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The Magnetic Field Distribution In Alternative Current.   When the conductor is carrying Alternating Current, the internal magnetic field strength rises from zero at the centre to a maximum at the surface. However, the field is concentrated in a thin layer near the surface of  the conductor. This is known as the "skin effect."  The skin effect is evident in the field strength versus distance graph for a magnetic conductor shown to the right. The external field decreases with increasing distance from the surface as it does with DC. It should be remembered that with AC the fields constantly varying in strength and direction. In a hollow circular conductor there is no magnetic field in the void area. The magnetic field is zero at the inside wall surface and rises until it reaches a maximum at the outside wall surface. As with a solid conductor, when the conductor is a magnetic material, the field strength within the conductor is much greater than it was in the nonma...

As can be seen in the field distribution images, the field strength at the inside surface of hollow conductor carrying magnetic field produced by direct magnetization is very low. Therefore, the direct method of magnetization is not recommended when inspecting the inside diameter wall of a hollow component for shallow defects. The field strength increase rather rapidly as one moves in from the ID,so if the defect has significant depth, it may be detectable.However a much better method of magnetizing hollow component for inspection of the ID and OD surfaces is with the use of a central conductor. As can be seen in the field distribution image to the right, when current is passed through a nonmagnetic central conductor (copper bar), the magnetic field produced on the inside diameter surface of a magnetic tube is much greater and the field is still strong enough for defect detection on the OD surface. After conducting a magnetic particle inspection, it is usually necessary to demagneti...

Magnetic particle inspection. Today, most of the equipment used to create the magnetic field used in MPI is based on electromagnetism. That's, using an electrical current to produce the magnetic field. An Electromagnetic yoke is a very common piece of equipment that is used to establish a magnetic field. It is basically made by wrapping an electrical coil around a piece of soft ferromagnetic steel. A switch is included in the electrical circuit so that the current and, therefore, the magnetic field can be turned on and off. They can be powered with Alternating Current from a wall socket or by direct current from a battery pack. This type of magnet generates a very strong magnetic field in a local area where the poles of the magnet touch the part being inspected. Some yokes can lift weights in excess of 40 pounds.

Prods are handheld electrodes that are pressed against the surface of the component being inspected to make contact for passing electrical current through the metal. The current passing between the prods creates a circular magnetic field around the prods that can be used in magnetic particle inspection. prods are typically made from copper and have an insulated handle to help protect the operator. One of the prods has a trigger switch so that the current can be quickly and easily turned on and off. Sometimes the two prods are connected by any insulator (as shown in the image)  to facilitate one hand operation. This is referred to as a dual prod and is commonly used for weld inspections. If proper contact is not maintained between the prods and the component surface. electrical arcing can occur and cause damage to the component. For this reason, the use of prods are not allowed when inspecting aerospace and other critical components. To help prevent arcing, the prod tips sh...

Coils and conductive cables are used to establish a longitudinal Magnetic field within a component. When a preformed coils is used, the component is placed against the inside surface on the coil. Coils typically have three or five turns of a copper cable within the molded frame. A foot switch is often used is typically 00 extra flexible or 0000 extra flexible. The number of wraps is determined by the magnetizing force needed and of course, the length of the cable. Normally, the wraps are kept as close together as possible. When using a coil  or cable wrapped into a coil, amperage is usually expressed in ampere - turns. Ampere - turns is the amperage shown on the amp meter times the number of turns in the coil. PORTABLE POWER SUPPLIES :- Portable power supplies are used to provide the necessary electricity to the prods, coils or cables. Power supplies are commercially available in a variety of sizes. Small power supplies generally provide up to 1,500A of half - wave ...

 ADVANTAGES OF ULTRASONIC INSPECTION: -   1)   It is sensitive to both surface and subsurface discontinuities.          2)   The depth of penetration for flaw detection or measurement is superior to the NDT methods.  3)   Only single sided access is needed when the pulse echo technique is used.  4)   It is highly accurate in determining reflector position and estimating size and shape.                                     5)   Minimal part preparation is required.                                                                                    6)   Electronic equipment provides instantaneo...

