Selection criteria for high frequency welded pipe (ERW) welding consumables
Classification of welding rods:
(1) Classification by slag properties
Welding electrodes can be divided into two categories: acid electrodes and alkaline electrodes. The electrode whose slag is mainly acid oxide is called acid electrode. The electrode whose slag is mainly alkaline oxide and calcium fluoride is called alkaline electrode. Among carbon steel electrodes and low-alloy steel electrodes, low-hydrogen electrodes (including low-hydrogen sodium, low-hydrogen potassium, and iron powder low-hydrogen electrodes) are basic electrodes; electrodes of other coating types are acid electrodes.
(2) Classification by electrode usage
Can be divided into: structural steel electrodes, molybdenum and chromium molybdenum heat-resistant steel electrodes, stainless steel electrodes, surfacing electrodes, low temperature steel electrodes, cast iron electrodes, nickel and nickel alloy electrodes, copper and copper alloy electrodes, aluminum and aluminum alloy electrodes and special 10 categories such as welding rod.
Compared with the acid electrode of the same strength level, the basic electrode has high ductility and toughness of the deposited metal, low diffusible hydrogen content, and strong crack resistance. Therefore, when the product design or welding procedure specification stipulates the use of alkaline electrodes, acid electrodes cannot be used instead. However, the welding process performance of alkaline electrodes (including arc stability, slag removal, spatter, etc.) is poor, and it is highly sensitive to rust, water, and oil stains, and is prone to blow holes.