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Mechanical Engineering

Mechanical Engineering is a branch of engineering that encompasses the generation and application of heat and mechanical power and the design, production, and use of machines and tools. Mechanical engineering involves application of the principles of dynamics, control, thermodynamics and heat transfer, fluid mechanics, strength of materials, materials science, electronics, and mathematics.

10,989 Questions

Does steel have an odor?

All matter has the potential to be smelt. Some we can smell easily and other things like Rocks and Metal are more difficult to smell...

But we have no problem smelling rust.

If its made of matter and it vibrates with its own special frequency then it has a smell...

All of the elements and all of the molecules that the elements make up have a smell...

You just may need a really sensitive nose...

But what smell is, is the atoms mixing frequency's as they very slowly evaporate and in-turn release their energy back to the universe.

All of our senses work on the principal of the detection of vibration and frequency.

What are the benefits of pneumatic control system?

nComponents have long working life resulting in longer system reliability nEnvironmentally friendly

nSafety issues are minimized e.g.. Fire hazards; unaffected by overloads (actuators stall or slip)

pneumatic actuators in a system do not produce heat (except for friction)

Where does the high tensile steels are used in the ship?

High Tensile Steel (HTS) is generally used for prestressing tendons.

What did Charles Goodyear invent by accident in 1839?

Charles Goodyear invented the process of vulcanisation of rubber.

Before the mid-19th century, natural or India rubber was limited in its usefulness because it melted in hot weather, froze and cracked in cold weather, and tended to stick to virtually everything. Charles Goodyear was a businessman who experimented with the properties of gum elastic. He accidentally discovered the process of vulcanisation of rubber when he dropped some rubber mixed with sulfur on a hot stove. Goodyear missed out on the financial benefits of his invention as Englishman Thomas Hancock copied his idea and attained a British patent for the process before Goodyear applied for a British patent. However, vulcanised rubber was later was made into tyres emblazoned with Goodyear's name.

Who invented springs?

I found one patent in the name of the Xerox corporation. United States Patent 3583505

Abstract:

A spring scale comprising, in a preferred embodiment, an upright tripod stand terminating at the upper portion thereof in a tripod head, an open sleeve in said head, a transparent graduated tube inserted therein with a spring in said tube connected at its lower end to a weighing pan.

There would be other patents as to other type or mechanism on another spring scale.

Why thermal conductivity value is important in engineering?

The Thermal Conductivity Value is important because it allows engineers or anyone find a material that insulates something like a shuttle to make sure that the extreme heat of re-entry or the extreme cold of space travel will not come in and boil astronauts or freeze them out. The lower the Thermal Conductivity Value the better it insulates.

Why is filet weld necessary while welding slip on flanges to a pipe end?

It is the only type of weld you can make to seal this type of joint. There are flange ends that can be welded onto pipe with a butt weld, but sockets and slip-ons must be fillet welded.

What is meant by gauges in measuring thickness of plates?

Gauge actually refers to the number of feet of iron wire it takes to weigh a pound....it takes 10 feet of 10 gauge iron wire to make a pound and it takes 30 feet of 30 gauge iron wire to make a pound.

at some point in time this got applied to sheet metal and this gauge system works about the same way.....the bigger the number the thinner the sheet metal.

Eg:

The higher the gauge, the thinner the metal. If I'm not mistaken gauge is measured in millimeters, only backwards.

Like in electrical wiring, 14 guage wire is about a 16th inch and 10 guage is almost a 1/4 inch etc. etc.

In otherwords, the lower the gauge the thicker it is.

Can the Yield strength of steel ever be greater than the Ultimate tensile strength?

The yield strength is reached when the material becomes non - linear ( that is non elastic) and takes a permanent set when load is released. Material stretches but does not break. Ultimate strength is when it breaks and is higher than yield strength.

What is dn50?

It stands for Deutsches Normung=German standard and usually applies to dimensional information in the metric system. Hence DN50 is for 50mm.

What Precautions required in arc welding?

Safety is important when welding. Make sure you have protective clothing (jacket, no frayed pants, helmet with proper shade, steel toe boots if material falls, etc.) Make sure people around you know your welding! Eye surgery sucks! NO Flammable liquids! (lacquer thinner is great for cleaning dirty metal before welding, but causes really big flames if you don't wipe off with a simple green type cleaner) Know where to kill the power if you have a problem, and where the extinguishers are VENTILATION! Clean air, good, welding fumes not so good.