Disadvantages of computers : 1)   Health issues: Excessive computer use can lead to health problems such as eye strain, back and neck pain, and musculoskeletal disorders. Prolonged sitting and sedentary behavior can also contribute to obesity and other lifestyle diseases. 2)   Security risks: Computers are susceptible to security threats such as viruses, malware, and hacking. Users must take precautions, such as using antivirus software and strong passwords, to protect their personal information and data. 3)   Dependency: As people become reliant on computers for various tasks, there is a risk of dependency and loss of manual skills. Additionally, technical issues or power outages can disrupt productivity and cause frustration. 4)   Social isolation: Spending excessive time on computers can lead to social isolation and a lack of face-to-face interaction. Virtual communication may not provide the same level of human connection as in-per...

Stationary magnetic particle inspection equipment is designed for use in laboratory or production environment. The most stationary system is the wet horizontal (bench) unit. Wet horizontal units are designed to allow for batch inspections of a variety of components. The units have head and tail stocks (similar to lathe) with electrical contact that the part can be clamped between. A circular magnetic field is produced with direct magnetization.  The tail stock can be moved and locked into place to accommodate parts of various lengths. To assist the operator in clamping the parts, the contact on the headstock can be moved pneumatically via a foot switch. Most units also have a movable coil that can be moved into place so the indirect magnetization can be used to produce a longitudinal Magnetic field. Most coils have five turns and can be obtained in a variety of sizes. The wet magnetic particle solution is collected and held in a tank. A pump and hose system is used to appl...

                      If you ever buy a new car, there are a few things about it that no one can guarantee, one of which is that your car will definitely get a dent at some point.  This is because no matter how much you save, some person walking on the road sometimes collides with your car a little, due to which your car gets dented, for which you may have to spend thousands of rupees to remove it.  Are.  If you have also bought a new car recently and there is a small dent in it, which you want to get removed but do not want to spend money, then today we are going to tell you a very easy way to remove the dent at home.                Once your car gets a dent, you can take it out with boiled water if you want, for this you will have to take about 1 liter of hot water which is boiled, after that pour this water little by little on the dent.  .  As soon ...

Advantages of computer. 1)   Efficiency: Computers can process large amounts of data quickly and accurately, increasing productivity and efficiency in various tasks, including data analysis, calculations, and communication. 2)   Storage: Computers have the ability to store vast amounts of data, eliminating the need for physical paper files and allowing for easy organization and retrieval of information. 3)   Communication: Computers enable instant communication through email, messaging apps, video conferencing, and social media platforms, connecting people globally and facilitating collaboration and information sharing. 4)   Automation: Computers can automate repetitive tasks, reducing human error and freeing up time for more complex and creative work. 5)   Access to information: The internet provides access to a wealth of information and resources, allowing users to search for information, learn new skills, and stay informed...

Summer has wreaked havoc, as soon as you come home, you feel like having cold water or a cold drink to enjoy yourself.  But none of us is unaware of the condition of electricity in the cities.  In such a situation, getting some cool water is very useful.          Summer has wreaked havoc, as soon as you come home, you feel like having cold water or a cold drink to enjoy yourself.  But none of us is unaware of the condition of electricity in the cities.  In such a situation, it becomes very difficult to get any cold water.  To solve this problem, we have come up with an idea that will work to keep water and other drinks cool without electricity.  Yes, we are talking about home made fridge.  With this fridge, you can keep drinks and water cool.  So let us tell you how to make this fridge. 1. For this, first of all you will need two pots (one big pot and one small pot) and sand. 2. Now fill some sand in the big po...

To inspect a part using a head - shot, the part is clamped between two electrical contact pads. The magnetic solution,called a bath, is then flowed over the surface of the part. The bath is then interrupted and magnetizing current is applied to the part for a short duration. typically 0.5 to 1.5 seconds.(precautions should be taken to prevent burning or overheating of the part)  A circular field flowing around the circumstances of the part is created. Leakage fields from defects then attract the particles to form indications. When the coil is used to establish a longitudinal Magnetic field within the part is placed on the inside surface of the coil. Just as done with a head shot, the bath is then flowed over the surface of the part. A magnetizing current is applied to the part for a short duration, typically 0.5 to 1.5 seconds, just after coverage with the bath is interrupted. (Precautions should be taken to prevent burning or overheating of the part) Leakag...

