Terms and Definitions Reminder about Welding:

Automatic Welding is performed with automatic equipment that requires no controls adjustment by an operator.

Braze is the joint resulting by heating an assembly to the brazing temperature using a filler metal whose liquidus is higher than 450 0C (840 0F) and lower than the solidus of the base metal.

Double Welded Joint is a fusion welded joint that is welded from both sides of its thickness.

Friction-surfacing, a modification of friction welding, is a solid state process whereby layers of various metals are deposited upon a metallic substrate.

Gas Cylinder is a portable container used to store and transport compressed gas.

Hot Pressure Welding is a solid state welding process that produces a weld by application of heat and pressure sufficient to cause macro deformation of the base metal.

Reduced Section Tension Test is performed on a specimen where, in the middle of its reduced section, is located a transverse section of the weld.

Thermite Welding is a process that realizes joining of two parts by fusing them together with heat and filler metal given off by superheated molten metal from exothermic reactions, poured in a mold assembled around the joint.

How does Peak current and Base current affect the properties of weldments?

The current levels are only two of the parameters determining weld quality. To understand parameters function, the period can be broken down into several parts:

1. Ramp up rate increase stiffens the arc, reducing the arc column size and increasing the propelling force throwing molten drops detached from the electrode,
2. Overshoot, an instantaneous current increase above the peak current level, necessary to overcome the influence of inductance, variable with cable length,
3. Peak current level directly controls penetration: the higher the peak current, the deeper the penetration,
4. Peak Time or Peak Duration influences the width of the bead shape,
5. Tail-out drop time, speed of change and shape controls energy addition to the molten droplet, directly influencing puddle fluidity and penetration,
6. Sudden current drop down to background level, reduces the tendency for fine droplet spatter,
7. Background Current, the low-level current needed to maintain the arc,
8. Frequency or Repetition Rate shapes the weld bead by narrowing the arc cone with increased frequency.

Arc welding process and its equipments

Welding is regularly used for the permutation processes i.e. arc, resistance, laser, electron beam, stud and orbital welding.

Weld controllers are necessary to help the processes used by these tools. Welding equipments also work as aid to welding control source. There are also wide-ranging system to cutting machine, torch, feeders, cables, robots and feeders.

Arc welding process and welding machines

Arc welding is utilizing welding power supply to produce an electric arc between the base material and an electrode, for melting the metals at welding point. Arc welding equipments can use and direct current or alternating current, and consumable or non-consumable electrodes. Shielding gas guards welding region using some inert or semi-inert gas and evaporate wadding material. The process of arc welding is broadly known for low capital and running costs.

MIG and TIG welding are the two common specifications of Arc Welding. MIG is also acronym as MAG (metal active gas welding) and known as one of the mostly popular arc welding process. MIG welding equipments uses in different kinds of gas like pure carbon dioxide, argon gas and some time merge of both to complete the process.

Highlights On Mig Welding

Feed welding is the other popular name for Mig (Metal insert gas) welding. Other popular names for this weld technique in weld industry are like Gas Metal Arc Welding (GMAW or Metal Active Gas (MAG). It is one of the fastest and simplest techniques of weld.

The method of welding is semi-automatic or automatic. With the helping of welding gun wire electrode and a shielding gas is fed into it continuously. Apart from this Argon gas is also conceded in welding gun along with the wire electrode. This is done so as to achieve the desired results. This technique is mostly employed in high production and welding operations.

MIG welding operation can be carried on metals such as stainless steel, copper, carbon steel, and aluminum. All these metals can be weld in this process and moreover it can be performed in every position with the help of shielding gas, electrode, and welding conditions. This weld technique is popular in automobile industries. The gas which is fed in it acts as a shield agent protecting the weld zones from the contaminants of air borne. While performing this weld operation welder has to follow safety tips to protect him and others too.

How to use Electrodes in Welding Process

Electrodes are used in welding to transmit electrical energy to the metal that requests to be welded. Welding electrodes have change since the process of welding was industrial with carbon arc welding, but different other evolutionary processes, the former electrode types are still in use today.

Carbon Electrodes
Welding in progress with the carbon arc electrodes. Carbon electrodes are detained in a stinger and are the softest kind of welding electrode. This has difficulty that has ended carbon electrodes the least common type of electrode used today. The yielding make-up of carbon electrodes leads to weld contamination and a high use rate.

