High-frequency welding is included in a group of resistance welding process variations that use high-frequency welding current (1kHz to 800kHz) to concentrate the welding heat at the desired location.
The heat produces the coalescence of metals, and an upsetting force usually is applied to produce a forged weld.
High-frequency resistance welding is an automated process and is not adaptable to manual welding.
High-frequency resistance welding was developed during the late 1940s and early 1950s to fill the need for high-integrity butt joints and seam welds in pipe and tubing.
But today the process is also used in the manufacture of products such as spiral-fin boiler tubes, closed roll form shapes, and welded structural beams.
A wide range of commonly used metals can be welded, including low-carbon and alloy steels, ferritic and austenitic stainless steels, and many aluminum, copper, titanium, and nickel alloys.
HFW is based on two main electrical phenomena
Skin effect
Proximity effect
Mr. Mubassir I. Ghoniya has satisfactorily completed his term work in mechanical engineering at the university. The document then discusses the definition of weldability as the ease with which two metals can be joined together through welding. It outlines several factors that affect the weldability of metals, such as melting point, thermal conductivity, and surface condition. Metals with better weldability like iron and steel are easier to weld and provide mechanically sound joints.
Electric arc welding is a process that joins metals by heating them with an electric arc between an electrode and the metals. It is one of the most common welding processes and uses a consumable electrode coated in flux to lay the weld. The electric arc melts the tip of the electrode and filler metal is deposited into the weld pool while the flux provides shielding from contamination and leaves a slag layer. Proper welding techniques along with the right equipment, electrodes, and power source are required to perform arc welding.
The document discusses various metal joining processes, focusing on welding. It describes different types of welding processes, including arc welding, gas welding, resistance welding, and solid state welding. For arc welding processes specifically, it explains gas metal arc welding (MIG), shielded metal arc welding (SMAW), submerged arc welding (SAW), and the consumable electrodes, shielding gases, and power sources used.
The document discusses the weldability of various stainless steel types, including austenitic, ferritic, and martensitic stainless steels. It provides information on their typical compositions and applications. It also describes various welding techniques that can be used and issues that may occur during welding like sensitization, sigma phase formation, and hydrogen cracking. Prevention methods are outlined like using stabilizers, annealing treatments, and controlling cooling rates and heat inputs during welding.
The document provides an overview of various fusion welding processes. It discusses oxyfuel gas welding, arc welding processes using consumable electrodes like shielded metal arc welding and flux-cored arc welding. It also covers non-consumable electrode processes such as electroslag welding, where an arc is started and then heat is produced through electrical resistance in molten slag. Safety practices and equipment used for different welding types like gas metal arc welding are also summarized.
1. Sheet metal forming operations include bending, stretching, deep drawing, and other processes where sheets are formed. Bending involves shaping a straight length into a curve and can be done using presses or rolls.
2. Deep drawing uses a die and punch to shape flat sheets into cup-shaped parts. Stretch forming clamps sheet edges and stretches the sheet over a die into the desired shape.
3. Successful forming requires considering the material properties, die and process parameters to avoid defects like cracks, wrinkles, and non-uniform thinning. Minimum bend radii, lubrication, and holding pressure all impact the quality of formed parts.
This document discusses welding defects and their causes. It outlines the four zones in a welded joint and how they appear on an iron-carbon phase diagram. The zones are the fusion zone, weld interface zone, heat affected zone, and base metal. Solidification can be epitaxial or non-epitaxial depending on whether filler metal is used. Common welding defects include cracks, porosity, inclusions, incomplete fusion, imperfect shape, and residual stresses. Various defect types like longitudinal cracks and underbead cracks are described in more detail.
Soldering and brazing are processes used to join metal pieces. Soldering uses a lower melting point filler metal to join parts, while brazing uses higher temperatures above 450°C for the filler metal to melt without melting the parts. Common soldering tools and techniques were discussed, along with advantages like low heat and joining dissimilar metals, and disadvantages like low joint strength. Brazing methods like torch, furnace, and induction brazing were also outlined, along with advantages like joining any metals but disadvantages of potentially weaker joints at high temperatures.
Mr. Mubassir I. Ghoniya has satisfactorily completed his term work in mechanical engineering at the university. The document then discusses the definition of weldability as the ease with which two metals can be joined together through welding. It outlines several factors that affect the weldability of metals, such as melting point, thermal conductivity, and surface condition. Metals with better weldability like iron and steel are easier to weld and provide mechanically sound joints.
Electric arc welding is a process that joins metals by heating them with an electric arc between an electrode and the metals. It is one of the most common welding processes and uses a consumable electrode coated in flux to lay the weld. The electric arc melts the tip of the electrode and filler metal is deposited into the weld pool while the flux provides shielding from contamination and leaves a slag layer. Proper welding techniques along with the right equipment, electrodes, and power source are required to perform arc welding.
The document discusses various metal joining processes, focusing on welding. It describes different types of welding processes, including arc welding, gas welding, resistance welding, and solid state welding. For arc welding processes specifically, it explains gas metal arc welding (MIG), shielded metal arc welding (SMAW), submerged arc welding (SAW), and the consumable electrodes, shielding gases, and power sources used.