While television has many advantages, it also has some disadvantages: 1)   Time-consuming: Excessive television viewing can be time-consuming, leading to a lack of productivity and neglect of other important activities such as studying, exercising, and socializing. Spending too much time in front of the TV can result in a sedentary lifestyle and contribute to health issues like obesity . 2)   Negative impact on physical health: Watching television for long periods can lead to a sedentary lifestyle, which is associated with various health problems such as obesity, heart disease, diabetes, and back problems. Additionally, excessive screen time can strain the eyes and cause vision problems. 3)   Exposure to inappropriate content: Television programs can sometimes contain violence, explicit language, and mature themes that may not be suitable for all viewers, especially children. Unsupervised viewing or lack of proper content filters can expose indi...

Multidirectional units allow the component to be magnetized in two directions, longitudinally and circumferentially, in rapid succession.  Therefore, inspections are conducted without the need for a second shot in multidirectional units, the two fields are balanced so that the field strength are equal in both directions. These quickly changing balanced fields a multidirectional field in the component detection of defects lying in more than one direction. Just as conventional wet-hirizontal systems the electrical current used in multidirectional magnetization may be Alternating half-wave direct, or full-sized. It is also possible to use a combination of currents depending on the test applications.Multidirectional magnetization can be used for a large number of production application, and high volume inspections. To determine adequate field strength and balance of the rapidly changing fields,techniques development requires a little more effort when multirectional equipment is us...

There are several advantages of television: 1)   Source of Information and Education: Television provides a wide range of channels and programs that offer news, documentaries, educational shows, and other informative content. It allows viewers to stay updated on current events, learn about different topics, and gain knowledge in various fields. 2)   Entertainment and Relaxation: Television is a popular form of entertainment, offering a wide variety of shows, movies, sports events, and dramas. It provides a means of relaxation and escapism, allowing viewers to unwind and enjoy their favorite programs. 3)   Visual and Audio Medium: Television is a visual and audio medium, making it an engaging form of communication. It allows viewers to see and hear what is happening, bringing stories and events to life. This can enhance the entertainment value and helps in conveying information effectively. 4)   Cultural Exchange and Global Awareness: T...

Magnetic particle inspection can be performed using particles that are highly visible under white light conditions or particles that are highly visible under ultraviolet light conditions. When an inspection is being performed using the visible color contrast particles, no special lighting is required as long as the area of inspection is well lit.A light intensity of at least 1000 lux (100fc) is recommended when visible particles are used, but a variety of light sources can be used. When fluorescent particles are used, special ultraviolet light must be used. Fluorescence is defined as the property. of emitting radiation as a result of and during exposure to radiation. Particles used in fluorescent magnetic particle inspections are coated with a material that produces light in the visible spectrum when exposed to near - ultraviolet light. This "particle glow" provides high contrast indications on the component anywhere particles collect. Particles that fluoresce yellow ...

Ultraviolet light or "black light"  is light in the 1000 to 4000 Angstroms (100 to 400nm) wavelength range in the Electromagnetic spectrum. It is a very energetic form of light that is invisible to the human eye.wavelengths above 4000A fall into the visible spectrum and are seen as the color violet. UV is separated according to wavelength into three classes : A, B' and C. The shorter the wavelength, the more energy that is carried in the light and the more dangerous it is to the human cells. The desired wavelength range for use in nondestructive testing is between 3500 and 3800A with a peak wavelength at about 3650A. This wavelength range is used because it is in the UV-A range, which is the safest to work with. UV-B will do an effective job of causing substances to fluoresce, however, it should not be used because harmful effects such as skin burns and eye damage can occur. This wavelength of radiation is found in the arc created during the welding process. UV-C (100...

