Gas welding and gas cutting

Gas welding uses heat to melt and weld metals together. The material itself has not changed. It's a physical change. The purpose of gas cutting is to make molten metal pass through, then make excessive oxygen pass through, make molten iron react with oxygen to form metal oxide, and then metal and newly formed metal are oxidized. The properties of materials are separated and separated, so the purpose of cutting can be achieved, so gas cutting is a chemical change.


There are two directions for gas welding operation:
(1) left hand welding: the welding wire and torch move from the right end of the weld to the left end. The welding wire is in front of the welding torch, and the flame points to the weldment of the part to be welded. The utility model is characterized by simple and convenient operation and is suitable for welding thin and low melting point workpieces.


(2) right hand welding: the welding wire and torch move from the left end of the weld to the right end, the welding wire is behind the welding torch, and the flame points to the welding part of the weldment. It is characterized by that the flame always covers the welding metal during the welding process, which makes the molten pool cool slowly, which is conducive to improving the structure of the welding metal, concentrating heat, deep melting and suitable for welding thick workpieces. But the operation is hard to master.


The gas cutting process is divided into three stages:
(1) preheating: at the beginning of gas cutting, use gas flame (oxyacetylene flame or oxypropane flame) to preheat the workpiece to be cut to the combustion temperature ignition point of metal materials (about 1100-1150 ° C). Carbon steel).


(2) combustion: jet high-speed cutting oxygen flow to make the metal reaching the ignition point burn strongly in the oxygen flow and form oxide.


(3) slag blowing: the oxide formed by metal combustion is blown by oxygen flow to form a slit, which separates the metal and completes the cutting process.