Technology | Hand arc welding double-sided forming six tips and five essentials, easy to remember.

Single side welding double-sided forming technology is a kind of operation technology with large arc difficulty, master the Operation Essentials and skills to ensure the welding and testing of the quality of qualified welds and specimens.

Take the arc welding as an example, to master the welding rod arc welding double-sided forming operation Technology, must master five kinds of essentials, specific content: see, Listen, Quasi, short, control. Also should learn six kinds of skills specific content: Point solid, head, transport bar, arc, joint, close.

One or five essentials 1, see
During the welding process, carefully observe the shape of the molten pool, the melting size and the separation of molten iron and slag, but also to observe whether the welding process is normal (such as partial arc, polarity is correct, etc.), the molten pool generally keep the ellipse is appropriate (round when the temperature is high), The size of the weld to the arc will be both sides of the blunt edge completely melted and deep into each side of the 0.5-1㎜ as well, the weld hole is too large, the back seam is too high, easy to form welding or burning. Melt hole over the hour, prone to non-weld or cold connection phenomenon (easy to crack when bending) when welding must keep the molten pool clear, slag and iron night to separate, otherwise prone to weld and slag and other defects, when the welding rod in the process of partial arc and splash too large, should immediately stop welding, identify the cause, take countermeasures. 2. Listen to
Welding should pay attention to hear the arc breakdown groove blunt side of the pop sound, there is no such sound, indicating that the edge of the groove is not penetrated by the arc, such as continuing to weld forward, it will be suitable for non-welded, bad fusion defects.
3, quasi-
Give the position of iron and the spacing of the strip to be accurate, and make each molten pool and the front of the molten pool overlap 2/3, to maintain the arc 1/3 part in the front of the pool, to heat and penetrate the blunt edge of the groove, only to the position of the iron liquid is accurate, uniform spacing, can make the weld is uniform, neat, beautiful.
4. Short

Short there are 2 layers of meaning, one refers to the arc and re-ignition arc time interval is short, that is, each arc time to select in the molten pool in the semi-solidification melting state (through the eye protection Glass can see Huang Liang), two point breakdown method, the arc frequency is generally 50~60 times/㏕ advisable, if the interval is too long, the pool temperature is The time of the molten pool is short, the metallurgical reaction is not sufficient, and the slag, porosity and other defects are easily caused. The time interval is too short, the dissolved pool temperature is too high, will make the back seam is too large, even appear weld or burn; the second is the welding arc to be short, welding arc length is equal to the diameter of the electrode is appropriate. Arc is too long, one is not good for the protection of the pool, easy to produce pores, the second is the arc penetrating force is not strong, easy to produce defects such as non-penetration; the third is the iron liquid is not easy to control, not easy to form and splash large.

5, Control
  control, is to see, listen, Quasi, short on the basis of the completion of welding the most critical link.
① Control the flow direction of molten iron and dross
The arc should always be in front of the molten iron during welding. The use of the arc and the melt of the gas-directed blowing force, the molten iron into the pool behind the solution, not only to ensure that the slag and iron well separated, reduce the possibility of slag and gas hole, when the iron solution and dissolved slag is not clear, To adjust the angle of the operation bar in time (that is, the electrode angle to the welding direction inclined), and to depress the arc, until the iron and slag distinguish, and both sides of the blunt edge melting 0.5-1㎜ notch can be extinguished, and then normal welding.
② Control the temperature of the dissolved pool and the size of the hole
weld pool shape from oval to circular development, the molten pool becomes larger, and there is a feeling of falling down, such as constantly adding iron, welding meat will not be raised, at the same time there will be larger melting hole, at this time that the molten pool temperature is too high, and slow down the welding frequency (that is, the time of the arc is longer), and so on, after the temperature of the molten pool is lowered, the normal welding is restored.
under the action of high temperature and blowing force of the arc, the root of the test plate groove is melted and penetrated to form a melt hole, the shape of the molten pool should be strictly controlled during the welding process, and the change of the molten pool and the melting condition of the groove root can be observed at any time.
the size of the weld seam determines the width and height of the back, usually the diameter of the hole is greater than the gap 1-2㎜, welding process, such as the discovery of too large, indicating that the molten pool temperature is too high, should be quickly extinguished, and appropriate extension of the arc-extinguishing time to reduce the temperature of the molten pool, and then return to normal welding, Normal soldering can be performed when a suitable weld hole is present.
③ Control welding seam forming and welding meat height
Influence weld forming, the main factors of welding meat high and low are: speed of welding, the amount of deposited metal (that is, the length of arcing time), the front and back position of the electrode, the change of the size of the weld, the length of the arc and welding position. The general rule is: the slower the welding speed, the higher the opposite side of the welding meat; The more the metal is added, the higher the welding meat is, the closer the position of the electrode is to the back of the molten pool, the higher the surface weld meat, the higher the welding meat on the back, and the larger the weld, the greater the welding meat on the back of the seam, the lower the arc pressure, the higher the weld meat on the back. In the position of the pitch, the welding seam on the front of the weld is prone to high welding meat, and welding seam on the back of the meat is prone to low, even appear ... Learn more