A Gauss meter with a Hall Effect probe is commonly used to measure the tangential field strength on the surface of the part. As discussed in some detail on the measuring magnetic fields page the Hall Effect is the transverse electric field created in a conductor when placed in a magnetic field. Gauss meters, also called Tesla meters, are used to measure the strength of a field tangential to the surface of the magnetized test object. The meters measure the intensity of the field in the air adjacent to the component when a magnetic field is applied. The advantages of Hall effect devices are: they provide a quantitative measure of the strength of magnetizing force tangential to the surface of a test piece, they can be used for measurement of residual magnetic fields, and they can be used repetitively. Their main disadvantages are that they must be periodically calibrated and they cannot be used to establish the balance of fields in multidirectional applications.

The 400 watt metal halide bulbs or "super light" can be found in some facilities. This super bright will provide adequate lighting over an area of up to ten times that covered by the 100 watt bulb. Due to their high intensity, excessive light reflecting from the surface of a component is a concern. Moving the light a greater distance from the inspection area will generally reduce this glare. Another type of high intensity light available is the micro - discharge light. This particular light produces up to ten times the amount of UV light conventional lights produce. Reading of up to 60,000 uW/cm2 at 15 inches can be achieved. Determining whether a magnetic field is of adequate strength and in the proper direction is critical when performing magnetic particle testing. As discussed previously, knowing the direction of the field is important because the field should be as close to perpendicular to the defect as possible and no more than 45degrees from normal. Being able to e...

The work of a computer involves a series of tasks performed by its hardware and software components. Here is a general overview of how a computer works: 1) . Input: Users interact with the computer by providing input through devices like keyboards, mice, touchscreens, or voice recognition systems. This input can include commands, data, or instructions 2)   Processing: The computer's central processing unit (CPU) performs calculations, executes instructions, and manages data. It retrieves instructions from memory, decodes them, and performs the necessary operations. 3).  Memory: The computer's memory stores both data and program instructions. It consists of volatile random access memory (RAM) that provides temporary storage for data and instructions currently in use, and non-volatile storage like hard drives or solid-state drives (SSDs) for long-term storage of data and programs. 4).  Output: The results of the computer's processing are presented to t...

A metal laser cutting machine uses a high-powered laser beam to cut through various types of metal materials. Here is a general overview of how a metal laser cutting machine works: 1).  Setup: The operator sets up the metal laser cutting machine by loading the metal workpiece onto the machine's cutting bed or table. The workpiece is securely clamped in place to prevent movement during the cutting process. 2).  Programming: The desired cutting pattern or design is programmed into the machine's control system. This can be done manually or using computer numerical control (CNC) programming. 3).  Laser Beam Generation: The laser cutting machine generates a high-powered laser beam using a laser source, such as a CO2 laser or a fiber laser. The laser beam is directed through a series of mirrors and lenses to focus the beam to a small spot size. 4).  Cutting Process: The focused laser beam is directed onto the surface of the metal workpiece. The intense heat of ...

When a current carrying conductor is formed into a loop or several loops to from a coil, a magnetic field develops that flows through the center of the loop or coil along its longitudinal axis and circles back around the outside of the loop or coil. The magnetic field circling each loop of wire combines with the fields from the other loops to produce a concentrated field down the center of the coil. A loosely wound coil is illustrated below to show the interaction of the magnetic field. The magnetic field is essentially uniform down the length of the coil when it is wound tighter. The strength of a coils magnetic field increases not only with increasing current but also with each loop that is added to the coil. A long, straight coil of wire is called a solenoid and can be used to generate a nearly uniform magnetic field similar to that of a bar magnet. The concentrated magnetic field inside a coil is very useful in magnetizing ferromagnetic materials for inspection using the ma...

Magnets are not the only source of magnetic field. In 1820, Hans christian oersted discovered that an electric current flowing through a wire caused a nearby compass to deflect. This indicated that the current in the wire was generating a magnetic field. Oersted studied the nature of the magnetic field around the long straight wire. He found that the magnetic field existed in circular From around the wire and that the intensity of the field was directly proportional to the amount of current carried by the wire. He also found that the strength of the field was strongest next to the wire and diminished with distance from the conductor until it could no longer be detected. In most conductors,the magnetic field exists only as long as the current is flow (i.e.an electrical charge is in motion).  However, in ferromagnetic materials the electric current will cause some or all of the magnetic Domains to align and a residual magnetic field will remain. Oersted also noticed that the di...

