Oxy-Fuel Welding (OFW)

Oxy Fuel Welding (OFW) is a metal joining process, used to join metal end pieces by heating. This process is commonly used to join mild steel. Oxy-Fuel welding is also called oxyacetylene welding because in this process mixture of acetylene and oxygen burns at intense flame of 3500^oC. Oxyacetylene gas welding consists of a group of welding processes, which joins different type of metals by heating them whether it is used with gas flame or without filler metal. When the gas flame combined with metal, it melts the surface to molten form, by allowing the welding process to take place. Oxy-Fuel welding can be used for shaping metal, cutting and brazing of metals. Oxy-fuel welding is mostly used for prefabrication of tubes, steel sheets and plates.

Oxy-FuelWelding process includes welding operations that make use of oxygen, which can also be combined with fuel gas as a heating medium. In this process, gas, fuel and oxygen are mixed in a mixing chamber with proper proportion that also a part of the welding assembly. This welding process involves a filler metal and the melting of the base metal, which can be used by means of the flame produced at the tip of welding torch.

Oxy-Fuel Welding Processes

There are following three processes that involves in Oxy-Fuel Welding.

• Oxy-acetylene welding
• Oxy-hydrogen welding,
• Pressure gas welding.

Oxy Fuel welding also known as air acetylene welding because of its industrial significance, in which combustion of air and acetylene heat is obtained. Welding with Methyl acetone- propadiene gas (MAPP gas) also uses same procedure like Oxy-fuel welding.

Advantages of OFW

There are following given advantages of oxy Fuel welding:

• A welder can control temperature of weld zone, heat input and the oxidizing or reducing potential of the welding environment that controls the welding process.
• Welding process also controls the shape, weld bead size and weld puddle viscosity as it independently adds a filler metal of the welding heat source.
• Oxy Fuel Welding is used for welding of tubes, thin sheets and small diameter of pipe.
• OFW is also used to repair welding joints, welds of thick sections. However, its repair work is not very economical, so its use is not feasible at commercial level.

Oxy fuel welding process is used in welding shops, it is mostly used for torch brazing, soldering, and many other types of operations, where its heat transfer rates and flame characteristics are not the same like that of welding.

Shielded Metal Arc Welding (SMAW)

SMAW is a process of welding that uses a fragile electrode coated in flux. SMAW have many names this process is also known as stick welding, Manual Arc Welding or flux shielded arc welding. In SMAW process as the weld is laid, the external coating of flux on electrode disintegrates, providing a layer of slag and a shielding gas. These elements protect the weld area from infectivity until the area cools. The external flux coating also performs more functions such as it provides control bead shape or arc stability.

Equipment & Operation for SMAW

The following equipment and operations are necessary for SMAW process.

• Welding power source
•  Electrode holder
• Ground clamp
• Welding cables and connectors
• Accessory equipment (It includes wire brush, chipping hammer)
• Protective equipment (It includes gloves, helmet etc.)

Welding Power Sources

Shielded Metal Arc Welding circuit we can use either Direct Current (DC) or either Alternating Current. In some specific cases, the power source must use constant current type. In this type, power source will deliver relative welding current or constant amperage. As it will remains constant so the weld beads which are produced will be uniform in shape and size.

Electrode Holder

The use of electrode holder is to connect different welding cables and ducts to the electrode. Electrode holder is available in different sizes and capacities. The purpose of insulated handle is to guide electrode over the weld joints.

Ground Clamp

The purpose of the ground clamp is to connect the ground cable to the work piece. A good ground clamp having the characteristics of carrying more electric current without overheating.

Welding cables and connectors

Electrode cable and ground cable plays an important role in the SMAW circuit. So different welding cables and connectors are also necessary components for the SMAW circuit.

Coated Electrodes

In Shielded Metal Arc Welding various types of coated electrodes are used. For different types of welding specific electrodes are used according to their types. For example, electrodes used for low allows and stainless steels will quite different from the coated electrodes which are used for mild or carbon steel.

