Argon arc welding these key steps can not be ignored!

1. The arc Argon arc welding has three kinds of arc initiation: scratch arc initiation, lift arc initiation and high frequency arc initiation. Scratch strike arc is the tungsten pole and the workpiece scratch, at the same time, the short circuit current will be heated tungsten pole, lift the welding gun can arc ignition. This arc starting mode is simple to control and easy to operate. To lift the arc, the tungsten pole and the workpiece will be short-circuited at first, and the short-circuit current will be very small. When the tungsten pole is heated and the tungsten pole is lifted away from the workpiece, the current will be switched to the arc striking current in a very short time to ignite the arc. Its advantage is to avoid high frequency interference and reduce the tungsten pollution of the workpiece. High frequency arc starting: high voltage generator is used to break through the air discharge and ignite the arc. The most common way of arc starting is breakdown type, that is, holding the torch perpendicular to the workpiece, making the tungsten electrode and the workpiece maintain a distance of 3-5min, connect the power supply, under the action of high voltage high frequency or high voltage pulse, the breakdown gap discharge, make the protection gas ionize to form ion current and ignite the arc. This method is widely used because of its good condition, low burning loss and good arc starting quality. 2. Weld pool control Control the shape and size of molten pool at the end of the day is to control the welding temperature, the influence of temperature on the welding quality is very big, produce all kinds of welding defects was caused by improper temperature, hot crack, crack, bite edge, arc pit sag, elements, burning, convex tumor because of excessive temperature, cold crack, air hole, slag inclusion, incomplete fusion, incomplete fusion, etc. Are the result of the soldering temperature is not enough. 3. The arc Arc has certain requirements and law: welding torch axis and has been referred to as the welding torch inclination Angle welding surface, it directly affect the effect of heat input, protection and operation view, general welding torch Angle is 70 ° to 85 °, welding torch Angle 90 ° protective effect is best, but from the protection of the welding torch of airflow increased with the increase of welding torch movement speed backwards deviation, may make molten pool can not get adequate protection, so the welding speed not too fast. GTAW generally adopts the left – hand welding method. 4. Holding torch Hold the torch handle with your right thumb and index finger, and touch the workpiece with the other three fingers for guidance. Rocker: press the welding nozzle slightly hard on the welding seam, and shake the arm greatly to weld. Advantages: because the welding nozzle is pressed on the welding seam, the welding handle is very stable in the operation process, so the welding seam is well protected, of good quality, the appearance is very beautiful, and the qualified rate of the product is high. Especially welding is very convenient, welding stainless steel can get a very beautiful appearance of the color. Disadvantages: difficult to learn, because of the arm swing range, so can not be in the obstacle welding. Mop: welding nozzle gently rely on or do not rely on the weld, the right little finger or ring finger is relying on or do not rely on the workpiece, arm swing small, dragging the welding handle for welding. Advantages: easy to learn, adaptable. Disadvantages: forming and quality is not good, especially without the handle for easy welding, welding stainless steel is difficult to get the ideal color and forming. 5. Wire grip method The middle finger of the left hand is on the top and the fourth finger is on the bottom to hold the welding wire, the thumb and index finger hold the welding wire forward to move into the molten pool, and then the thumb and index finger loosen and then hold the welding wire forward, so that the whole welding wire can not stop the transmission finished. Wire feeding Angle, feeding mode and proficiency related, it directly affects the geometry of the weld. The wire should be sent in at a low Angle, usually 10°-15°, usually no more than 20°. This helps to cover the melting end with protective gas and to avoid colliding with the tungsten electrode, shortening the distance between the wire and the pool in a droplet form. Wire feeding action to light, do not stir the gas protective layer, so as to avoid air invasion. When the welding wire enters the welding pool, it is necessary to avoid short circuit with tungsten electrode, so as to avoid tungsten electrode burning loss falling into the welding pool and causing tungsten clamp in the welding seam. The end of the welding wire should not extend into the arc column, that is, between the welding pool and the tungsten pole; otherwise, under the action of the high temperature of the arc column, the welding wire will melt violently and drip into the welding pool, causing a flying splash and a banging sound, thus destroying the steady arc combustion of the arc, which will result in the internal pollution of the welding pool, and also make the welding seam look bad and not bright. Wire melting into the molten pool can be roughly divided into five steps: A. The welding torch is perpendicular to the workpiece, igniting an arc to form a molten pool. When the pool is heated by an arc to appear white and will