welding rods

Welding arc is observed in the mask and operate. As the poor visibility, poor working conditions. Therefore, to ensure the welding quality, not only requires a more skilled technique, but also high concentration of attention. For beginners to practice should pay attention to: current to the right, to be on the positive electrode, the arc is shorter, faster welding speed should not strive evenly.

    Before welding, the workpiece should be 20mm wide joints on both sides of the surface clean (remove rust, oil, water), and to the ends of the core metal electrode exposed for short arc. Arc method percussion and friction and French law; the friction law is easier to grasp, suitable for beginners arc operation.

1 arc

  (1) scratch method — the first electrode weldments aligned, and then draw a match like as electrodes in welding lightly scratch the surface, ignite the arc, and then quickly lift the rod 2-4mm, and make stable combustion,

  (2) percussion method — the end of the rod aligned weldment, then the wrist the next bend, slight electrode touching the weldment, and then quickly lift the rod 2 ~ 4mm, flat wrist after arc ignition, the arc to keep stable combustion. This method does not make arc welding surface scratches, but also from the surface of weldment size, shape constraints, it is used in the production of the main arc method. But the operation is not easy to master, need to improve proficiency.
  Arc should pay attention to the following matters:

  1) The arc should be no oil, water, rust, to avoid porosity and slag.

  2) electrode in contact with the welding conditions should be appropriate to enhance the speed, fast hard arc, slow welding wire and pieces of stick together causing a short circuit.

2. Transport of

Operation of the welding process is the most important part, it directly affects the appearance of the weld shape and internal quality. Arc ignition, the general case there are three basic movement electrodes: the direction toward the pool gradually admitted, gradually moved along the welding direction, horizontal swing.

Direction toward the bath electrode gradually sent to the pool to add — both metal and to melt the electrode to continue to maintain a certain arc length, so the electrode and the electrode should be sent to the rate of melting at the same speed. Otherwise, stick place in the welding arc or broken pieces.

Moves along the welding electrode rod — With the continuous melting, and gradually form a weld. If the electrode moves too slow, then the bead will be too high, too wide, irregular shape, burn occurs when welding sheet metal phenomenon; if the electrode moving too fast, then the electrode and the weldment will melt unevenly, weld narrow, or even lack of penetration phenomenon. Electrode should be moving forward with an angle of 70-80 degree angle, so that the molten metal and slag into the rear, or front of the arc slag flow, will result in defects such as slag.

— For the lateral electrode welding pieces of input swing enough so that the exhaust heat, slag, and get a certain width of the weld or weld. Swing range of electrode thickness under the weldment, groove form, weld layers and electrode diameter to decide.

Commonly used methods and scope of operation:

(1) linear operation of the law — using this method of operation of the welding, the electrodes do not do horizontal swing, a straight line along the welding direction of the move. Commonly used in the I-shaped groove butt-welding, welding of the first multi-layer or multi-layer welding multi-pass welding.

(2) reciprocating operation of the law — using this method of operation of the welding, the welding seam along the longitudinal Moduan do swing back and forth. It is characterized by a welding speed, narrow weld, heat quickly. For sheet metal and welded joint gap of the first large multi-layer welding.

(3) operation of law — serrated using this method of operation of the welding, the electrodes do not end a continuous zigzag swing and move forward, and pause a moment on both sides, swing in order to control the flow of molten metal and the necessary weld width to get a better weld. This method of operation used widely in production, used for thick steel plate welding, flat welding, Yang welding, vertical welding of butt joints and vertical welding of corner joints.

(4) crescent-shaped operation of law — using this method of operation of the welding, the electrode end

Along the welding direction to do crescent-shaped swing. Swing speed, according to the location of the weld, joint form, weld width and weld current to decide. Joints on both sides of the same time need to stay a moment to do this is to make the edge of the weld penetration enough to prevent the biting edge. This method has the advantage of operation of a good metal melting, a longer holding time, the gas easily precipitate, slag is easy to float up to the surface of the weld, the weld quality high, but out of the weld reinforcement welding high . This method of operation of the application and operation of serrated basically the same.

(5) — triangle operation of the law using this method of operation of the welding, the electrode end of the triangle to do a continuous movement, and continue to move forward, according to the different forms of swing, triangle and oblique triangle can be divided into two, oblique operation of law applies to triangular flat welding position welding and overhead position welding T-joint weld and cross weld groove, the advantage is the ability to swing through the electrode to control the molten metal, to promote good weld. Triangle law applies only to transportation of open groove butt joints and T-shaped connector weld vertical welding, a weld can be characterized by a thick section welds, weld slag and other defects is not easy to produce, will help improve production efficiency.

(6) circle-shaped operation of law — using this method of operation of the welding, the electrode end of the row to do is circle or circle-shaped oblique movement, and continue to move forward, is a circle-shaped transport method for welding thick section weldments flat weld pool there is the advantage of a long time, high temperature metal bath, in favor of oxygen dissolved in the bath, the precipitation of nitrogen and other gases, easy slag floating. Oblique circle graph for level operation of law, Yang T-joint weld location and cross-weld butt joints, the advantage is not conducive to control the molten metal produced under the influence of gravity drip phenomenon, contributing to weld.
3. Weld finishing

Weld finishing, in order to not appear the end of pit, welding rod should stop moving forward, while the use of circle arc finishing off method or the method repeatedly, slowly pull off the bottom arc, forming the tail to ensure a good weld.

(1) circled finishing method — the end of the weld electrode to move when using the wrist action to do a circle motion, until it fills the crater and then pull off the arc. The method is suitable for thick plate welding, sheet metal welding will be used to burn hazard.

(2) repeatedly broken arc method — the end of the weld rod to move, in the crater at the repeated extinction, arc several times, until it fills the crater so far. The method is suitable for welding thin and high current, but not for basic welding rod, or will cause porosity