Magnets come in a variety of shapes and one of the more common is the horseshoe (U) magnet. The horseshoe magnet has north and south poles just like a bar magnet but the magnet is curved so the poles lie in the same plane. The  magnetic lines of force flow from Pole to pole just like in the bar magnet. However, since the poles are located closer together and a more direct path exists for the lines of flux to travel between the poles, the magnetic field is concentrated between the poles. If a bar magnet was placed across the end of a horseshoe magnet or if a magnet was formed in the shape of a ring, the lines of magnetic force would not even need to enter the air.The value of such a magnet where the magnetic field is completely contained with the material probably has limited use. However, it is important to understand that the magnetic field can flow in loop within a material. 

A metal bending machine, also known as a press brake, is a machine tool used to bend or shape metal workpieces. Here is a general overview of how a metal bending machine works: 1)  Setup: The operator sets up the metal bending machine by attaching the required tooling, such as a punch and a die, onto the machine's ram and bed. 2)  Material Placement: The operator then places the metal workpiece, such as a sheet or plate, onto the machine's bed, aligning it with the desired bending line. 3)  Programming: Depending on the complexity of the bend, the operator may need to program the machine with the desired bending angle, bend radius, and other parameters. This can be done manually or using computer numerical control (CNC) programming. 4)  Clamping: The workpiece is securely clamped against the machine's bed and back gauge to prevent movement during the bending process. 5).  Bending: The machine's ram, which is equipped with the punch, descends and appl...

A magnetic field is a change in energy within a volume of space. The magnetic field surrounding a bar magnet can be seen in the magnetograph below. A magnetograph can be created by placing a piece of paper over over a magnet and sprinkling the paper with iron filings. The particles align themselves with the line of magnetic force produced by the magnet. The magnetic lines of force show where the magnetic field exits the material at one pole and reenters the material at another pole along the length of the magnet. It should be noted that the magnetic lines of force exits in three dimensions but are only seen in two dimensions in the image. It can be seen in the magnetograph that there are poles all along the length of the magnet but that the poles are concentrated at the ends of the magnet. The area where the exit poles are concentrated is called the magnets north pole and the area where the entrance poles are concentrated is called the magnets south pole.

Ferromagnetic materials get their magnetic properties not only because their atoms carry a magnetic moment but also because the material is made up of small regions known as magnetic Domains.  In each domain, all of the atomic dipoles are coupled together in a preferential direction. This alignment develops as the material develop ls it's crystalline structure during solidification from the molten state. Magnetic Domains can be detected using magnetic force Microscopy (Mum)and images of the domains like the one shown below can be constructed. during solidification, a trillion or more moments are aligned parallel so that the magnetic force within the domain is strong in one direction. Ferromagnetic materials are said to be characterized by spontaneousm magnetization since they obtain saturation magnetization in each of the domains without an external magnetic field being applied.  Even though the domains are magnetically saturated  the bulk material may not show A...

All matter is composed of atoms, and atoms are composed of protons and electrons.The protons and neutrons are located in the atoms nucleus and the electrons are in constant motion around the nucleus. Electrons carry a negative electrical charge and produce a magnetic field as they move through space..A magnetic field is produced whenever an electrical charge is in motion. The strength of this field is called the magnetic moment. This may be hard to visualize on a subatomic scale but consider electric current flowing through a conductor. When the electrons ( electric current)  are flowing through the conductor, a magnetic field forms around the conductor. The magne field can be detected using a compass. The magnetic field will place a force on the compass needle, which is another example of a dipole. Since all matter is comprised of atoms, all materials are affected in some way by a magnetic field. However, not all materials react the same way. This will be explored mo...

