noun
welding flux
Technical term for a material used in welding to prevent oxidation and improve the quality of the weld.
溶接剤は、溶接部の酸化を防ぐために使われる。
Welding flux is used to prevent oxidation of the weld area.
Compound of 溶接 (yōsetsu, 'welding') + 剤 (zai, 'agent, material').