Control of welding temperatur

Welding temperature control
The melting pool temperature directly affects the welding quality, the melting pool temperature is high, the molten pool is larger, the fluidity of molten iron is good, and the molten iron is easy to melt. However, when it is too high, the molten iron is easy to drip, the back of the single side welding double side forming is easy to burn and wear, forming the welding, forming also difficult to control, and the plastic property of the joint is reduced and the bending is easy to crack. When the bath temperature is low, the weld pool is small, the molten iron is dark, and the fluidity is poor.
The melting pool temperature is closely related to the welding current, electrode diameter, electrode angle and arc burning time. The following measures are taken to control the temperature of the molten pool.
diameter
1. Welding current and electrode diameter: welding current and electrode diameter are selected according to the space position of welding seam and welding level. The welding current and electrode diameter are larger and the vertical and pitching positions are smaller when the welding is open. For example, the welding electrode of 12mm flat butt butt welding is selected with the welding rod of 3.2mm, the welding current: 80-85A, filling, the welding current of phi 4.0mm, the welding current: 165-175A, the reasonable selection of welding current and electrode diameter, easy to control the weld pool temperature, is the foundation of the weld forming.
Method
2. The temperature of the circle shaped strip weld pool is higher than that of the crescent shaped strip. The temperature of the crescent shaped strip is higher than the molten pool temperature of the sawtooth strip. The sawtooth strip is used in the 12mm flat welding bottom layer, and the temperature of the molten pool is controlled effectively by the amplitude of swinging and the pause on both sides of the slope, so that the size of the molten pool is basically the same. As a result, the probability of not forming the welding and burning on the root of the bevel has been reduced, and the non penetration is improved. It is no longer the difficulty for the single side welding of the butt butt welding.
angle
3, the angle of welding rod, the angle of welding rod and welding direction is 90 degrees, the arc is concentrated, the temperature of the molten pool is high, the angle of the weld is small, the arc is scattered, the melting pool temperature is low, such as the 12mm flat welding bottom layer, the welding rod angle: 50-70 degrees, the melting pool temperature has fallen to some extent, avoiding the back generation welding or the height. For example, after replacing the welding rod with the bottom layer of the 12mm plate, the joint uses 90-95 degrees of welding electrode angle to improve the temperature of the molten pool, the melt hole can be opened smoothly, the back forming is more flat, and the inner concave phenomenon of the joint is effectively controlled.
time
4. In the practice teaching of the arc burning time, the horizontal fixing and the vertical fixed welding of the 57 x 3.5 tubes, the arc breaking method is used for welding. The frequency of arc breaking and the burning time of the arc directly affect the temperature of the molten pool. Because the tube wall is thinner, the capacity of the arc heat is limited, and if the arc frequency is slowed down to reduce the melting rate The pool temperature is easy to produce shrinkage hole, so it can only use arc combustion time to control the melting pool temperature. If the molten pool temperature is too high, the arc combustion time can be reduced and the temperature of the molten pool is reduced. At this time, the melting hole becomes small and the inner forming height of the tube is moderate, and the weld seam is too high or the weld is produced.
The control device mainly provides the signal control resistance welding machine to turn on and cut off the welding current, control the welding current value, and carry out the fault monitoring and processing.