Rail is mainly composed of manganese and high carbon steel. When covered electrode is welded at low temperature or normal temperature, the arcing temperature rises rapidly to 3250 ~ 4260℃ within one hundredth of a second. The free metal manganese in the flux coating wrapped outside the coated covered electrode rapidly dissociates at the joint surface of the rail at high temperature, resulting in intermittent dissociation, which is often called false welding! Heating the covered electrode of the coating above 120℃ in advance will lead to the formation of manganese, which will be dissociated and well combined in high temperature welding! Neutralize the soft manganese in the rail to form a balance, and strengthen the bonding tension to form high-quality welding! Don't worry, I'm right. This is part of my college thesis. I am a welding major student in Nanjing Institute of Shipbuilding Engineering!