The document discusses the weldability of various stainless steel types, including austenitic, ferritic, and martensitic stainless steels. It provides information on their typical compositions and applications. It also describes various welding techniques that can be used and issues that may occur during welding like sensitization, sigma phase formation, and hydrogen cracking. Prevention methods are outlined like using stabilizers, annealing treatments, and controlling cooling rates and heat inputs during welding.
The document provides an overview of various fusion welding processes. It discusses oxyfuel gas welding, arc welding processes using consumable electrodes like shielded metal arc welding and flux-cored arc welding. It also covers non-consumable electrode processes such as electroslag welding, where an arc is started and then heat is produced through electrical resistance in molten slag. Safety practices and equipment used for different welding types like gas metal arc welding are also summarized.
1. Sheet metal forming operations include bending, stretching, deep drawing, and other processes where sheets are formed. Bending involves shaping a straight length into a curve and can be done using presses or rolls.
2. Deep drawing uses a die and punch to shape flat sheets into cup-shaped parts. Stretch forming clamps sheet edges and stretches the sheet over a die into the desired shape.
3. Successful forming requires considering the material properties, die and process parameters to avoid defects like cracks, wrinkles, and non-uniform thinning. Minimum bend radii, lubrication, and holding pressure all impact the quality of formed parts.
This document discusses welding defects and their causes. It outlines the four zones in a welded joint and how they appear on an iron-carbon phase diagram. The zones are the fusion zone, weld interface zone, heat affected zone, and base metal. Solidification can be epitaxial or non-epitaxial depending on whether filler metal is used. Common welding defects include cracks, porosity, inclusions, incomplete fusion, imperfect shape, and residual stresses. Various defect types like longitudinal cracks and underbead cracks are described in more detail.
Soldering and brazing are processes used to join metal pieces. Soldering uses a lower melting point filler metal to join parts, while brazing uses higher temperatures above 450°C for the filler metal to melt without melting the parts. Common soldering tools and techniques were discussed, along with advantages like low heat and joining dissimilar metals, and disadvantages like low joint strength. Brazing methods like torch, furnace, and induction brazing were also outlined, along with advantages like joining any metals but disadvantages of potentially weaker joints at high temperatures.
This document provides terminology related to welding codes and qualifications. It defines key terms like essential variables, non-essential variables, and supplementary variables. It also discusses welding terminology like weld beads, types of joints, and weld positions. The document is part of a larger guide on welding qualification simplified according to the ASME IX Code and covers topics like steel welding metallurgy, welding processes, weld symbols, and acceptance criteria for welds.
The document discusses various metal forming processes used to change the shape of metal workpieces through plastic deformation exceeding the metal's yield strength, including bulk deformation techniques like rolling, forging, and extrusion that involve significant shape changes with lower surface area to volume ratios, and sheet metalworking techniques like bending, drawing, and shearing that are performed on metal sheets or strips with higher surface area to volume ratios. Metal forming is an important manufacturing method that allows for net or near-net shape production, high production rates, profitability, and improved material properties.
This document discusses the process of solidification in castings. It covers topics including the introduction to solidification, concepts of solidification in castings, solidification of pure metals and alloys, nucleation and growth. Specifically, it describes how solidification begins with the formation of nuclei near the mold walls and progresses through dendritic growth until the entire melt is crystallized. It also discusses solidification curves and phase diagrams for pure metals and alloys.
This document summarizes various surface treatment techniques including mechanical processes like shot peening and deep rolling that modify the surface without changing chemistry, thermal processes like electron beam treatment and laser treatment, and thermo-chemical processes like carburizing, nitriding, and carbonitriding that diffuse elements like carbon or nitrogen into the surface. It provides details on the mechanisms, advantages, and applications of these different surface modification methods.
This Presentation covers the basic concepts of Hot cracks and cold cracks in welding. For more information, please refer the books mentioned in the references slide.... Thank you
The objective of this subject is to develop a practical understanding of welding with regard to welding processes, and auxiliary welding equipment for the welder. Also, to develop a technical understanding of the information contained on engineering drawings and the use of the information to communicate setup and welding instructions from the designer to the welder and fitter.This subject is very important for engineering as well as diploma in Mechanical Engineering department students.I hope you will get some ideas about welding technology.
Welding process
Arc Welding
Resistance Welding
Oxy fuel Gas Welding
Other Fusion Welding Processes
Solid State Welding
Weld Quality
Weld ability
Design Considerations in Welding
The Heat-Affected Zone (HAZ) refers to the area of a material surrounding a weld that is altered by the heat of welding but not fully melted. During welding, this area experiences microstructural and property changes compared to the parent material due to elevated temperatures. These changes can include grain growth, reduced strength, and increased brittleness. As a result, failures often occur within the HAZ. The extent and properties of the HAZ depend on factors like material composition, welding process, heat input, and cooling rate. Proper welding parameters and techniques can minimize the size and negative impacts of the HAZ.
The document discusses different types of carbon and alloy steels. It begins with an introduction to carbon steels, outlining their classification and composition limits. It then discusses alloy steels, explaining that alloying elements are added to improve properties over plain carbon steel. Alloy steels are classified as low, medium, and high alloy steels. High alloy steels include stainless steels. The document explores various stainless steel types and how alloying elements affect their microstructure. In particular, it examines how elements can expand or contract the gamma phase field. Finally, it briefly discusses tool steels and their classification system.