Magnets are very common items in the workplace and household. Uses of magnets range from holding pictures on the refrigerator to the causing torque in electric motors. Most people are familiar with the general properties of magnets but are less familiar with the source of magnetism. The traditional concept of magnetism centres around the magnetic field and what is know as a dipole. The term magnetic field, simply describes a volume of space where there is a change in energy within that volume. This change in energy can be detected and measured. The location where a magnetic field can be detected existing or entering a material is called a magnetic pole. Magnetic poles have never been detected in isolation but always occur in pairs, hence the name dipole. Therefore, a dipole is an object that has a magnetic pole on one end a second, equal but opposite, magnetic pole on the other A bar magnet can be considered a dipole with a north pole at one end south pole at the other. A magnetic ...

Magnetism is the ability of matter to attract other to itself. The ancient Greeks were the first to discover this phenomenon in a mineral they named magnetite. Later on Bergmann, Becharee, and Faraday discovered that all matter including liquids and gasses were affected by magnetism, but only a few responded to a noticeable extent. The earliest known use of magnetism to inspect took place as early as 1868. Cannon barrels were checked for defects by magnetizing the barrel then sliding a magnetic compass along the barrels length. These early inspectors were able to locate flaws in the barrels by monitoring the needle of the compass. This was a form of nondestructive testing but the term was not commonly used until some time after world war 1. In the early 1920s, William Hoke realized that magnetic particle ( colored metal shavings) could be used with magnetism as a means of locating defects. Hoke discovered that a surface or subsurface flaw in a magnetized material caused the magnet...

In the theory, magnetic particle inspection (MPI) is a relatively simple concept. It can be considered as a combination of two nondestructive testing methods: magnetic flux leakage testing and visual testing. Consider the case of a bar magnet. It has a magnetic field in and around the magnet. Any place that a magnetic line of force exits or enters the magnet is called a pole. A pole where a magnetic line of force exits the magnetic is called a north pole and a pole where a line of force enters the magnet is called a south pole. When a bar magnet is broken in the center of its length, two complete bar magnet with magnetic poles on each end of each piece will result. If the magnetic is just cracked but not broken completely in two, a north and south pole will form at each edge of the crack. The magnetic field exits the north pole and reenters at the south pole. The magnetic field spreads out when it encounters the small air gap created by crack because the air cannot support as much ...

Road bridges have a long and fascinating history that dates back thousands of years. Here is a brief overview of the development and evolution of road bridges: 1). Ancient and Medieval Times: *  The earliest known road bridges were built by ancient civilizations such as the Romans, Greeks, and Egyptians. *The Romans constructed a vast network of roads and bridges throughout their empire, using techniques such as arches and stone construction. *During the Middle Ages, bridge building techniques continued to evolve, with the use of timber and masonry construction. *Bridge design during this period was influenced by the need for crossing rivers, moats, and other natural or man-made obstacles. 2).  Renaissance Period: * In the Renaissance era, advancements in engineering and architecture led to the development of more sophisticated bridge designs. *The use of arches, pillars, and fortified structures became common in bridge construction. *Prominent examples f...

Magnetic particle inspection (MPI) is a nondestructive testing method used for defect detection MPI is fast and relatively easy to apply, and part surface preparation is not as critical as it is some other NDT methods. These characteristics make MPI one of the most widely utilized nondestructive testing methods. MPI uses magnetic field and small magnetic particle (I.e.iron filings) to detect flaws in component. The only requirement from inspectability standpoint is that the component being must be made of a ferromagnetic material such as iron, nickel, or some of their alloys. Ferromagnetic materials are materials that can be magnetized to a level that will allow the inspection to be affective. The method is used to inspect a variety of product including castings,forgings,and weldments. Many different industries use magnetic particle inspection for determining a components fitness - for - use. Some examples of industries that use magnetic particle inspection are the structural stee...

The second step in the inspection involves using an angle beam transducer to inspect the actual weld. Angle beam transducers use the principal of refraction and mode conversion to produce refrected shear or longitudinal waves in the test material. This inspection may include the root,sidewall, Crown, and heat- affected zones of a weld. The process involves scanning the surface of the material around the weldment with the transducer. This refracted sound wave will bounce off a reflector ( discontinuity)  in the path of the sound beam. Will proper angle beam techniques, echoes returned from the weld zone may allow the operator to determine the location and type of discontinuity. To determine the proper scanning area for the welder,the inspector must first calculator the location of the sound beam in the test material. Using the refracted angle, beam index point and material thickness, the V-path and skip distance of the sound beam is found. Once they have been calculated, the ...

