Submerged arc welding is a process where welding occurs beneath a bed of granular flux with an automatically fed consumable wire electrode. The flux covers the welding area and shields it from atmospheric contamination. It is advantageous for thick sections, high welding speeds, and outdoor applications but requires more equipment. Electro slag welding uses an electrically heated slag pool rather than an arc and is useful for vertical-up welding of thick sections with deep penetration and fewer defects.