Welding Flux  is generally classified as acid flux and alkaline flux are two kinds of low-carbon steel is the most commonly used and most economical acid flux, such as the HJ431 with the H08A or H08MNA, welding of the more important low alloy high strength steel can be used alkaline flux SJ101 SJ301, to to tie H08MNA wire to use, can significantly improve the mechanical properties and toughness of the weld.