For information about the Fabrication or welding you can also visit http://millenniumind.com/

Welding Repair

Weld repair is a process in which remove the damages of a metal. Metal damages removes from the use of Oxy fuel welding and by using carbon arc gouging or plasma cutting. For a good metal weld repair we must follow the steps which are involves in weld repair process.

Welding Procedure

For the use of welders a logical procedure of welding is to be applicable. In this procedure use special metal fillers and preheat the metal. In most of the construction companies, we can successfully weld a steel metal by using the following three steps which are:

•  In first step, Cutting the metal into the parts and removed the defected Components.
• In second step, prepare the new metal weld joints
• In third step, welding and cleaning the metal.

Step 1: Cutting metal into the parts and removed the defected components.

In the first step of welding repair removes the damages of a metal. This step can complete with the use of different welding techniques. Plasma and oxy-fuel are used for cutting a metal. We can also use carbon arc gouging which is well suited for removes the cracks from metal without harming the other parts of a metal.

With the help of different tools we can repair a metal. One of the most commonly used for cutting a metal is Oxy-fuel torch. Another tool which is used for cutting a metal is plasma cutters. By using plasma cutters welders can cut small parts width of metals. Plasma cutters are faster than the Oxy-fuel torches because by using plasma cutter welders can also cut electrical conductive metals but with the use of oxy-fuel torch welders can’t cut the stainless steel or aluminum metals. One of the most other common tools is carbon arc gouging which is used for welding generators. In using a carbon arc gouging uses an electrode which is made up of a carbon. By using this electrode welder can remove the defected parts. In result high pressure stream of air will released.

Step 2: prepare the new metal weld joints.

In the second step, welder will choose the filler material and replace all the parts with selected material which is better and have more power strength of the previous original material. According to their different mechanical properties such as tensile strength, wear resistance and ductility etc they have different applications. For avoiding long term failure of welding must ensure the quality and remove the unwanted downtime defects. When you will choose the right alloy then cut the steel and bevel the edges. After this preheating is required this is to be done by the use of oxy fuel torch.

Step 3: Welding and cleaning the metal.

In the third and last process, welders choose the welding process which they will follow to weld a metal. There are two most commonly used processes are:

•            Shielded Metal Arc Welding (SMAW)
•            Flux Cored Arc Welding (FCAW).

This article is all about the welding repair process. Millenniumind industry will offer the all these services.

For more details you can also visit at http://millenniumind.com

Safety Practices For Fabrication Shop Work

Fires blown up due to welding are avoidable, if workers follow those safeguards & practices prescribed by workshop administration before stepping into it, then precious lives could be saved from loss. 1.4% residential fires & 10% commercial fires reported in Irving – Texas due to welding accidents in 2002. Negligence in preventive measures give rise to such incidents, workers could overcome them by adopting prescribed standards of protection.

It is necessary for welders whether they are professional or unprofessional to know about potential threat of catching fire on fabrication shop, as work at high currents during make and break of connections.

Must do Checkups:
First thing first, before getting into work you should examine:

• Equipment’s health, 
• Working & surrounding area, 
• Available items to minimize hazards and 
• Measures that can ensure safety.

Checking of Equipment:
In order to avoid any accidents, the installation of the welding equipment should be done by qualified technicians, which can ensure about the connectivity as well as operation of apparatus according to manufacturer’s instructions. However, installed equipment correct operation i.e. cable, electrode holder and coupling devices is verified at welder’s end, he should be competent enough to identify, recover or report about the defects. The welder should make sure each time he uses the equipment, the external connections are clean & tight, clamp of wire has firm grip to grab the workpiece and appropriate distance between welding point & workpiece.

Reduction of Electric Shock Risk:
In arc welding, the major hazard that you might come across is the arc radiation and electric shock, it may occur due to appearance with live parts i.e. electrodes and workpiece of welding circuit. Certified welding shops use proper safety & protection system, as voltage seepage during rainy season increases as compared to normal.