The following is a general procedure for making stainless steel utensils: 1)   Design and Planning: Determine the specific type of utensil to be manufactured, considering its size, shape, and functionality. Create a detailed design and gather the necessary measurements. 2).  Material Selection: Choose the appropriate grade of stainless steel for the utensil based on its intended use. Stainless steel is an alloy composed primarily of iron, with varying amounts of chromium and other elements for added corrosion resistance and strength. 3).   Cutting and Shaping: Use cutting equipment such as shears or laser cutting machines to shape the stainless steel sheets into the desired size and shape for the utensil. This may involve cutting out flat pieces or using specialized dies or molds for more complex shapes. 4)   Forming and Bending: Utilize techniques like bending, rolling, or stamping to shape the stainless steel pieces into the desired form....

Best technical knowledge: WELDMENTS ( welded joints) in ultrasonic inspection. : The most commonly occurring defects in welded joints are porosity, Slag inclusions, lack of side - wall fusion, lack of inter - run fusio...

The most commonly occurring defects in welded joints are porosity, Slag inclusions, lack of side - wall fusion, lack of inter - run fusion, lack of  root penetration, undercutting, and longitudinal or transverse cracks. With the exception of signal gas pores all the defects listed are usually well detectable by ultrasonic. Most applications are on low-alloy construction quality steels,however, world's in aluminium can also be tested. Ultrasonic flaw detection has long been the preferred method for nondestructive testing in welding application. This safe,accurate, and simple technique has pushed ultrasonics to the forefront of inspection technology. Ultrasonic weld inspections are typically performed using a straight beam transducer in conjunction with an angle beam transducer and wedge. A straight beam transducer, producing a longitudinal wave at normal incident into the test piece, is first used to locate any laminations in important because an angle beam transducer may not a...

Rail inspections were initially performed solely means. Ofcourse, visual inspections will only detect external defects and sometimes the subtle signs of large internal problems. The need for a better inspection Methley became a high priority because of aderailment at Manchester, NY in 1911, in which 29 people were killed and 60 were seriously injured. In the U.S bureau of safety's ( now the national transportation safety board)  investigation of the accident, a broken rail was determined to be the cause of the derailment. The bureau established that the rail failure was caused by defect that entirely internal and probably could not have been detected by visual means. The defect was called a transverse fissure ( example shown on the left).  The railroads began investigating the prevalence of this defect and found transverse fissures were widespread. One of the methods used to inspect rail is ultrasonic inspection. Both normal - and angle - beam techniques are used, as are b...

Distance calibration Block :-The DC AWS block is a metal path distance and beam exit point calibration standard that conforms to the requirements of the American welding society (AWS) and the American association of state highway and transportation officials ( AASHTO).  Instructions on using the DC block can be found in the annex of American society for testing and materials standard E164, standard practice for ultrasonic contact Examination of weldments. RESOLUTION CALIBRATION BLOCK :-The RC block is used to determine the resolution of angle beam transducers per the requirements of AWS and AASHTO. engraved index markers are provided for 45,60, and 70 degree refracted angle beams.

The history of watches dates back to ancient times, with the evolution of timekeeping devices. Here is a brief overview of the key milestones in the history of watches. 1).   Sundials and Water Clocks: *  Ancient Egypt and Greece: Sundials were used to measure time based on the position of the sun. Water clocks, also known as clepsydras, used water flow to track time. 2).  Early Mechanical Clocks: * Middle Ages: Mechanical clocks were developed, initially driven by weights or springs, and powered by pendulums or gears. These large clocks were typically found in public spaces or religious institutions 3) Portable Timepieces: * 16th Century: The invention of the mainspring allowed for the development of smaller, portable timekeeping devices. The first portable watches, known as "clock-watches," were carried in pockets or worn around the neck. 4). Pocket Watches: *17th Century: The introduction of a balance wheel mechanism replaced the use of ...