Connection methods
Cast iron is an alloy of iron with carbon, in which the carbon content is more than 2%.Welding of this material is used in the manufacture of various structures and repair and restoration works. Two cooking methods are used: cold and hot.
Hot welding is a technology in which parts are heated to a temperature of 300-700 degrees Celsius. For this purpose, welding electrodes are used for cast iron or flux-cored wire with the addition of a ceramic rod. Heating is done to ensure that after the work is completed, the structure is evenly cooled and no cracks are formed. Since heating occurs under a high current strength, the cooling process can take 3-5 days.
Note! For hot work, electrodes with a diameter of 8-12 millimeters are used, which consume a current of 600-1000 amperes, respectively.
Cold welding is used more often, because it is more simple. There are several varieties of this process: welding with steel, copper-nickel, nickel and copper-iron electrodes. Before the start of work, the surface to be treated is peeled, milled, drilled in order to obtain a clean surface of the base metal.
Cast iron electrodes and their types
Electrodes for welding of cast iron can be:
- Copper-iron;
- Nickel;
- Steel;
- Ferro-nickel.
- Copper-nickel.
Specialists consider the most high-quality steel, nickel and ferro-nickel electrodes for work.
Steel is an iron-based rod that is used to weld parts from poor-quality, contaminated slag and oil to old cast iron( furnace structures, pumps, heaters, and so on).It is necessary to grind them before processing. It is considered ideal for creating a transitional layer.
Ferro-nickel have a bimetallic core and are used for melting cast iron with lamellar and spherical graphite, ductile cast iron. Also, such rods are used to connect all these materials with steel.
Note! Each type of rod must be used only for its intended purpose, otherwise the connections will be of poor quality.
Features of
rods Working with this material, you must comply with certain conditions, including the correct choice of electrodes. The most popular brands of cast iron electrodes are among domestic manufacturers: ЦЧ-4 , МНЧ-2 , ОЗЧ-4 , 3 and 2. They are used to weld high-density welds and clean surfaces at the end of work. The following rods have the following features:
- Electrodes for cast iron ЦЧ-4 are operated from DC and AC reversed polarity and are used in the cold method of work;
- MHP-2 rods are powered by a reversed polarity DC and are used for vertical and semi-overhead applications.
These rods have a diameter of 3 to 5 millimeters and provide a high quality seam. Domestic electrodes have GOST 9466-75 .The most popular rods of imported production are the brand UTP .Among them there are also universal rods that can be used for various tasks from low-temperature welds to joining cast iron with other metals.
Note! Prices for electrodes depend on the type of application and the country of the manufacturer.