Typical applications include the back-gouging of weld seams to reach the deposited weld metal from the other side of the workpiece, the removal of gates and risers from castings, the removal of old or excess weld metal so that equipment can be repaired and the reshaping of torn metal prior to welding repair, notably on …

What is the purpose of gouging out a weld?

The main goal of air arc gouging is to remove defective or old welds to repair or dismantle equipment. Unlike oxy-fuel cutting, air arc gouging avoids the need for oxidation of the metal to cut. The rate of metal removal depends on the efficiency of air jet in removing molten metal and the melting rate.

What is gouging?

What Does Gouging Mean? Gouging is a type of corrosion that occurs on a metallic surface in which a hole, groove or indentation is created. Gouging happens in boiler tubes because of caustic corrosion that occurs as a result of excessive use of alkalines such as sodium hydroxide (NaOH).

What is a gouging rod used for?

Gouging electrodes are made of carbon and have a copper coating. Gouging carbon rods are used for metal removal at fast rates with low power consumption. It is generally used to remove welding defects, excess welds and foundry risers from cast products.

Why is back gouging needed?

Back gouging is a process of cutting a groove in the back side of a joint that has been welded. Back gouging can ensure 100% joint fusion at the root and remove discontinuities of the root pass. This process can also remove the root pass metal if the properties of the metal are not desirable to the finished weld.

What are gouging rods made of?

It employs a consumable carbon or graphite electrode to melt the material, which is then blown away by an air jet. This process is useful for cutting a variety of materials, but it is most often used for cutting and gouging aluminum, copper, iron, magnesium, and carbon and stainless steel.

Why is plasma arc gouging used?

The plasma gouging arc is less constricted than the cutting arc. The goal of plasma arc gouging is to maximize the volume of metal removal. For this reason the torch parts used in gouging are designed to produce a wider and softer arc.

What is gouging torch?

Gouging is carried out using a torch through which oxygen and a fuel gas (acetylene, propane or mains gas) are passed. … Rapid oxidation of the steel takes place and material is removed by the pressure of the gases.

What is gouging in pipe?

A gouge is created when metal is removed from the pipe wall through mechanical means. … The sharp edges of the gouge act as stress concentrators and pose a threat to the integrity of the pipe. When mechanical damage to the pipe occurs, the pipe coating is usually damaged as a result.

What is backing in welding?

Backing is defined as material placed at the root of a weld joint for the purpose of supporting molten weld metal. … Welding the second side of a double-sided butt joint is regarded as welding a joint with backing because the first weld run put in from the second side is supported by weld metal from the first side.

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What is peening in welding?

Peening is a welding process that helps the weld joints to reduce stress concentration. By peening, the weld joint stretches as it undergoes cooling, relieving it of its internal stress. Peening is applied to fillet welds or weld joints with shallow cracks on the surface as it increases the fatigue resistance.

Can all plasma cutters gouge?

Most modern plasma cutting machines have the ability to gouge as well as cut. If you’ve already got a plasma cutting machine, there’s absolutely no reason you shouldn’t start plasma gouging.

What are the types of carbon arc gouging electrodes?

There are three types of carbon electrodes: AC coated electrodes (for use with AC power sources), DC plain electrodes and DC copper-coated electrodes. The latter is most widely used because of their comparatively long electrode life, stable arc characteristics and groove uniformity.

What causes arc strikes?

Arc strike This is a defect caused by instantaneously striking an arc on the base material. In other words, an arc strike is a spot of failed arc ignition which was not fused by subsequent welding and remained on the base material. Arc strike may be the cause of cracking in the base material.

What is a injurious dent?

(d) Plain dents are defined injurious if they exceed a depth of 6% of the nominal pipe diameter. Plain dents of any depth are acceptable provided strain levels associated with the deformation do not exceed 6% strain.

What is a gouging machine?

The Reeds ‘n Stuff gouging machine is the ultimate machine for gouging your cane. Its newly designed cylindrical blade provides the most accurate cuts and a perfectly smooth surface. And an ingenious thickness adjustment keeps the blade centred at any settings.

What is progressive gouging?

Progressive gouging Gouging is conducted in either a continuous or progressive manner. Applications include removal of an unfused root area on the reverse side of a welded joint, part-shaping a steel forging, complete removal of a weld deposit and preparing plate edges for welding.

What is back gouging?

marine. The removal of weld metal and base metal from the weld root side of a welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side. See also Gouging.

Why electrode is coated with flux?

The electrode is coated in a metal mixture called flux, which gives off gases as it decomposes to prevent weld contamination, introduces deoxidizers to purify the weld, causes weld-protecting slag to form, improves the arc stability, and provides alloying elements to improve the weld quality.

What is difference between back and backing welds?

A back weld is when a weld is created on the back side of the joint after the groove weld is performed. A backing weld is applied to the root of a groove before welding the groove. … Therefore, a note in the tail of the welding symbol may specify which type of weld is required or it may be specified in the legend.

What is weld speed?

The weld speed that the commercial welder has to choose is the speed of travel of the torch ad it is dependent on the flow rate of the material that has to be welded and also on the thickness of the material that needs to be welded.

What is the function of flux in submerged arc welding?

What is the function of flux in submerged arc welding? Explanation: Flux is used to completely cover the welded zone. It prevents oxidation of weld joint and spattering of molten metal.

Which increases the porosity on the weld?

As little as 1% air entrainment in the shielding gas will cause distributed porosity and greater than 1.5% results in gross surface breaking pores. Leaks in the gas line, too high a gas flow rate, draughts and excessive turbulence in the weld pool are frequent causes of porosity.

What is gouging steel?

Gouging is the term to define a type of corrosion which occurs on a metallic surface in which a hole, groove or indentation is created. … Particularly in maintenance and repair, the ability to gouge or groove metal is critical and deserves full consideration.

Can a plasma cutter Weld?

With the right torch design, a nitrogen-water injection, less expensive than other gases, can work well when plasma cutting aluminum and stainless material for subsequent welding. The process involves an electrode surrounded by nitrogen, which is heated by an electric arc to form the plasma.

Can you cut bolts with a plasma cutter?

They also can be used to cut nearly anything that is metal, including steel, stainless steel, and aluminum. You can even use them to cut rusty nuts and bolts just like you would use a gas torch, only much faster and with cleaner results. … Treat plasma cutting like welding and gas torch cutting, and you will be OK.