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Master the correct method of welding, you are not far away from the welding master

Edit£º   Browse£º654  Date£º2021-07-20
In the welding process, the movement of welding rod relative to the weld is called moving rod. The movement of welding rod includes three actions: feeding along the axis of welding rod, longitudinal movement and transverse swing in the direction of no welding seam axis.
1) The basic movement of the strip
The electrode is fed along the axis to the molten pool, so that the length of the arc can be kept unchanged after the electrode is melted. Therefore, the speed of the electrode feeding to the molten pool is required to be equal to the speed of the electrode melting.
If the speed of electrode feeding is less than the speed of electrode melting, the length of arc will increase gradually, resulting in arc breaking; If the speed of electrode feeding is too fast, the length of arc will be shortened rapidly, and the short circuit between the end of electrode and the weldment will also make the arc extinguish.
The welding rod does not move longitudinally in the welding direction, which makes the deposited metal of the welding rod form a weld with the melted base metal.
The lateral swing of the electrode. The function of electrode lateral swing is to obtain a certain width of weld and ensure good fusion on both sides of the weld. The swing range should be determined according to the width of the weld and the diameter of the welding rod. The required weld width and speed can be obtained only when the lateral swing force is uniform. The normal weld width is generally not more than 2-5 times of the electrode diameter.
2) Transportation method:
There are many ways to transport the welding rod. The selection should be based on the form of welding joint, assembly clearance, space position of welding seam, diameter and performance of welding rod, welding current and welder's technical level.
The welding rod should swing laterally when it is running. The purpose is to obtain uniform weld formation, and also to control the temperature of the molten pool and prevent the weld from burning through due to the high temperature of the molten pool.
According to the different methods of welding rod lateral swing, the commonly used methods in the welding process are: straight-line method, straight-line reciprocating method, crescent method, oblique circle method, triangle method and sawtooth method.
The straight-line strip transportation method is as follows
In this welding method, the welding rod does not swing laterally, but moves linearly along the welding direction. It is commonly used in butt welding without groove, multi-layer and multi pass welding
Method of linear reciprocating strip transportation:
The end of the welding rod swings along the longitudinal direction of the weld. This method has the advantages of fast welding speed and narrow weld formation. It is suitable for single side welding and double side forming in flat welding position with narrow gap. It is especially suitable for stainless steel welding. It is conducive to controlling the temperature of the molten pool in the welding process and ensuring the weld formation.
Methods of crescent shaped sliver transportation:
The end of the welding rod should swing left and right in crescent shape along the welding direction, the middle action should be fast, and the two sides should stay a little. This method can effectively control the temperature of the molten pool. The molten pool is shallow and the undercut on both sides should be prevented. Crescent shaped strip welding is one of the main methods of single side welding and double side forming continuous arc welding.
Zigzag strip transportation method:
The sawtooth at the end of the welding rod swings forward and stops on both sides to prevent undercut. This method is easy to operate and widely used. It is suitable for the welding of butt welds in horizontal, vertical and overhead positions.
The method of regular triangle strip transportation is as follows
Regular triangle strip moving method
The end of the welding rod is transported forward in a continuous and uniform triangle. This method is suitable for thick plate welding, and it is good for melting metal when welding root. The joint of weld is a difficult link to master in single side welding and double side forming backing welding.
If the joint method is proper, the front and back sides of the weld are even and smooth, and there are no internal defects; If the method is not proper, it is easy to produce defects such as weld bead, high residual height, depression and disconnection. The quality of joint is related to the quality of arc striking and weld ending.
Generally speaking, if the arc striking is quick and proper, and the temperature at the end of preheating or front welding is kept high, the weld joint is easy and the joint quality is good. If the electrode is replaced slowly or the arc is unstable during arc striking, a good weld joint cannot be obtained.
The method of moving strip by oblique triangle is as follows
When welding with this method, the action is the same as that of regular triangle. It is suitable for welding fillet weld in horizontal and upward position and transverse weld with groove.
The positive circle method was used
When welding with this method, the electrode moves forward continuously in a positive circle (Fig. It is suitable for flat weld of thick weldment.
Method of slant circle strip transportation:
The end of the welding rod moves forward in an oblique circle. This method is suitable for overhead welding of riding type tube sheet, single side welding and double side forming backing welding of plate and tube 45 degree oblique position or transverse position of thick plate.
When welding with this method, the action of electrode is the same as that of positive circle. It is suitable for flat and inverted T-joint welds and butt transverse welds.
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