Its a class lecture about Centrifugal Casting in Production Process subject. This class held at Khulna University of Engineering & Technology. Class conducted by Md. Abdullah Al Bari.
The document discusses various types of steel and factors that influence weldability. It covers the classification of plain carbon steels based on carbon content. It also discusses alloy steels and how elements like carbon, manganese, molybdenum, and chromium influence the properties of steel. The document further summarizes different types of cracks that can occur during welding like hydrogen cracking, solidification cracking, and lamellar tearing. It explains the factors that contribute to these cracks and measures to prevent them.
Patterns are models used to form cavities in molds for metal casting. There are different types of patterns based on their construction:
- Solid or one-piece patterns are made from a single piece for simple castings.
- Split patterns are made in two pieces for more complex shapes, with dowel pins to align the pieces.
- Loose-piece patterns have removable pieces to allow pattern withdrawal, connected by dowel pins.
- Match-plate patterns mount multiple split patterns on a plate, which is positioned between cope and drag molds.
Patterns are made larger than the intended casting to allow for material shrinkage and machining during production. Allowances are also made for draft,
The document discusses the CO2 casting process. In this process, CO2 gas is used to harden sand molds. When CO2 gas comes into contact with sodium silicate in the sand mixture, it forms a stiff gel that strengthens the mold. The CO2 is forced into the packed mold at pressure. This process produces dimensionally accurate castings with a fine surface finish more quickly than green sand casting. However, it is not as economical. The molds also cannot be easily reclaimed.
This document discusses the solidification of metals. It begins with an introduction to metals and their importance in dentistry. It then covers the classification of metals and their properties like conductivity. The document discusses the history of metals and how solidification occurs through nucleation and crystal growth below the melting point. It provides examples of solidification patterns in metals like steel and how properties like carbon content affect the patterns.
The document discusses two main forging processes: open die forging and closed die forging. Open die forging uses simple flat dies and is used for large or low volume parts. Closed die forging uses carefully machined matching dies to produce parts to close tolerances. The process involves preforming billets, rough forging in blocking dies, finishing in final dies, and trimming flash. Closed die forging produces parts with good dimensions and properties but requires high die costs for small volumes.
Metal forming processes are used to shape metals into useful products. Rolling is the most common forming process and accounts for around 90% of metal forming. It involves passing metal between rolls to reduce thickness or change cross-section. Forging uses dies and compression to shape hot or cold metal. Extrusion forces heated metal through a die to create shapes like rods, tubes and structural sections. Drawing pulls metal through a die to make wires, rods and tubes from both hot and cold workpieces. Deep drawing specifically makes cylindrical parts like cups from sheet metal.
Here is a heat treatment that could help determine the carbon content of the steel:
1. Reheat the steel to above its upper critical temperature to fully austenitize it.
2. Quickly quench it in oil or water to transform the austenite to martensite.
3. Measure the hardness of the resulting martensite. Higher carbon steels will have a higher hardness.
4. Compare the measured hardness to known hardness values for different carbon contents after a similar heat treatment. This could provide an estimate of the carbon content.
The idea is that the hardness of the martensite is dependent on the carbon content. By inducing a full martensitic transformation, the carbon content
Demand of welding increase of new materials.
-- ceramics and metal matrix composites.
-- High strength low-alloy (HSLA) steels
Lack of skilled labours
Traditional welding techniques are costly
Safety concerns.
Need to improve the total cost effectiveness of the welding
Lalit Yadav
This document provides information on various metal casting processes. It discusses the history of casting and defines the basic casting process as pouring liquid metal into a mold to solidify. It describes the main features of casting like molds, risers, gates, and cores. It categorizes casting processes as open mold or closed mold casting. It further classifies casting into expandable mold casting like sand casting and investment casting, and permanent mold casting like die casting and centrifugal casting. For each process, it provides details on the mold material, advantages, disadvantages and recommended applications. It emphasizes the importance of selecting the right casting process based on the alloy, shape, tolerance and cost requirements of the final part.
The document discusses different types of welding including butt welding, spot welding, carbon-arc welding, and metal arc welding. Butt welding involves clamping two metal pieces together face to face and applying a current through electrodes to reach melting temperature. Spot welding is commonly used to join sheets and can be operated by semi-skilled workers. Carbon-arc welding uses a carbon electrode and is suitable for non-ferrous metals. Metal arc welding produces an electrical arc between a consumable electrode and workpiece to fuse the metals together.
Electron beam welding uses a beam of electrons accelerated by high voltage to melt and join materials. It can achieve deep penetration with minimal heat input. It produces a clean, homogeneous weld in a vacuum environment without filler metals or shielding gas. However, it requires expensive equipment and a vacuum chamber. Laser beam welding uses a focused laser beam to melt materials. It has high travel speeds but requires precise part fit-up and tracking. Solid state welding joins materials without melting through processes like friction, diffusion, or ultrasonic welding. Plasma welding uses an arc struck in an externally-supplied ionized gas to produce high temperature for welding metals. Explosion welding joins materials through high velocity impact using a chemical explosion.