Resistance Electrodes
Resistance welding spot welding uses two copper electrodes and no inert gas to combine metals jointly. Copper electrodes are yielding, other than last longer then carbon electrodes. With each resistance weld a small quantity of the copper electrode is put down on the work piece.

Stick Welding
Stick welding electrodes are containing two components. The center rod conducts the electricity to the weld exterior, but dissimilar other electrodes, the interior rod are the filler rod used to fill the weld gap. The center filler rod/electrode is bounded by a hard outer coating, when the stick electrode is heated the hard coating melts and seals the weld from contamination.

Tungsten electrodes
Tungsten electrodes are the hardest of all welding electrodes and this categorize them as a non-consumable. Little or no tungsten electrode is set down into the weld, except by welder error. The hard nature of tungsten is used to its fullest benefit in TIG welding.

Tungsten inert gas (TIG) welding has a fast heat cycle and is used in state of affairs that require a solid sealed weld.

History of Waterjet Cutting

Waterjet cutting can be traced back to hydraulic mining of coal in the Soviet Union and New Zealand. Water was collected from streams and aimed to wash over a blasted rock face carrying away the loose coal and rock. Th is method of mining was redeveloped in South African gold mines to remove blasted rock from the work area into a collection drift or tunnel. In the California Gold Country between 1853-1886, pressurized water was first used to excavate soft gold rock from the mining surfaces. The pressurized water allowed the miner to stand further back from the face being washed. This was safer because there was less danger of being covered by a collapsing wall of blasted rock. By early 1900s this method of mining had re ached Prussia and Russia. In these two countries the pressurized water was used to wash blasted coal away.

In the 1930s it was Russia that made the first attempt at actually cutting the rock with the pressurized water. A water cannon was used to generate a pressure of 7000 Bars.

In the 1970s technology was developed in the USA that was capable of creating a 40,000 Bar pressure. Most of the waterjet mining growth after this involved combining a drill with the waterjet. In 1972 Professor Norman Franz of Michigan worked with McCartney Manufacturing Company to install the first industrial waterjet cutter. The equipment was installed in Alton Boxboard. Flow industries also began to market industrial waterjet cutting equipment. It was Flow Industries who added sand to a pressurized cleaning system to give metal a white finish. After this it was demonstrated that abrasive waterjet systems could cut through metal and ceramics. From here the waterjet cutting industry took off.

How TiG welding procedures are used for Mild steel

Mild steel is a steel alloy to facilitate has a low percentage of carbon, normally 0.3 percent or less. For this basis, mild steel is also called low-carbon steel. It is enormously common in manufacture because it is inexpensive compare with other steel alloys and is simple to weld. Mild steel can be welded with tungsten inert gas (TIG) welding methods, and the result is a clean and precise weld.

For the reason that the TIG welding process uses a tungsten electrode that is not consumed, a divide welding rod or wire is used as filler material for welding mild steel.

Steel require a sharper electrode point to concentrate the heat at the weld seam, as different to aluminum and other metals, in which heat dissipate more rapidly. The diameter of the electrode should be approximately half the thickness of the parts to be welded. The welding machine must be set for DC current and directly polarity, through the electrode having the negative charge.

General view about Tungsten Electrode

Electrodes are generally accessible in pure tungsten or tungsten with oxide additions of thorium, zirconium, and lanthanum.

Oxide additions decrease the electron emission energy of the electrode:

• pure tungsten (5.36 eV)

• thoriated tungsten (2.62 eV)

For AC welding pure tungsten or zirconiated tungsten are used, whereas for DC welding thoriated tungsten or tungsten electrodes with rare earth oxide additions are optional (thorium is radioactive).

Thoriated electrodes are not optional for AC welding; since the electrode tip does not form the necessary hemispherical bulb thus gives an unstable arc and unsatisfactory cleaning action. For DC welding thoriated electrodes offer for a stable arc, improved electrode life span, greater current carrying capability along with better arc ignition.

All bout TIG Cold Wire Feeders

A semi-automatic, cold wire-feed machine is a productivity-enhancing tool that's built to improve TIG weld quality and effectiveness, lower costs and permit for quick and consistent filler metal confirmation.

Increase TIG welding productivity by get rid of time-consuming arc stops-and-starts regular with cut-length-rod.

Save 20-40% on filler metal expenses because spooled-wire is less expensive than entity cut-length rod, and the unused rod end fritter away is eliminated!

Condense process variables with continuous spooled-wire which provides quick and consistent filler metal confirmation eliminating the potential weld quality problems associated with unidentified welding alloys.