More than One Welding Operations at One Workpiece:
There is a huge risk of electric shock when more than one workpieces have physical or electrical connection. Complete isolation of workpieces should be observed, else it will increase the probability of electrocuted in case of simultaneous connection.

Outdoor Working:
While working outdoor welding repair the possibility of moisture increases, it also increases voltage leakage. In such case, system requires sufficient level of waterproofing, for enclosures the ingress protection (IP) codes should be:

• IP 23 protection against water spray <60 degrees from vertical
• IP 24 protection against water spray from any direction

In case of rainfall, welder, equipment & workpiece should have complete protection from moisture.

Some Safety Practices to Avoid Tragic Situations:
The safety practices are as follows:

• The welders should takeoff ornaments like rings and metallic straps before getting started with work.
• The clothing like gloves, boots & overalls should be used to protect from electric shock.
• The external connection of the welding apparatus should be checked on daily basis, whether connections clean and fixed or not.
• The electrode of manual metal arc welding (MMAW) should have insulation for protection, to change the electrode.
• High frequency (HF) can make welder feel electric shock, HF could affect even through small hole in glove.

Fabrication classes

Fabrication classes

Metal fabrication shops includes many processes of producing metal elements by ever-changing the raw metal material exploitation varied tools. The processes are classified as cold, heat and hot operating betting on the temperature at that the fabric is processed. Most of the objects around USA like paper clips, computers, bolts, nails, automobile components, components used for instruments and machinery and myriad alternative merchandise are remodeled by metal fabrication processes like bending, punching, drilling, turning, grinding, threading etc. The factors influencing the method enclosed the kind of fabric being machined, the speed of production, the specified pure mathematics, and alternative physical needs of the half.

Fabrication is divided into the subsequent classes. 

Metal Forming:

• Bending: All through bending, the work piece is bent to make flanges, contours, curls, seams, corrugations and alternative geometries by means that of applying force through hydraulic, gas and electrical machines. 

Shearing
• Conventional shearing: cutting off could be a metal cutting method through that flat surfaces cut employing a scissors-like action, typically in straight lines.

• Turret Punching: Turret Punching creates shapes in sheet material by in turn punching a series of basic shapes. Edges are cut by the cutting off action of a punch and die.

Material Removal

• Sawing: Sawing could be a variety of cutting within which the cutting implement could be a blade that incorporates a series of teeth, with every tooth removing a tiny low quantity of fabric. Sawing is usually wont to form stuff to the approximate size of the half, before further processes. 

• Sound: Tapping produces internal threads within the work. This involves use of a tool with multiple cutting teeth.

• Boring: Boring produces circular internal profiles in hollow work or on a hole created by drilling or another method.

• Turning: Turning rotates the work concerning its axis whereas applying cutting tools to form a desired form.

• Drilling: Drilling produces holes in an exceedingly work employing a fluted cutting implement.

• Edge: Milling removes little chips employing a rotating cutter that moves in 3 axes. 

• Grinding: Grinding could be a chip removal method within which the cutting implement is associate abrasive grain wheel. Differing kinds of grinding embrace Surface grinding, Cylindrical grinding, Internal grinding and Center less grinding.

Advanced strategies

• Optical device cutting: Laser cutting involves focusing a beam of high density energy on the surface of the work. The beam evaporates parts of the work in an exceedingly controlled manner.

• Electro Discharge Machining: Electro discharge machining is predicated on erosion of metal by spark discharges. This method is used for machining associate material that is an electrical conductor. 

• Wire EDM: The wire EDM or Electro Discharge Machining produces half shapes by cutting a metal work piece with a endlessly moving wire by means that of fast, repetitive spark discharges.

This method is employed to chop skinny and thick metal and is commonly wont to create punches, tools and dies from laborious metals. 

• Water jet Cutting: during this method, the force of a water jet is employed to chop material. The water jet acts sort of a saw and cuts slim kerfs within the work. Most of metals, plastics, fabrics, wood merchandise, and rubber, building material, leather, brick and composite materials are cut exploitation the water jet method.