This document provides terminology related to welding codes and qualifications. It defines key terms like essential variables, non-essential variables, and supplementary variables. It also discusses welding terminology like weld beads, types of joints, and weld positions. The document is part of a larger guide on welding qualification simplified according to the ASME IX Code and covers topics like steel welding metallurgy, welding processes, weld symbols, and acceptance criteria for welds.
The document discusses various metal forming processes used to change the shape of metal workpieces through plastic deformation exceeding the metal's yield strength, including bulk deformation techniques like rolling, forging, and extrusion that involve significant shape changes with lower surface area to volume ratios, and sheet metalworking techniques like bending, drawing, and shearing that are performed on metal sheets or strips with higher surface area to volume ratios. Metal forming is an important manufacturing method that allows for net or near-net shape production, high production rates, profitability, and improved material properties.
This document discusses the process of solidification in castings. It covers topics including the introduction to solidification, concepts of solidification in castings, solidification of pure metals and alloys, nucleation and growth. Specifically, it describes how solidification begins with the formation of nuclei near the mold walls and progresses through dendritic growth until the entire melt is crystallized. It also discusses solidification curves and phase diagrams for pure metals and alloys.
This document summarizes various surface treatment techniques including mechanical processes like shot peening and deep rolling that modify the surface without changing chemistry, thermal processes like electron beam treatment and laser treatment, and thermo-chemical processes like carburizing, nitriding, and carbonitriding that diffuse elements like carbon or nitrogen into the surface. It provides details on the mechanisms, advantages, and applications of these different surface modification methods.
This Presentation covers the basic concepts of Hot cracks and cold cracks in welding. For more information, please refer the books mentioned in the references slide.... Thank you
The objective of this subject is to develop a practical understanding of welding with regard to welding processes, and auxiliary welding equipment for the welder. Also, to develop a technical understanding of the information contained on engineering drawings and the use of the information to communicate setup and welding instructions from the designer to the welder and fitter.This subject is very important for engineering as well as diploma in Mechanical Engineering department students.I hope you will get some ideas about welding technology.
Welding process
Arc Welding
Resistance Welding
Oxy fuel Gas Welding
Other Fusion Welding Processes
Solid State Welding
Weld Quality
Weld ability
Design Considerations in Welding
The Heat-Affected Zone (HAZ) refers to the area of a material surrounding a weld that is altered by the heat of welding but not fully melted. During welding, this area experiences microstructural and property changes compared to the parent material due to elevated temperatures. These changes can include grain growth, reduced strength, and increased brittleness. As a result, failures often occur within the HAZ. The extent and properties of the HAZ depend on factors like material composition, welding process, heat input, and cooling rate. Proper welding parameters and techniques can minimize the size and negative impacts of the HAZ.
The document discusses different types of carbon and alloy steels. It begins with an introduction to carbon steels, outlining their classification and composition limits. It then discusses alloy steels, explaining that alloying elements are added to improve properties over plain carbon steel. Alloy steels are classified as low, medium, and high alloy steels. High alloy steels include stainless steels. The document explores various stainless steel types and how alloying elements affect their microstructure. In particular, it examines how elements can expand or contract the gamma phase field. Finally, it briefly discusses tool steels and their classification system.
Its a class lecture about Centrifugal Casting in Production Process subject. This class held at Khulna University of Engineering & Technology. Class conducted by Md. Abdullah Al Bari.
The document discusses various types of steel and factors that influence weldability. It covers the classification of plain carbon steels based on carbon content. It also discusses alloy steels and how elements like carbon, manganese, molybdenum, and chromium influence the properties of steel. The document further summarizes different types of cracks that can occur during welding like hydrogen cracking, solidification cracking, and lamellar tearing. It explains the factors that contribute to these cracks and measures to prevent them.
Patterns are models used to form cavities in molds for metal casting. There are different types of patterns based on their construction:
- Solid or one-piece patterns are made from a single piece for simple castings.
- Split patterns are made in two pieces for more complex shapes, with dowel pins to align the pieces.
- Loose-piece patterns have removable pieces to allow pattern withdrawal, connected by dowel pins.
- Match-plate patterns mount multiple split patterns on a plate, which is positioned between cope and drag molds.
Patterns are made larger than the intended casting to allow for material shrinkage and machining during production. Allowances are also made for draft,
The document discusses the CO2 casting process. In this process, CO2 gas is used to harden sand molds. When CO2 gas comes into contact with sodium silicate in the sand mixture, it forms a stiff gel that strengthens the mold. The CO2 is forced into the packed mold at pressure. This process produces dimensionally accurate castings with a fine surface finish more quickly than green sand casting. However, it is not as economical. The molds also cannot be easily reclaimed.
This document discusses the solidification of metals. It begins with an introduction to metals and their importance in dentistry. It then covers the classification of metals and their properties like conductivity. The document discusses the history of metals and how solidification occurs through nucleation and crystal growth below the melting point. It provides examples of solidification patterns in metals like steel and how properties like carbon content affect the patterns.
The document discusses two main forging processes: open die forging and closed die forging. Open die forging uses simple flat dies and is used for large or low volume parts. Closed die forging uses carefully machined matching dies to produce parts to close tolerances. The process involves preforming billets, rough forging in blocking dies, finishing in final dies, and trimming flash. Closed die forging produces parts with good dimensions and properties but requires high die costs for small volumes.
