Lanthanated tungsten electrode is European countries introduced in the eighty s hope replace thorium tungsten products improved varieties, once launched, with its excellent welding performance attention and is very popular in international welding area, especially the European welding academic, for this reason, the lanthanum tungsten volume after the thorium-tungsten electrode, but awareness is not high in the domestic market. Its characteristic is that the conductivity is closest to 2% thorium tungsten electrode, the durable current is high and the burn rate is low.
The most common lanthanum tungsten electrode contains 1% lanthanum oxide (La203), known as lanthanum oxide. In Europe and Japan, lanthanum tungsten electrodes have been the most commonly used alternative to thorium tungsten electrodes in most applications. There are 3 kinds of lanthanum oxide, lanthanum oxide 1.5% and lanthanum oxide 1%. Lanthanum trioxide has the lowest electron emission, the easiest arc initiation and the lowest tip temperature, which helps prevent grain growth and improve service life. Tests on 2 percent lanthanum tungsten electrodes have shown that if there is no overload current, the life span is longer than thorium tungsten, and arc initiation is easier in most applications.
Especially good at (a) preventing thermal shock, (b) good welding and (c) avoiding pollution in the case of repeated ignition during short cycle welding. The welder was particularly pleased with the lanthanum tungsten electrode when welding the pipe. Long service life reduces downtime. Moreover, in general, the lanthanum tungsten electrode of lanthanum oxide is also required, which is easy to arc under low current flow and can stabilize the arc under low current. Lanthanum in tungsten electrodes is a rare earth and is not radioactive. This kind of lanthanum tungsten electrode is mainly used for dc welding, which also has good effect in ac welding. Lanthanum - tungsten electrodes containing 1.0% lanthanum oxide are on the market together with cerium - tungsten electrodes.
Lanthanated tungsten electrode manufacturing method, involves a is mainly used for TIG (tungsten inert gas) welding and PLASMA (PLASMA) technology, metal welding, cutting, spraying, smelting methods of making a kind of tungsten electrodes.
(1) prepare lanthanum tungsten-coated powder by mixing lanthanum acetate with solid materials including APT, WO3 and W powder and adding water evenly;
(2) lanthanum tungsten coated powder in the decomposition process of lanthanum salt is in hydrogen atmosphere with a simultaneous reduction process, a reduction in 600 ~ 700 ℃, the temperature control for 2 ~ 3 hours, secondary reduction temperature control in 800-970 ℃, in the process of hydrogen flow rate is 0.5 2.0 m3 / h.
