welding

Welding

The welding’s types, applications, and invention

Welding Definition

Welding is a process of union between two or more parts of materials, where it is United using heat/pressure or both.

A process whereby two or more parts are connected through heat/pressure or both. It is used to weld all types of metals, thermoplastics, etc.

Preface

Before proceeding let’s have a look, at a brief history of welding.

Welding devolved with the needs of human civilization and became popular as an art. With the development of human society, this technology also intensified and took the form of modern science.

The use of welding has become widespread in today’s technology. Various types of portable equipment and welding machines are available and make the welding work more productive and cost-effective.

Welding invention at a glance  

Welding technology has seen unprecedented growth since about 1930. Which continued to grow with the development of new technologies and industries.

The method of joining metals together began around 4000 BC, in Egypt and its surrounding areas. It started with copper and then expanded into bronze, silver, gold, and iron. Since copper was found as an ore at that time, its use was limited to only domestic use items and hunting weapons. Welding technology has seen phenomenal growth since about 1930.

  • Forge and pressure welding come first in welding techniques when metals are joined by hammering or pressing.
  • Another revolution occurred in 1895 when a French chemist, Henri Louis Le Chatelier, showed that the combustion of acetylene with oxygen produced a flame, initiating the discovery of the oxy-acetylene process.

Although the commercial success of the oxyacetylene process was dependent on the availability of oxygen, a practical type of torch was introduced in the early 1900s, and by 1903 the oxyacetylene process was used industrially.

  • The electric arc was discovered by Davy in the early eighteenth century (1809) in England, which went through various stages for the next 50 years, eventually leading to the introduction of arc welding in electric dynamos and generators between 1877 and 1880.

Some important inventions in this phase are as follows:

  • 1877-1880 -improvements in electric dynamos or generators.
  • 1881 -Auguste de Meritcns established the arc welding process, which was applied to join certain components of electrical storage batteries. The joining of metals using the carbon arc was suggested by Moisson (a Frenchman)
  • 1885-1887 -Bernardos and Olszewski used single carbon arc welding for joining metals in Russia and got patented.
  • 1889 – Zerener processed an idea, to develop Twin Carbon arc welding.
  • 1892 -N.G. Slavianoff proposed the use of bare wire metallic electrodes for joining metals in Germany.
  • 1907 -Oscar Kjellberg got a patent for covered electrodes, which contained only arc stabilizing materials.
  • 1912 – Strohmenger (USA) obtained another patent on covered electrodes for the first good welded joint. He used a coating of blue asbestos with sodium silicate as a binder.
  • 1919 -The American Welding Society (AWS) was founded
  • 1928 -Arc and molten pool shielding with an inert gas (C02) were invented by Alexander in the United States.
  • 1921 -Atomic hydrogen welding was developed on the basis of the research carried out by Langmuirin in the United States.
  • 1929 -The covered electrode was commercialized.
  • 1930 -Hobart and Devers got painted for TIG welding in the United States.
  • 1946 -First gas tungsten arc spot welding torch based upon TIG welding was introduced.
  • 1948 -(MIG) welding was developed.
  • 1935 -Kennedy, Rodermund, and Jones invented submerged arc welding in the United States
  • 1938 -Nelsen rediscovered Stud welding which was founded by Martin in 1918 and was used in the British(Royal) Navy.
  • 1953 –Electroslag welding appeared in Russia. Plasma arc welding was developed in the U.S.A.
  • 1955-1960 Plasma cutting was developed and started to use respectively.
  • 1886 -Professor Elihu Thomson demonstrate the possibility of joining metals by resistance welding at Franklin Institute in Philadelphia.

Resources: [AWS org] ,[wikipedia.org] [Weldtech]

Types of welding 

At present, welding has made a place in industries as well as in common life with its various forms. The main types of welding are as follows

  • Arc Welding
  • Gas welding
  • Resistance Welding 
  • Solid-State Welding Process
  • Thermo-Chemical Process
  • Radiant Energy Process

Welding Joint design

Welding joint design refers to the technique of aligning metal pieces together or aligning them with each other.

Welding Joint design
welding joint design

Welding Joint Types

A welding joint is designed to join metal parts firmly and smoothly. a weld joint may vary in different conditions. There are five main types of welding joints used for joining pieces of metals together.

  • Butt joint welding
  • Tee joint welding
  • Corner joint welding
  • Lap joint welding
  • Edge joint welding

Commonly Welded Base Metals

The metals to be welded can be classified as follows:

  • Ferrous
  • Non-ferrous

Ferrous materials

Iron is the main element in Ferrous material, Wherein the other ingredients are used as per the requirement. Iron material is the most important metal/alloy in the mechanical industry, and is used in most applications. The following are examples of ferrous materials.

