping it.

4.      Forging distorts the previously created unidirectional fiber as created by rolling and increases the strength by setting the direction of grains.

5.      The forged parts can be welded easily.

6.      Because of intense working, flaws are rarely found, so have high reliability.

7.      High accuracy may be obtained in forging operation.

 

Disadvantages of forging:

Few disadvantages of choosing forging operation are listed below:

1.      Rapid oxidation in forging of metal surface at high temperature results in scaling which wears the dies.

2.      It is difficult to maintain close tolerances in forging operations.

3.      Forging is limited to simple shapes and has limitation for parts having undercuts etc.

4.      Some materials are not readily worked by forging.

5.      The initial cost of forging dies and the cost of their maintenance is high.

6.      The metals gets cracked or distorted if worked below a specified temperature limit.

7.      The maintenance cost of forging dies is also very high.

 

Safety Precautions in Forging Shop

Some safety precautions in forging shop to followed while performing forging operation to avoid injuries and accidents are listed below:

 

1.      Always avoid the use of damaged hammers.

2.      Never try to strike a hardened surface with a hardened tool.

3.      No person should stand in line with the flying objects.

4.      Always use the proper tongs tool to grip and lift objects according to the type of work.

5.      The anvil should always be clean and free from moisture and grease while in use.

6.      Always wear proper clothes such as apron, foot-wears and goggles.

7.      The handle of the hammer should always be tightly fitted in the head of the hammer.

8.      Always put out the fire in the forge before leaving the forging shop.

9.      Always keep the working space clean and tidy.

10.  Proper safety guards should be provided on all revolving parts.

11.  Head of the chisel should be free from burrs and should never be allowed to spread.

12.  During machine forging, always observe the safety rules prescribed for each machine.

13.  One must have the thorough knowledge and working of the forging machine before going to operate it.

 

 

 

 

 

 

 

Best window cleaning Robert by prof.moses

            Best window cleaning Robert by prof. Moses 

 Hi my dear friends I  am writing this article about a best window cleaning Robert normally todays Roberts are  play wide role of  humans life , So below I mention some brand names below best cleaning Roberts 

• Best Overall: Hobot 298.

The Hobot 298 a robotic cleaner packed full of powerful and convenient features. This cleaner uses artificial intelligence to determine the most efficient route, and it keeps track of areas it has cleaned, allowing it to stop when the job is complete

• 
  
• Best Value: Fegrui R-C901.

This glass cleaning robot works surprisingly well. Better than I expected. We have some high up windows that I use to climb a ladder to clean. As we age ... the ladders aren't a good idea anymore so I started using a squeegee with a pole, not easy & was leaving streaks. Now I just place the glass robot and let it do it thing. It does need help with 'crusties' but for the most part I am very pleased with the initial operation.
Simple, easy and does a decent job. Nice product.
I'll update this review after we've been using it but we have initially found this to be a useful and well preforming product.
We usually don't leave reviews unless the product is either very poor or very pleased.
This item we are VERY PLEASED !

•