Metal forming processes are used to shape metals into useful products. Rolling is the most common forming process and accounts for around 90% of metal forming. It involves passing metal between rolls to reduce thickness or change cross-section. Forging uses dies and compression to shape hot or cold metal. Extrusion forces heated metal through a die to create shapes like rods, tubes and structural sections. Drawing pulls metal through a die to make wires, rods and tubes from both hot and cold workpieces. Deep drawing specifically makes cylindrical parts like cups from sheet metal.
Here is a heat treatment that could help determine the carbon content of the steel:
1. Reheat the steel to above its upper critical temperature to fully austenitize it.
2. Quickly quench it in oil or water to transform the austenite to martensite.
3. Measure the hardness of the resulting martensite. Higher carbon steels will have a higher hardness.
4. Compare the measured hardness to known hardness values for different carbon contents after a similar heat treatment. This could provide an estimate of the carbon content.
The idea is that the hardness of the martensite is dependent on the carbon content. By inducing a full martensitic transformation, the carbon content
Demand of welding increase of new materials.
-- ceramics and metal matrix composites.
-- High strength low-alloy (HSLA) steels
Lack of skilled labours
Traditional welding techniques are costly
Safety concerns.
Need to improve the total cost effectiveness of the welding
Lalit Yadav
This document provides information on various metal casting processes. It discusses the history of casting and defines the basic casting process as pouring liquid metal into a mold to solidify. It describes the main features of casting like molds, risers, gates, and cores. It categorizes casting processes as open mold or closed mold casting. It further classifies casting into expandable mold casting like sand casting and investment casting, and permanent mold casting like die casting and centrifugal casting. For each process, it provides details on the mold material, advantages, disadvantages and recommended applications. It emphasizes the importance of selecting the right casting process based on the alloy, shape, tolerance and cost requirements of the final part.
The document discusses different types of welding including butt welding, spot welding, carbon-arc welding, and metal arc welding. Butt welding involves clamping two metal pieces together face to face and applying a current through electrodes to reach melting temperature. Spot welding is commonly used to join sheets and can be operated by semi-skilled workers. Carbon-arc welding uses a carbon electrode and is suitable for non-ferrous metals. Metal arc welding produces an electrical arc between a consumable electrode and workpiece to fuse the metals together.
Electron beam welding uses a beam of electrons accelerated by high voltage to melt and join materials. It can achieve deep penetration with minimal heat input. It produces a clean, homogeneous weld in a vacuum environment without filler metals or shielding gas. However, it requires expensive equipment and a vacuum chamber. Laser beam welding uses a focused laser beam to melt materials. It has high travel speeds but requires precise part fit-up and tracking. Solid state welding joins materials without melting through processes like friction, diffusion, or ultrasonic welding. Plasma welding uses an arc struck in an externally-supplied ionized gas to produce high temperature for welding metals. Explosion welding joins materials through high velocity impact using a chemical explosion.
Electron beam welding uses a beam of electrons accelerated by high voltage to melt and join materials. It can achieve deep penetration with minimal heat input. It produces a clean, homogeneous weld in a vacuum environment without filler metals or shielding gas. However, it requires expensive equipment and a vacuum chamber. Laser beam welding uses a focused laser beam to melt materials. It has high travel speeds but requires precise part fit-up and positioning. Solid state welding joins materials without melting through processes like friction, diffusion, or ultrasonic welding. This reduces heat effects but is limited in applications. Plasma welding uses an arc struck in an externally-supplied ionized gas to produce high temperature for welding metals.
This document provides an overview of various joining processes, including fusion welding processes like gas welding, arc welding, TIG welding, MIG welding, plasma arc welding, and electron beam welding. It also discusses solid-state welding processes and resistance welding processes like spot welding and seam welding. Specific details are provided on plasma arc welding and resistance welding, including their principles, advantages, and applications.
The document discusses various special welding techniques including resistance welding processes like spot welding, seam welding, and butt welding. It provides details on the principles, fundamentals, equipment, and operation of resistance spot welding which involves melting metal at the contact point between two overlapping workpieces using heat generated by an electric current. The current passes through electrodes that also apply pressure to complete the weld. Seam welding produces a continuous weld along a joint using mechanically driven roller electrodes. Butt welding involves heating and forging together the ends of two abutting workpieces.
The document provides information on transformer design specifications and considerations. It discusses technical specifications for a 500KVA, 3 phase transformer including input/output voltages and power ratings. It also covers initial calculations, losses in transformers, core materials and construction, winding design, insulation, cooling methods, and connection configurations. The goal is to design a transformer that efficiently transfers power while meeting specifications for voltage, current, temperature rise and other factors.
Gas Metal Arc Welding or MIG welding .
Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a welding process in which an electric arc forms between a consumable wire electrode and the workpiece metal(s), which heats the workpiece metal(s), causing them to melt and join
pulsed spray
globular spray
Welding is a process that joins materials by causing fusion and filling the joint with a filler material. There are several advantages to welding including lighter structures, maximum strength in joints, easy alterations, pleasing appearance, and strength equal to the parent material. Spot welding uses two electrodes to locally fuse materials and is commonly used in automotive and aircraft industries to join sheet metal. MIG welding uses an inert gas shield to prevent contamination and is often used for carbon/alloy steels, stainless steel, aluminum and other metals due to its high welding speed and economy. Common welding defects include lack of penetration, undercut, slag inclusion, porosity, cracks, spatter, and distortion.
Manual metal arc welding is a versatile fusion welding process where the heat is provided by an electric arc between the electrode and the workpiece. Key factors that affect the weld quality include amperage, voltage, travel speed, and polarity. Other arc welding processes discussed include MIG/MAG welding using a continuously fed wire electrode and an inert or active gas shield, TIG welding using a non-consumable tungsten electrode and separate filler rod with an inert gas shield, and submerged arc welding where the arc and weld pool are shielded by a blanket of fusible flux.
This document discusses metal inert gas (MIG) and tungsten inert gas (TIG) welding processes. It describes the key equipment, parameters and transfer methods used in MIG welding like globular, short circuiting, spray and pulsed spray. It also outlines the advantages of MIG welding as being a high deposition rate process with no slag and versatility. Limitations mentioned are irregular wire feed and burn back. For TIG welding, it explains that a tungsten electrode is used with an inert gas shield and filler metal can be added. TIG provides high quality welds needed for precision industries and can be mechanized easily.
This document provides information on various welding processes including resistance welding, spot welding, seam welding, projection welding, percussion welding, thermit welding, friction welding, explosive welding, ultrasonic welding, and diffusion welding. It explains the basic principles, equipment, and applications of each process. Resistance welding generates heat through resistance to electric current and is commonly used for sheet metal. Spot welding uses electrodes to create overlapping welds. Seam welding produces a continuous air-tight seam.
Electrical discharge machining (EDM) involves using electrical sparks to erode metal surfaces. Key aspects include:
1) An electrode is used to shape electrical discharges that melt and vaporize small amounts of material from the workpiece. Common electrode materials include copper, tungsten, and graphite.
2) A dielectric fluid is used to separate the electrode and workpiece and to flush away debris. Typical fluids include oil-based fluids like kerosene.
3) An electrical charge creates sparks that momentarily melt and vaporize metal. Process parameters like voltage, gap size, and flush rate must be optimized to control the erosion process.
This document discusses resistance welding, specifically spot welding and seam welding. It explains that resistance welding uses electrical current to generate heat and join metal pieces. For spot welding, current is applied through electrode tips that hold the metals under pressure. Spot welding is used extensively in automotive and aerospace industries. Seam welding is a continuous version of spot welding that produces leak-proof seams, such as for fuel tanks, by overlapping spot welds. Key factors in resistance welding include current, time, pressure, and electrode material and design.
The document provides information on various welding processes including submerged arc welding, hyperbaric welding, and stud welding. Submerged arc welding involves an electric arc formed between an electrode and workpiece under a covering layer of flux. It allows for high deposition rates and quality welds. Hyperbaric welding is performed inside a pressurized chamber and allows for underwater welding. Stud welding uses an electric arc to instantly weld metal stud fasteners to workpieces for permanent bonding.
Arc welding is type of welding in Manufacturing Processes. Brief Introduction about Arc welding and types of arc welding and their introduction. There are many types of Arc welding available in the market.
This document discusses the electrical properties and factors affecting the resistance of conducting materials. It describes how resistance increases with temperature, thickness, and certain alloys. Common conducting materials like copper, brass, and bronze are discussed due to their high conductivity. Materials with higher resistivity like nickel and alloys are also summarized for applications requiring greater resistance like heating elements. Classification of materials into low and high resistivity types is covered along with their suitable applications based on properties.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, Serbia
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Embedded machine learning-based road conditions and driving behavior monitoring
High frequency welding
1. High Frequency Welding
Prepared by: - Darshan Shah
Smit Solanki
M.E. Welding Technology (2018-19)
Metallurgical & Materials Engineering Department,
The Maharaja Sayajirao University of Baroda
2. High Frequency Welding
• High-frequency welding is included in
a group of resistance welding process
variations that use high-frequency
welding current (1kHz to 800kHz) to
concentrate the welding heat at the
desired location.
• The heat produces the coalescence of
metals, and an upsetting force usually
is applied to produce a forged weld.
• High-frequency resistance welding is
an automated process and is not
adaptable to manual welding.
2
3. High Frequency Welding
• High-frequency resistance welding was developed during the late 1940s and
early 1950s to fill the need for high-integrity butt joints and seam welds in pipe
and tubing.
• But today the process is also used in the manufacture of products such as spiral-
fin boiler tubes, closed roll form shapes, and welded structural beams.
• A wide range of commonly used metals can be welded, including low-carbon and
alloy steels, ferritic and austenitic stainless steels, and many aluminum, copper,
titanium, and nickel alloys.
• HFW is based on two main electrical phenomena
1. Skin effect
2. Proximity effect
3
4. DC
1. Skin effect
• High-frequency current in metal conductors tends to flow at the surface of the
metal at a relatively shallow depth, which becomes shallower as the electrical
frequency of the power source is increased. This effect is called the skin effect.
