When welding, the temperature shall not be lower than 600 degrees. Covered electrode with large diameter and high current density are selected for slow cooling after welding. Cold welding process: small diameter covered electrode, low current, straight line transportation, each weld length is less than 15MM, and the welding temperature is not hot.
Carbon and silicon are strongly graphitized elements, and the higher the carbon content, the higher the amount of graphite precipitation, while silicon is an element that strongly promotes graphitization and has strong binding force with iron atoms. Carbon exists in the form of graphite, and the adjustment of carbon and silicon content can change the internal metal structure of metal castings. Anode assembly requires moderate strength and hardness of cast ferrophosphorus ring.
Extended data:
In the welding process, the workpiece and solder melt to form a melting zone, and the molten pool cools and solidifies to form a connection between materials. In this process, pressure is usually needed.
In the welding process, if the atmosphere is in direct contact with the high-temperature molten pool, the oxygen in the atmosphere will oxidize metals and various alloy elements. Nitrogen and water vapor in the atmosphere enter the molten pool, and defects such as porosity, slag inclusion and cracks will also be formed in the weld during the subsequent cooling process, which will worsen the quality and performance of the weld.
In order to improve the welding quality, people have developed various protection methods. For example, gas shielded arc welding is to isolate the atmosphere with argon, carbon dioxide and other gases to protect the arc and molten pool rate during welding; For example, when welding steel, adding titanium iron powder with high affinity for oxygen to covered electrode coating for deoxidation can protect beneficial elements manganese and silicon in covered electrode from being oxidized and entering the molten pool, and obtain high-quality weld after cooling.
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