Welding process and Welding essentials of Welding Wire
Welding Wire is used in a variety of fields, and the Welding Wire used in gas Welding is the Wire without the leather. The composition is basically the same as the workpiece, which in principle requires that the weld and the workpiece reach an equal intensity.
When welding alloy steel, cast iron and non-ferrous metal, the melting pool can produce stable oxides of high melting point, such as Cr2O3, SiO2 and Al2O3, etc., to make the weld slag. Therefore, when welding, use the appropriate solder, and can form a low melting slag with this type of oxide, to be able to emerge from the molten pool. Because the metal oxide is more alkaline, the acid flux is generally used, such as borax and boric acid. When casting cast iron, there are often more SiO2, so it is usually used for alkaline flux, such as sodium carbonate and potassium carbonate. When used, it is usually dipped in the end of a Welding Wire.
Welding process of Welding Wire requires extensive study, which is beneficial to the later use.
There are many kinds of Welding Wire. In the related introduction of Welding Wire, we will introduce the Welding preheating of Welding Wire in shandong province.
The low alloy steel structure with higher strength or higher thickness should be preheated before welding. Preheating temperature and the hardenability of steel, plate thickness, limited degree is related to the factors such as hydrogen content, with projects should be combined with the specific circumstances after test to be sure, some recommended preheat temperature can only be used as a reference. When multi-layer welding, the temperature of the interlayer shall not be lower than the preheating temperature, but also avoid the adverse effects caused by excessive temperature of the interlayer, such as the decrease of toughness.
The preheating of the workpiece has important functions such as preventing crack, reducing the cooling speed of the weld and the heat-affected zone, reducing the welding stress. However, preheating worsens labor conditions and complicates the production process. It is necessary to preheat the low alloy steel structure before welding, according to the production practice and welding test results.
In general, preheating should be considered when the carbon equivalent of the parent material is not less than 0.35%. When carbon equivalent is not less than 0.45%, it should be preheated. From the thickness into consideration, the tensile strength of low alloy steel in 500-550 mpa, when thickness more than 25 mm, should consider to be above 100 ℃ preheat before welding. Considering from welds when the environment temperature, plate temperature is lower than 0 ℃, should preheating before welding. The welds can be place around 80 mm within the scope of heated to about 150 ℃.
Oxygen - acetylene flame or other heating method can be used, but the heating mode is not affected. Preheating can be divided into local preheating and integral preheating. When preheating, the heating range should be no less than 80mm on both sides of the weld. Usually in the preheating temperature of 100-200 ℃, when high strength grade steel, the structure rigidity, can be appropriately raise preheating temperature.
Welding Wire Welding process there are many ways is to learn, today Welding Wire manufacturers to introduce the surfacing Welding, Welding Wire Welding is carried out on the edge of the workpiece surface or deposited a layer of abrasion resistant, corrosion resistant, heat resistant performance of metal layer Welding process. The Welding Wire of Welding Wire can improve the service life of the parts, use the materials reasonably, improve the product performance, and reduce the cost and have significant economic benefits. Different workpiece and surfacing welding electrode have different surfacing welding process to obtain satisfactory surfacing welding effect. The most frequently encountered problem in surfacing welding is cracking, and the main method to prevent cracking is to preheat before welding, to control the temperature of the interlayer and to cool after welding. After welding, the stress heat treatment is eliminated. Avoid multi-layer surfacing welding with low hydrogen surfacing welding electrode. When necessary, surfacing layer between the surfacing layer and the parent material.
At present in the field of industrial industry production, the Welding Wire Welding technology and operating workers demands is very high, in practice is not only to avoid cracking, and the Welding Wire Welding workpiece hardness, strength and surface smoothness, and so on to meet the national requirements, which requires the enterprise to have good Welding equipment, so as to maximize after the guarantee Welding quality.