Why the steam turbine needs preheating before the operating?

there are stages, fixed blades on the turbine shell and rotating blades on the rotor. They are very close together sooo, because the steam enters at one end of the turbine it heats that area first and it expands the metal there faster than at the other end causing it to rub. if you heat it slowly the turbine casing and the rotor grow at ~ the same rate so the stages don't rub together. If you heat too quickly,by just admitting a high volume of steam, the rotor heats up to fast, because of it has less metal to heat up, it rubs the fixed blades. this is called going long (the rotor is longer than the tolerances between the fixed blades on the casing)

What grade of steel is Q345B?

Q235A and Q235B, the main difference lies in the carbon content, carbon content of Q235A in 0.14-0.22, Q235B carbon content in 0.12-0.20

Relatively speaking Q235B mechanical performance is far superior to Q235A steel. Which Q235B do stamping experiment, Q235A do stamping experiment.

Q235A good toughness, has a certain degree of elongation, good welding and processing of. Q235A general in the hot state, the rolled steel, steel, steel plate, steel tube can be used for manufacturing various welding structures, bridges and generally not significant parts of the machine, such as bolts, rivets, pull rod, ring and the connecting rod.

Q235B has a certain degree of elongation, strength, good toughness and casting of. Ease of stamping and welding, widely used in general machinery parts manufacturing. Mainly used for construction, bridge engineering quality requirements of high structure.

Can pump discharge head be negative?

When a pump is pumping water from a level that is below the pump it is called suction head. If the water to be pumped is at a level above the pump, it is positive head. The pump maybe pumping from the base of a tank to a higher level such as an elevated tank or it may be pulling water from a tank that is below the pump. The distance from the center of the pump to the top of the water level would be the foot of head. It takes 2.31 feet to make 1 P.S.I. So if it is 10 feet from the center line of the pump to the water level, you would have about 4.33 P.S.I. of head.

How does a 4 way pneumatic valve work?

Moduflex dual valve combines two, 4-way valves into one valve body, it features two independently operated valves in the Size 1 valve body. :)

How you can improve the efficiency of lathe machine?

In order to increace the efficincy of a machine, you must eliminate losses of

energy between the input and the output. This almost always means reducing

or eliminating friction, either within the guts of the machine, or between the

machine's moving parts and the outside world. That's the reason that greases,

oil, other lubricants, and streamlining are so popular.

What are the 3 types or classes of levers?

A claw hammer is a lever when using the claw to pull a nail. A crowbar or pry bar is also a lever. Automobile friction jacks are also levers. Your arm is a biological (biomechanical) lever.

Name all subject you would need for mechanical engeneering?

If you are still at school, then i would say do your best in maths, Science (Physics), and tech. That is all you need really, although it is a bonus if you can get your GCSE in English and IT as well as you will not need to re-du these as a key skill at college.

Which is the heaviest mild steel or copper?

metal with out the properties that combine and then materialize into a base form of solid mass, or as known as carbon emulsified over and over repeatedly becomes a hairline, unlike brass metal.

How does the size of a ideal mechanical advantage compares to the mechanical advantage?

This is because the actual mechanical advantage is the actual calculation found after dividing the effort force by the output force. Ideal mechanical advantage is what many people would call and estimate. When estimating mechanical advantage, the numbers are always rounded. This makes actual mechanical advantage less.

Sources: Science teacher

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The answer above is incorrect.

The ideal mechanical advantage (IMA) is usually less than the mechanical advantage (MA) in a given machine because of the friction acting on the machine. There will always be some frictional resistance that increases the effort necessary to do the work.

What is tool steel 01?

  • Carbon (C) 0.95
  • Manganese (Mn) 1.2
  • Silicon (Si) 0.4
  • Chromium (Cr) 0.5
  • Tungsten (W) 0.5
  • Vanadium (V) 0.2
  • Phosphorus (P) 0.03
  • Max Sulfur (S) 0.03

What is the equivalent steel with Q235 grade steel in India?

Hot-rolled steel plate Q235A.

Equivalent standard:

JIS G3103/

JIS G3106/

ASTM A283/

EN10025/

ISO630

*Please notice that Q235A Chinese steel has exact equivalent by EuroNorms only.

This is S235JR.As for other countries the closest grades are ASTM A 750 Gr. 30 and Gr.40 (USA) and SS 400 and SM 400 B (Japan).

*The most closest AISI equivalent of Chinese Q235 is 1009.

*The equivalents of Chinese grade Q235 in Europe are S235JR, S235JRG1, S235JRG2, S235J2G3. As for USA there are many ASTM standards which covers this grade. We consider that the closest equivalent is UNS K 02502.

How do you change a bearing in a centrifugal pump?

A centrifugal pump is used on board most ships. There are many steps to overhaul one such as drain the pump, open the casing, remove the coupling, and replace the worn parts.