flow, it is ready to send the welding wire into the pool. B. Move torch slightly backward and tilt 10°-15° C. Send the welding wire end to the inside edge of the strong discharge to 1/3 of the welding pool, and melt the welding wire by the heat of the welding pool. Do not stir the welding pool like gas welding (BC simultaneous). D. Draw back the welding wire but its end does not leave the protection zone, and remains as separate from the front edge of the weld pool ready to add the welding wire again. The torch moves forward to the front of the pool to form a new pool. (repeat CDE action until the end of welding) 6. Wire Wire feeding can be divided into three types: outer filling wire, inner filling wire and ethereal method. Outer wire filling: it can be used for backing and filling with large current. The welding wire head is on the front of the groove, and the left hand pinch the welding wire and continuously send it into the weld pool for welding. The groove clearance is small or no. Advantages: high production efficiency and easy operation skills due to large current and small gap. Disadvantages: used for the bottom, because the operator can not see the blunt edge melting and negative residual height, so easy to produce no fusion and can not get the ideal negative forming. Inner wire filling: it can only be used for bottom welding. Use left thumb, index finger or middle finger to cooperate with wire feeding action. The welding wire is close to the blunt edge on the inside of the groove, and melts together with the blunt edge for welding. The groove gap is required to be larger than the diameter of the welding wire. If it is a plate, the welding wire can be bent into an arc. Advantage: because the welding wire is on the opposite side of the groove, it can clearly see the fusion of the blunt edge and the welding wire, and the residual light of the eyes can also see the reverse side of the surplus height, so the weld fusion is good; The negative residual height and infusion can be well controlled. Disadvantages: difficult operation, requires welders to have more skilled operation skills; Due to the large gap, the welding quantity increases correspondingly, the current is low due to the large gap, and the working efficiency is slower than the outer wire filling. 7. Stop arc To stop an arc is to stop halfway for some reason and then continue welding. The correct method of arc stopping is to adopt the method of arc closing after the casting accelerates arc moving speed (reducing the area of molten pool), so that there are no arc pits and shrinkage holes, which creates conditions for the next arc starting to continue welding, and the length of arc accelerating is about 20mm. When using arc welding again, after the formation of the weld pool, press 1-2 ripples backward, the starting point of the joint does not add or less add welding wire, and then into the normal welding, in order to prevent the formation of pores, to ensure the quality of welding seam, the starting point or joint should be appropriately slowed down the welding speed. 8. The arc Arc closing, also known as arc extinguishing, is the necessary way to terminate welding. Arc closure is very important and should be highly regarded. If arc withdrawal is improper, it is easy to cause defects such as arc pit crack and shrinkage cavity. Common arc withdrawal methods include: A. The welding current attenuation method USES the attenuation device to gradually reduce the welding current, so that the melting pool will gradually shrink, so that the base material cannot melt, so as to achieve the purpose of no shrinkage hole at the arc ending. B. Increase welding speed method at the end of welding, welding torch forward speed gradually accelerated, the amount of wire feeding gradually reduced, until the base material does not melt until. The basic point is to gradually reduce heat input, overlap weld 20-30mm. This method is most suitable for circular seam, no arc pit and no shrinkage cavity. C. When the arc extinguishing method is terminated, the welding speed slows down, the welding torch back inclination Angle increases, elongates the arc, makes the arc hot The main concentration is on the welding wire, and the welding wire feed quantity increases, fills the arc pit, and causes the weld seam to increase, after extinguishing the arc immediately to ignite the arc, repeats two or three times, is convenient for the molten pool when solidifying can continue to get the welding wire supply, causes the arc to close the place gradually to cool down. However, after arc extinguishing for many times, the arc closing place is often higher, so it is necessary to flatten the welding seam which is higher at the arc closing place. D. Arc extinguishing plate is often used in flat butt joint of arc extinguishing plate method. After welding, the arc extinguishing plate shall be removed and smoothed. The practical operation proves that the current attenuation method is the best method for arc suppression with an attenuation device, and the increasing welding speed method is the best method for arc suppression without an attenuation device, which can avoid arc pits and shrinkage holes. After arc extinguishing, the torch should not be removed immediately, and should stay at the arc suppression place for 2-5min. The arc suppression place under high temperature should be protected from oxidation by lagging gas.铜焊丝,Copper Welding Rods,铝焊丝,aluminium welding wire,镍焊条,Nickel electrode,药皮焊条,Flux Coated Brazing Welding Rods