1) A welding rod is a molten electrode coated with a flux coating for electrode arc welding, which is composed of two parts: the flux coating and the welding core. The metal core of the welding rod covered by the flux coating is called the welding core. The core is generally a steel wire with a certain length and diameter.
2) according to the classification of the use of electrodes can be divided into carbon steel electrodes, low-alloy steel electrodes stainless steel electrodes, difficult to weld electrodes, cast iron electrodes, like and nickel alloy electrodes, copper and copper alloy electrodes, aluminum and aluminum alloy electrodes, special purpose electrodes a total of nine.
3) According to the classification of the roasting characteristics of the electrode after the melting of the flux slag can be divided into.
(A) acid welding rod. The composition of the slag is mainly acidic oxide, with strong oxidation, more alloying elements burned, and therefore poor mechanical properties, especially plasticity and impact toughness than alkaline electrodes. At the same time, the acid electrode deoxidation, dephosphorus sulfur ability is low, therefore, the tendency of thermal cracking is also greater. But these welding electrodes welding process is better, the arc length, rust is not sensitive, and good weld formation, good deslagging, widely used in general structures.
(B) alkaline welding rod. The composition of the slag is mainly alkaline oxide and iron alloy. Due to complete deoxidation and easy alloy transition, it can effectively reduce the hydrogen, oxygen and sulfur in the weld. Therefore, the mechanical properties and anti-cracking properties of the weld are better than those of acid welding electrodes. It can be used for welding of alloy steel and important carbon steel. However, the process performance of these welding rods is poor, the arc is difficult to start, the arc stability is poor, the spatter is large, not easy to slag removal, must use short arc welding.