• Current penetration depth in a conductor as a function of frequency.
• Due to skin effect heating is concentrated on the surface of the conductor.
Where, δ = Current penetration depth
ρ = Resistivity of the conductor
ω = Angular frequency of current
μ = Magnetic permeability of the conductor
4
5. 2. Proximity effect
• When two conductors carrying HF current are placed close to one another, the current
concentrates on the two adjacent surfaces of the conductors. This is called the proximity
effect.
• Two currents flowing in opposite directions on the same material are mutually attracted.
• Due to proximity effect the heating is concentrated on very little part of the surface of the
conductor.
5
8. High Frequency Induction Welding
• The induction coil induces a circumferential current in the tube.
• The high-frequency current flows along the edge of the weld vee due to the
proximity effect, and the edges are resistance heated to a shallow depth due to the
skin effect.
• Vee length usually between 1.5 to 2 tube diameter.
• Vee angle generally is between 3° and 7°.
• The welding speed and power source level are so adjusted that the two edges are
at the welding or forge temperature when they reach the weld point.
• The forge rolls press the hot edges together, applying an upset force to complete
the weld.
• Hot metal containing impurities from the faying surfaces of the joint is squeezed
out of the weld in both directions, inside and outside the tube.
• The upset metal normally is trimmed off flush with the base metal.
• One of the advantage of using HF is that it minimize the number of turns of
induction coil to 1 – 3 turns.
8
9. Impeder
Inside the
Core
Promotes
Path ADC
Why impeder is needed?
• Due to skin effect the HF current is
flowing from the very thin layer of the
surface.
• So it distinguishes the outside layer and
inside layer of the tube as two different
conductor.
• Here middle layer of the tube acts as a
perfect insulator as no current is passing
through it due to skin effect.
• The purpose of the impeder is to increase
the impedance (inductive reactance or
effective resistance) of the current path
around the inside wall of the workpiece.
This reduces the current that would
otherwise flow around the inside of the
tube and cause an unacceptable loss of
efficiency.
• An impeder is made from a magnetic
material such as ferrite.
9
10. High Frequency Contact Welding
• The process essentially is the same as
induction welding.
• The major difference is that sliding
contacts are placed on the tube
adjacent to the unwelded edges at the
vee length.
• Generally vee length is shorter than that
used with the induction process
because the pressure rolls are not
inductively heated by the magnetic field
of the induction coil.
• So the sliding contact can be placed
within the confine space.
10
12. Comparison of the Induction and Contact
Welding Process
• Contact welding is a more efficient process than induction welding
because of the shorter vee length and because there are no losses in the
induction coil.
• For the seam welding of large-diameter pipe, the contact process can use as little
as half the power required by the induction process.
• The major disadvantage of the contact process is sliding contact wear.
• The service life of the contact tips decreases with increasing welding power level
so generally it is not operated above 800 kW.
• In contact welding process under some conditions, arcing between the
sliding contacts and the tube can occur. This may cause “arc marks”.
• Arc marks are required to be removed by a subsequent grinding operation.
• Generally induction welding can be used to weld the smaller-diameter
tube sizes, and contact welding can be used to weld the larger-diameters
sizes.
12
13. Welding Fins to Boiler Tube
• In Circumferential Fin Welding,
the fin is helically wound on
edge around a tube and
simultaneously welded to the
surface of the tube.
• In Longitudinal Fin Welding,
Fins can be welded
longitudinally to a tube on one
or both sides.
• This type of tube is used to
manufacture water walls in
boilers.
• Tube also can be welded to strip
or sheet metal for products
such as solar absorber plates
and freezer.
13
Weld
Weld
14. Contact Welding of Structural Beams
• Continuous high frequency
contact welding can be
adapted for the fabrication of
structural I-beams, T-beams
and H-beams.
• It is just a slight modification
to the fin welding technique
14
Weld
15. Seam Welding of Closed Roll Form Shapes
• Contact or induction processes can be
used depending on C/S.
• Lap welds are often made in roll form
components.
• lap joints must be designed with
consideration for the proximity effect,
and the two faying surfaces must be
brought together to form a vee.
• The geometry of the workpiece often
complicates the forge roll design.
15
Projecti
on Seam
Weld
Roll
Formed
Beam
16. Induction Welding of Pipe Butt Joints
• Closer the proximity conductor
develops a more confined current path.
• If a magnetic core is placed around the
proximity conductor, the current would
be further concentrated and heating
would take place directly below the
proximity conductor.
• High-frequency current in the coil
induces a circulating current
concentrated in the area of the pipe
butt joint, which is heated very rapidly.
• When the metal reaches welding
temperature, upset force is applied to
produce a forge weld.
16
17. Contact Welding of Finite-Length Plate Butt
Joints
• Same or dissimilar metals
• Can be of different thicknesses
• Low frequencies between 1 kHz and 10 kHz
generally are used.
• The current is introduced at each end of the
joint by small contacts and is confined to the
area of the joint by a proximity conductor.
• Magnetic core is used to assist in narrowing
the current path.
• When the joint reaches the welding
temperature, a forging force is applied and
the hot metal is upset.
• Welds of this type can be made at rates up to
1000 joints per hour.
