Background  Guidelines for Welding Cast Iron

Cast iron is difficult, but not impossible, to weld. In most cases, welding on cast iron involves repairs to castings, not joining casting to other members. The repairs may be made in the foundry where the castings are produced, or may be made to repair casting defects that are discovered after the part is machined. Mis-machined cast iron parts may require repair welding, such as when holes are drilled in the wrong location. Frequently, broken cast iron parts are repaired by welding. Broken cast iron parts are not unusual, given the brittle nature of most cast iron.

While there are a variety of types of cast iron, the most common is gray cast iron, and these guidelines are directed toward this type of material.

A few facts about cast iron help in understanding the welding challenges. Cast iron typically has a carbon content of 2% - 4%, roughly 10 times as much as most steels. The high carbon content causes the carbon to form flakes of graphite. This graphite gives gray cast iron its characteristic appearance when fractured.

When castings are made, molten iron is poured into a mold and allowed to slowly cool. When this high carbon material is allowed to cool slowly, crack free castings can be made. Remembering this is helpful when welding cast iron: during and after welding, the casting must either be allowed to cool slowly, or should be kept cool enough that the rate of cooling is not important.

A critical temperature in most cast iron is about 1450 degrees F. When at this temperature, conditions that can lead to cracking occur. While the arc will heat the casting to temperatures above this level, it is important that the casting not be held at this temperature for long periods of time.

Electrode selection

If the part is to be machined after welding, a nickel-type electrode will be required. Use Lincoln Softweld® 99Ni stick electrode for single pass, high dilution welds. Softweld 55 Ni is preferred for multiple pass welds. Sometimes, root passes are put in with Softweld 99 Ni, followed by fill passes with Softweld 55 Ni. For welds where machining is not required, and where the weld is expected to rust like the cast iron, Lincoln Ferroweld® stick electrode can be used.

To Heat, or not to Heat

In general, it is preferred to weld cast iron with preheat--and lots of it. But, another way to successfully weld cast iron is to keep it cool--not cold, but cool. Below, both methods will be described. However, once you select a method, stick with it. Keep it hot, or keep it cool, but don't change horses in the middle of the stream!

Welding Techniques with Preheat

Preheating the cast iron part before welding will slow the cooling rate of the weld, and the region surround the weld. It is always preferred to heat the entire casting, if possible. Typical preheat temperatures are 500-1200 degrees F. Don’t heat over 1400 degrees F since that will put the material into the critical temperature range. Preheat the part slowly and uniformly.

Weld using a low current, to minimize admixture, and residual stresses. In some cases, it may be necessary to restrict the welds to small, approximately 1-inch long segments to prevent the build up of residual stresses that can lead to cracking. Peening of weld beads can be helpful in this regard as well.

After welding, allow the part to slowly cool. Wrapping the casting in an insulating blanket, or burying it in dry sand, will help slow cooling rates, and reduce cracking tendencies.

Welding Techniques without Preheat

The size of the casting, or other circumstances, may require that the repair be made without preheat. When this is the case, the part needs to be kept cool, but not cold.

Raising the casting temperature to 100 degrees F is helpful. If the part is on an engine, it may be possible to run it for a few minutes to obtain this temperature. Never heat the casting so hot that you cannot place your bare hand on it.

Make short, approximately 1” long welds. Peening after welding is important with this technique. Allow the weld and the casting to cool. Do not accelerate the rate of cooling with water or compressed air. It may be possible to weld in another area of the casting while the previous weld cools. All craters should be filled. Whenever possible, the beads should be deposited in the same direction, and it is preferred that the ends of parallel beads not line up with each other.

Sealing Cracks

Because of the nature of cast iron, tiny cracks tend to appear next to the weld even when good procedures are followed. If the casting must be water tight, this can be a problem. However, leaking can usually be eliminated with some sort of sealing compound or they may rust shut very soon after being returned to service.

The Studding Method

One method used to repair major breaks in large castings is to drill and tap holes over the surfaces that have been beveled to receive the repair weld metal. Screw steel studs into the threaded holes, leaving 3/16” (5 mm) to ¼” (6 mm)of the stud above the surface. Using the methods discussed above, weld the studs in place and cover the entire surface of the break with weld deposit. Once a good weld deposit is made, the two sides of the crack can be welded together.

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Welding is the most common way of permanently connecting metal parts. In this process, heat is applied to pieces of metal, fusion and fusion into a continuous band. Because of its strength, welding is used in the automotive industry, shipbuilding and repair, aerospace applications, and thousands of other manufacturing activities. Welding is also used to confirm the beams in the construction of buildings, bridges and other structures and all connecting into pipelines, power plants and refineries. 

Welders working in a wide range of industries, production of motor racing. The work in different industries and the equipment used can vary greatly. The most common and easily available welding, arc welding, which uses electrical currents to produce heat and metals are connected, but there are more than 100 different processes can use a soldering iron. The type of solder used is usually determined by the types of metals to be joined and the conditions under which welding is performed. Steel, for example, can be welded more easily than titanium. Some of these processes involve manually with a rod and heat to bond metal, while others are semi-automatic welding with wire feeding machine, binding materials. Automated welding, made entirely by robots, increasingly used in manufacturing. 

