NVP Engineering services

01/09/2024

குதிரைகள் மட்டுமிங்கே
கொம்பின்றி பிறந்ததென்ன ?
வெறுப்புடன் பிறந்த மாக்கள்
பயத்தினைத் துணையாய்க் கொள்ள
விருப்புடன் பிறந்த குதிரைக்கு
கொம்பில்லை ; விஷமுமில்லை
தர்மத்தைச் சொல்ல வந்தோர்
தடியோடா காட்சி தருவர் ?

24/08/2024

21/07/2023

Its now r never deal🥵… Grab the hot before it coolsss .

09/02/2023

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14/10/2022

Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients.

Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore. These ingredients, when heated at high temperatures form a rock-like substance that is ground into the fine powder that we commonly think of as cement. The crushed rock is combined with other ingredients such as iron ore or fly ash and ground, mixed, and fed to a cement kiln.

The cement kiln heats all the ingredients to about 2,700 degrees Fahrenheit in huge cylindrical steel rotary kilns lined with special firebrick. Kilns are frequently as much as 12 feet in diameter and longer in many instances than the height of a 40-story building.

The finely ground raw material or the slurry is fed into the higher end. At the lower end is a roaring blast of flame, produced by precisely controlled burning of powdered coal, oil, alternative fuels, or gas under forced draft.

As the material moves through the kiln, certain elements are driven off in the form of gases. The remaining elements unite to form a new substance called clinker. Clinker comes out of the kiln as grey balls, about the size of marbles.

Clinker is discharged red-hot from the lower end of the kiln and generally is brought down to handling temperature in various types of coolers. The heated air from the coolers is returned to the kilns, a process that saves fuel and increases burning efficiency.

After the clinker is cooled, cement plants grind it and mix it with small amounts of gypsum and limestone.

06/10/2022

Correct air pressure in a tyre helps to distribute the weight of your vehicle evenly across the tyre’s tread pattern, so that the tyre – and the vehicle itself – is at its most stable. When a tyre is over- or under-inflated, it loses stability, negatively affecting handling, cornering and stopping. Eventually the tyre will also start to wear unevenly and … you’re heading for trouble.

04/10/2022

The fourth state of matter

Plasma is superheated matter – so hot that the electrons are ripped away from the atoms forming an ionized gas. It comprises over 99% of the visible universe. In the night sky, plasma glows in the form of stars, nebulas, and even the auroras that sometimes ripple above the north and south poles. That branch of lightning that cracks the sky is plasma, so are the neon signs along our city streets. And so is our sun, the star that makes life on earth possible.

Plasma is often called “the fourth state of matter,” along with solid, liquid and gas. Just as a liquid will boil, changing into a gas when energy is added, heating a gas will form a plasma – a soup of positively charged particles (ions) and negatively charged particles (electrons).

Because so much of the universe is made of plasma, its behavior and properties are of intense interest to scientists in many disciplines. Importantly, at the temperatures required for the goal of practical fusion energy, all matter is in the form of plasma. Researchers have used the properties of plasma as a charged gas to confine it with magnetic fields and to heat it to temperatures hotter than the core of the sun. Other researchers pursue plasmas for making computer chips, rocket propulsion, cleaning the environment, destroying biological hazards, healing wounds and other exciting applications.

03/10/2022

Firecrackers are the original fireworks. In their simplest form, firecrackers consist of gunpowder wrapped in paper, with a fuse. Gunpowder consists of 75% potassium nitrate (KNO 3), 15% charcoal (carbon) or sugar, and 10% sulfur. The materials will react with each other when enough heat is applied. Lighting the fuse supplies the heat to light a firecracker. The charcoal or sugar is the fuel. Potassium nitrate is the oxidizer, and sulfur moderates the reaction. Carbon (from the charcoal or sugar) plus oxygen (from the air and the potassium nitrate) forms carbon dioxide and energy. Potassium nitrate, sulfur, and carbon react to form nitrogen and carbon dioxide gases and potassium sulfide. The pressure from the expanding nitrogen and carbon dioxide explode the paper wrapper of a firecracker. The loud bang is the pop of the wrapper being blown apart #