  1. Wrought Iron
  2. Cast Iron.
  3. Carbon Steel (Low, Medium, and High Carbon Steels).
  4. Alloy Steels.
  5. Cast Steels.
  6. Stainless Steels, etc.

Non-ferrous materials

Non-ferrous materials are those that are not based on iron. Like ferrous material, non-ferrous material also has widespread industrial applications. The following are non-ferrous material examples:-

  • Aluminum and its alloys.
  •  Copper and its alloys.
  •  Magnesium and its alloys.
  •  Nickel and its alloys.
  • Zinc and its alloys, etc.

Welding equivalent

In modern times, the technology of joining metals has been dramatically improved by identifying the mechanical properties of materials and manufacturing filler metals corresponding to them.

The method of joining metals and thermoplastics is now being widely used instead of welding by various other means. Apart from welding techniques, other options for joining metals mainly include riveting, brazing, etc.

Further Details>>> Welding as compared to riveting

Practical applications of welding

Welding technology is widely used today. Regular manufacturing of automobiles, cars, air-crafts, refrigerators, etc. by means of welding, repair, and maintenance work, such as repair of broken parts, and rebuilding of worn-out components, are the main uses.

The common applications are listed below:

  • Aircraft Construction  Welded engine mounts, turbine frame for a jet engine, rocket motor fuel, and oxidizer tanks, ducts, fittings, cowling, components, etc.
  • Automobile Construction Arc welded car wheels, steel rear axle housing, frame side rails. automobile frame brackets, etc.
  • Bridges Pier construction, Shop and field assembly of lengths, etc.Section lengths.
  •   Buildings Column base plates, trusses, Erections of structure, etc.
  • Pressure vessels and Tanks Clad and Lined steel plates, shell construction joining of the nozzle to the shell, etc.
  • Storage Tanks Oil gas and water storage tank
  • Rail Road Equipment Locomotive, Underframe, air receiver, engine.Front and rear hoods, etc.Front and rear hoods, etc.
  • Pipings and pipelines Rolled plate piping, open pipe joints, oil, gas, and gasoline pipelines, etc.
  • Ships Shell frame, deck beams, and bulkhead stiffeners. girders to shells.Bulkhead webs to plating, etc.

Other useful applications are Trucks and trailers. Machine tool frames, cutting tools, and dies.Household and office furniture.Earthmoving machinery and cranes.

Advantages and limitations of welding

Although welding is a great option for joining metal parts or thermoplastics, it also has some limitations and flaws that will be discussed briefly here.

Advantages of welding 

  • Ideal welding is strong and durable as the base metal.
  • Usually, the equipment used in the general welding process is not expensive and available almost everywhere.
  • Equipment used in most welding processes is available in portable versions, making it easy to perform on-site welding.
  •  The facility of welding on site is possible.
  •  The advent of portable welding machines has reduced the welding cast.
  • The discovery of new welding techniques and metallurgy research have made it possible to weld a large number of metals/alloys, both similar and dissimilar.
  • Metals are now also be joined by mechanized, through welding automation.

Disadvantages of welding 

  • Harmful radiation (light) emitted during the welding process can harm the eyes, 
  • The welding electrodes emit toxic fumes and splashes that affect the lungs and skin. Proper protection is required to avoid this.
  • Welding joint edge preparation is required, before starting the welding operation.
  • A skilled welder is needed for a good welding result.
  • Residual stress and distortion can occur in a workpiece.

Best welding practices

Usually, welding produces ultra-violet rays and toxic fumes that are extremely harmful to human health. This can be avoided by following some necessary safety measures.

A welder can protect himself by following some best welding practices, such as:

  • Always check the surroundings for any flammable materials such as dry wood, paper, gasoline, oil, grease, paint or chemicals, etc. Keep these elements, away from the area, if not possible, cover it with a fire blanket
  • Always check the machine and tools before starting work. If there is any defect, do not use it as it can cause some danger
  • The machine should be grounded. If the current leaks from somewhere, then it should be grounded directly, this avoids the risk of getting a herb.
  • Always use a proper helmet including (black shaded glass) to protect your eyes from ultraviolet rays.
  • Use a proper mask to avoid inhaling toxic gases.
  • Use appropriate hand gloves, sleeves, and aprons for protecting body parts from heating/burning or shocking risks.

                Further details >>> Safety recommendations in the welding operation

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