Hydrogen may be the smallest atom, but in welding it creates serious problems. During welding, hydrogen enters molten metal from moisture, flux, or electrodes. As the weld cools, hydrogen becomes trapped inside the crystal structure and builds internal pressure. This makes the metal brittle and leads to delayed cracking, especially in the heat affected zone. This failure is known as hydrogen induced cracking or hydrogen embrittlement. Using low hydrogen electrodes, proper preheating, and dry ele