01/10/2022

O-ring seal temperature ranges

All industrial o-ring purchases should be carefully planned with direct reference to the specific role and environment the seal is required to perform in. However, as a rough guide to o-ring temperature rating and use limits, some of the more popular materials on sale generally operate within the following sorts of temperature ranges:

Nitrile: anywhere from -50 C to 120 C
Hydrogenated nitrile: anywhere from -45 C to 150 C
Polyacrylate: anywhere from -25 C to 175 C
Ethylene-propylene: anywhere from -50 C to 135 C
Chloroprene: anywhere from -40 C to 120 C
Butyl (petroleum compound): anywhere from -55 C to 205 C
Fluorosilicone: anywhere from -60 C to 205 C
Fluorocarbon: anywhere from -25 C to 205 C

30/09/2022

Stress Relieving

Stress relieving is especially common for boiler parts, air bottles, accumulators, etc. This method takes the metal to a temperature just below its lower critical border. The cooling process is slow and therefore uniform.

This is done to relieve stresses that have built in up in the parts due to earlier processes such as forming, machining, rolling or straightening.

Tempering

Tempering is the process of reducing excess hardness, and therefore brittleness, induced during the hardening process. Internal stresses are also relieved. Undergoing this process can make a metal suitable for many applications that need such properties.

he temperatures are usually much lower than hardening temperatures. The higher the temperature used, the softer the final work piece becomes. The rate of cooling does not affect the metal structure during tempering and usually, the metal cools in still air.

Carburisation

In this heat treatment process, the metal is heated in the presence of another material that releases carbon on decomposition.

The released carbon is absorbed into the surface of the metal. The carbon content of the surface increases, making it harder than the inner core.

29/09/2022

Hardening

The most common heat treatment process of all, hardening is used to increase the hardness of a metal. In some cases, only the surface may be hardened.

A work piece is hardened by heating it to the specified temperature, then cooling it rapidly by submerging it into a cooling medium. Oil, brine or water may be used. The resulting part will have increased hardness and strength, but the brittleness increases too simultaneously.

Case hardening is a type of hardening process in which only the outer layer of the work piece is hardened. The process used is the same but as a thin outer layer is subjected to the process, the resultant work piece has a hard outer layer but a softer core.

This is common for shafts. A hard outer layer protects it from material wear. When mounting a bearing to a shaft, it may otherwise damage the surface and dislocate some particles that then accelerate the wearing process. A hardened surface provides protection from that and the core still has the necessary properties to handle fatigue stresses.

Other types of hardening processes include induction hardening, differential hardening and flame hardening. Flame hardening, however, may result in a heat affected zone that is created once the part is cooled.

Ageing

Ageing or precipitation hardening is a heat treatment method mostly used to increase the yield strength of malleable metals. The process produces uniformly dispersed particles within a metal’s grain structure which bring about changes in properties.

Precipitation hardening usually comes after another heat treatment process that reaches higher temperatures. Ageing, however, only elevates the temperature to medium levels and brings it down quickly again.

Some materials may age naturally (at room temperature) while others only age artificially, i.e. at elevated temperatures. For naturally ageing materials, it may be convenient to store them at lower temperatures.

28/09/2022

Annealing

In annealing, the metal is heated beyond the upper critical temperature and then cooled at a slow rate.

Annealing is carried out to soften the metal. It makes the metal more suitable for cold working and forming. It also enhances the metal’s machinability, ductility and toughness.

Annealing is also useful in relieving stresses in the part caused due to prior cold working processes. The plastic deformations present are removed during recrystallisation when the metal temperature crosses the upper critical temperature.

Metals may undergo a plethora of annealing techniques such as recrystallisation annealing, full annealing, partial annealing and final annealing.

Normalising

Normalising is a heat treatment process used for relieving internal stresses caused by processes such as welding, casting, or quenching.

In this process, the metal is heated to a temperature that is 40° C above its upper critical temperature.

This temperature is higher than the one used for hardening or annealing. After holding it at this temperature for a designated period of time, it is cooled in air. Normalising creates a uniform grain size and composition throughout the part.

Normalised steels are harder and stronger than annealed steel. In fact, in its normalised form, steel is tougher than in any other condition. This is why parts that require impact strength or need to support massive external loads will almost always be normalised.