17
20. Welding Equipments
• Equipment for high-frequency resistance welding includes
1. Power source (usually a solid-state inverter type)
2. Induction coils
3. Contacts
4. Impeders
5. Control devices
6. Mechanical equipment for
preparing and aligning
the workpieces.
20
21. Power source
• The predominant power source in modern installations of high-
frequency welding equipment is the solid-state inverter power source.
• These units provide welding output power ranging from 50 kW to 1800
kW and operate at frequencies from 80 kHz to 800 kHz.
• Solid-state power sources are smaller in size than traditional vacuum-
tube units and typically demonstrate efficiencies over 80%, while
vacuum-tube units operate at efficiencies between 50% and 65%.
• Economically efficient operation results in a significant decrease in
power consumption and cooling-water requirements.
21
24. Induction Coils
• It is generally fabricated from copper tubing, hollow copper bar or copper sheet.
• Normally water cooled
• Highest efficiency is obtained when the induction coil completely surrounds the
workpiece.
• Coil may have one or more turns.
• The strength of the magnetic field reduces rapidly as the distance between the
coil and the workpiece is increased.
• Spacing between the coil and the workpiece ranges from 3 mm for small-
diameter products to up to 25 mm for large-diameter products
24
25. AWS Welding Handbook
Contacts
• Made of copper alloy or may be
composed of hard metallic or ceramic
particles in a copper or silver matrix.
• Contact tips are hold via mounts.
• Replaceable due to wear.
• Internal and external cooling is required
for the contact tip and mounts.
• Area of contact tip = 0.25 - 1 in2
• Welding current = 500 - 5000 Amps
• Force of the contact tip against the
workpiece ranges between 20 – 200 N
• Service Life
• 1000 feet under very severe conditions
• 3,00,000 feet if circumstances are
optimal
25
26. Impeders
26
• The primary function of an impeder is to increase
the impedance around the inside circumference
of the tube, thus diverting more energy into the
weld “vee”.
• An impeder is made from a magnetic material
such as ferrite.
• The impeder must be cooled to prevent its
temperature from rising above its Curie
temperature, where it becomes nonmagnetic.
(For ferrite, it is between 170°C and 340°C.)
• The impeder is positioned so that it extends
about 1.5 mm to 3 mm beyond the apex of the
vee and the equivalent of 1 to 2 workpiece
diameters upstream of the induction coil.
27. Control Devices
• Control Devices maintain proper welding conditions at different mill
speeds.
• Especially to minimize scrap material resulting when the mill is started
and stopped, the weld power can be automatically adjusted as a
function of mill speed by control Devices.
• So it can virtually eliminate any unwelded seam when the mill is stopped
and restarted.
• The system also will reduce scrap.
• Weld temperature control system reads the output of a pyrometer or
analyzes the image obtained by an infrared camera aimed at the weld
vee, and automatically adjusts the welding power to maintain a
constant, preset temperature.
27
28. Advantages of High-Frequency Welding
• Produce welds with very narrow heat-affected zones (HAZ) so often
postweld heat treatment is eliminated.
• High welding speed and low-power consumption
• Able to weld very thin wall tubes
• A wide range of commonly used metals can be welded.
• Minimize oxidation and discoloration as well as distortion of workpiece
• Flux is almost never used but inert gas shielding is can be used for joining
highly reactive metals such as titanium
• High efficiency
28
29. Limitations of High-Frequency Welding
• As the equipment operates in the radio frequency range, special care
must be taken to avoid radiation interference in the plant’s vicinity
• Special precautions must be taken to protect the operator and plant
personnel from the hazards of high-frequency current.
• Uneconomical for products required in small quantities
• Need of proper fit-up for the surfaces to be joined
29
30. Some Products of High-Frequency Welding
30[Reference: Welding Handbook, Volume 2, p.665, AWS]
31. References
1. AWS Handbook, Volume 3 - Welding Processes, Part 2
2. John Wright , “Principles of high frequency induction tube welding”
3. Ilona Iatcheva, Georgi Gigov, Georgi Kunov, Rumena Stancheva, “Analysis of induction
heating system for high frequency welding,” Facta Universitatis, Ser: Elec. Energ. Vol. 25,
No 3, December 2012, pp. 183 - 191 DOI: 10.2298/FUEE1203183I
4. John Wright , “Optimizing Efficiency in HF Tube Welding Processes”
5. H. HAGA, K. AOKI AND T. SATO, “Welding Phenomena and Welding Mechanisms in High
Frequency Electric Resistance Welding—1st Report,” AWS 60th Annual Meeting held in
Detroit, Michigan, during April 2-6, 1979
6. Yan Pei, “High Frequency Induction Welding & Post-Welding Heat Treatment of Steel
Pipes,” University of Cambridge, June 2011
7. A. SPAHIU, “Experimental study of the induction heating in the manufacturing of
metallic tubes by longitudinal welding process,” U.P.B. Sci. Bull., Series C, Vol. 69, No. 2,
2007
8. OKABE Takatoshi, IIZUKA Yukinori, IGI Satoshi, “High Reliability Technology of the Weld
Zone of High-Frequency Electric Resistance Welding Linepipes,” FE GIHO No. 34 (Aug.
2014), p. 77–83
31