Welding technology of small diameter pipe butt horizontal fixed cover surface layer

1. Clean up the slag Carefully clean the slag at the Angle between the bottom weld and the base material on both sides of the groove, and the slag at the superposition of welding spot and welding spot. 2. Shipping method At the position 5-6 o ‘clock of the clock, that is, after the arc is initiated in the inverted welding position, the long arc preheats the inverted welding position, and the first and second molten droplet is thrown off, because the droplet is of low temperature and poor fluidity at this time. Then, the droplet is sent up in a short arc, and the welding is performed by crescent or transverse zigzag moving strip method. The welding process is always kept short arc, welding rod swing to both sides of the pause, the edge of the groove melting 1-2mm, so that the weld metal and the base metal smooth transition, to prevent the occurrence of edge defects. During the welding process, the molten pool should always be elliptical in shape and consistent in size, and the pool should be bright and clear. When the first half circle is closed, it is necessary to fill the arc pit with some molten metal to make the arc pit into a slope shape and create conditions for the end of the second half circle weld. Before welding the second half of the circle, the welding slag at the starting part of the first half of the circle should be knocked off 10-15 mm, and the arc pit should be filled in the end of the weld. When the cover layer is welded with alkaline electrode, short arc preheating and welding are always used. 3. Electrode Angle Because the root bottom weld has been welded, the cover surface weld has nothing to do with whether the root is fully welded, the main technical problem is that the cover surface weld should be formed well, the residual height should meet the technical requirements, the weld and the base metal smooth transition, no bite. Therefore, the Angle between the tangent line of the welding direction of the electrode and the pipe should be about 5° larger than the bottom welding. (1) In the inverted welding position, that is, the position of clock 6-7, the included Angle of the tangent line between the welding rod and the welding direction tube is 85°-90°. (2) In the upward climbing welding position, that is, the position of clock 7-8, the included Angle of the tangent line between the welding rod and the welding direction tube is 105°-110°. (3) The vertical welding position, that is, the clock 9 o ‘clock position, welding rod and welding direction tube tangent Angle is 95°. (4) In the vertical climbing welding position, that is, the position of clock 10-11, the included Angle of the tangent line between the welding rod and the welding direction tube is 90°-95°. (5) Flat welding position, namely 12 o ‘clock position, welding rod and welding direction tube tangent Angle of 75°-80° 4 Steps and precautions 1) Familiar with patterns, clean groove surface and file blunt edges. 2) Assemble the specimen according to the assembly requirements, conduct positioning welding, and fix the specimen horizontally at a height of 800-900mm from the welding bracket to the ground for welding. 3) Start welding from the inverted welding position of the pipe, welding the right half circle counterclockwise first, and welding to the flat welding position by arc breaking method. 4) Clean up the welding slag and grind the joint of the inverted and flat welding position into a gentle slope. 5) Change the welding position, weld the left half circle, start the head at the gentle slope of the upward welding position or use the arc to cut the gentle slope to return the head, and complete the welding of the bottom layer with the same operation method as the right half circle. 6) Clean welding slag and splash, welding cover layer, still adopt two half ring welding method, welding using crescent shape or transverse zigzag strip welding, pay attention to fill arc pit during arc closing. 7) After welding, clean up the welding slag and spatter of the inner and outer welds of the pipe fitting, and check the welds on the front and back sides.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