As welders, welding and soldering with molten metal to two pieces of metal to connect. However, the metal added during welding and soldering has a lower melting point than the piece, leaving only the molten metal is added, not the piece. Welding uses a melting point below 840 degrees Fahrenheit, welding uses metals with higher melting points. Because soldering and fusing the pieces, these processes tend to distortions and weaknesses of the pieces that can occur when welding to create. Welding is often used for plates and electronic circuits such as computer chips. Welding employees tend to work with small parts that must be clearly posted. Brazing is often used for copper pipes, metal tubes and thinner line than the high temperatures of welding distortion. Soldering can also be used for coatings applied to components to reduce wear and corrosion protection. 

Specialist welding, welding, and workers in general plan to work from drawings, blueprints or specifications and referred to using their knowledge of welding processes and base metals to the best way to help determine the components. The difficulty of the weld is determined by the horizontal, vertical, above or 6G (circular, such as large pipes) and the nature of the metal being melted. Highly skilled welders often are trained to work with a wide variety of materials such as titanium, aluminum or plastic, as well as steel. Welders then select and set up welding equipment, carrying out the planned welds, and welds to be examined to ensure they meet standards or specifications. 

Automated welding is used in a growing number of production processes. In these cases, a machine or robot performs the welding tasks while monitored by a welding machine operator. Issuers of welding, soldering, welding and machine operators and tenders follow specified layouts, work orders, or blueprints. Operators must be properly charged sites and constantly monitor the machine to ensure that it produces the desired link. About 12 percent of all welds, welding, and employees to automated machines. 

The work of the plasma and oxy-gas cutters is closely related to that of welders. But instead of joining metals, cutters use the heat from an electric arc, a stream of ionized gas called plasma, or burning gases to cut and trim metal objects to specific dimensions. Cutters also dismantle large objects like boats, carriages, cars, buildings or airplanes. Some operate and monitor cutting machines similar to those by welding machine operators. 

Work environment. Soldering, welding, and workers are often exposed to a variety of risks, including very hot materials and the intense light created by the arc. Use safety shoes, goggles, masks with goggles and other devices designed to prevent burns and eye damage and protect against falling objects. The Occupational Safety and Health Administration (OSHA) requires that welders working in well ventilated areas safely to the potential for inhalation of gases and particles that can arise from welding to avoid. Because of these risks, welding, soldering and workers suffer more work-related injuries than do workers in most occupations, but injuries can be minimized if safety procedures are followed. Automated welding, soldering and drivers are not exposed to many dangers, and a face shield or goggles usually provide adequate protection for these workers. 

Welders and cutters may work outdoors often in bad weather, or indoors, sometimes in a confined area designed to contain sparks and glare. Outside, you can work on a scaffold or platform high country. They may also be required to lift heavy objects and work in a variety of awkward positions, while bending, stooping, or standing to perform work overhead. 

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Welding can be a very dangerous profession, and it is important for each welder to use all available protective gear. Safety goggles designed to protect your eyes when you're working, they are also recommended for anyone close to your work. Many of the welders are aware of the dangers that can affect vision, but many preferred to ignore the instructions and then welding without protection. 

Welding goggles are designed to keep your eyes safe during welding, can be used instead of the entire plate, and many people want to welders goggles over your helmet, because they are much lighter and cause less strain on your neck muscles. Welding goggles are equipped with lenses that also affect the scratch. Wearing welding goggles to help protect your eyes from harmful UV and infrared radiation, which is produced always read. 

Goggles own data is relatively simple, most of the windows sold today are equipped with a flexible grip easy to adapt. This helps to make the glasses more comfortable and tighter fit that does not allow any harmful rays to enter the holes left ill-fitting spectacles to offer. If you have prescription lenses, welding goggles can be adjusted to fit with prescription lenses. It is also important that the correct lens shade for the type of welding you have to choose. Several different techniques used by different amounts of the electrodes. It is important that the lens tint is the right shade of all kinds of filtering techniques you use. 

Before choosing a seat, you have to confirm that they meet ANSI standards and that the lenses are unbreakable. This ensures a high quality piece of safety equipment purchases. Your glasses should be lightweight, have a tight grip, and are tailored to your facial features and eyes. High quality pair of welding goggles are also well ventilated. High-quality glasses, welder offers more protection than a cheap pair. Protect your eyesight should be a price tag, you should choose the pair that is designed to give you as much protection. 

Welding goggles are a piece of safety equipment any welder should be. They were supposed to be easier to use safety goggles, welder will continue to offer the greatest number of possible security level. 

Welding is a process in which two pieces of metal are joined. This can be done in several ways, including the melting of the metal parts together as filling material, known as "wear parts." Cables are common accessories. Process of welding wire creates smoke, which consists of welded metal parts. These factors, in particular manganese, a common factor in most of the steel and welding materials, such as welding rods, so it is very toxic smoke. 

Armed with years of technical experience in the design, manufacture and commissioning of steel welding electrodes machine. Metals, we have a great team of superior quality and world-caliber professionals. We are a leading manufacturer of welding rods, which supplies all types of welding and cutting equipment. 

We offer our clients a comprehensive range of welding and cutting consumables for quality and cost efficiency by offering both an automated welding and cutting processes. Excellent quality, they have been prepared in accordance with the international design standards and specifications and can be used at most reasonable prices. Different welding and cutting equipment in our store.

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