What is the basic operation method of 2. Welding?

Second, welding. The basic modus operandi is:

1. The joints with bevels in vertical or inclined positions must be welded from bottom to top, and the butt butt and vertical fillet welding of thin plates without bevels can be welded downward; Flat, horizontal and vertical butt joints can be welded in the left direction.

2. When the wind speed is greater than 1m s in outdoor operations, windproof measures should be adopted.

3. A reasonable welding sequence must be selected according to the structure of the workpiece to be welded.

4. Arc striking and arc extinguishing plates of appropriate size should be set at both ends of the butt.

5. The dirt in the hose and the splash of the nozzle should be cleaned frequently.

6. For plate seams with grooves, especially for multi-channel welds of thick plates, the welding wire should stay on both sides of the groove when swinging, and the thickness of each layer of the zigzag transport strip is not more than 4mm, so that the weld is well fused.

7. Correctly select the wire contact tip according to the diameter of the welding wire, and the length of the welding wire should generally be controlled within the range of 10 times the diameter of the welding wire.

8. When the wire feeding hose is welded, it must be smoothed and not coiled, and the radius of the wire feeding hose is not less than 150mm. The remaining impure gas in the gas supply hose should be discharged before welding.

9. The aperture increases after the contact tip is worn, which causes the welding to be unstable, and the contact tip needs to be replaced.

The principle of the second welding is that the welding wire and the weldment are used as two electrodes to generate an electric arc, and the heat of the arc is used to melt the metal, and carbon dioxide gas is used as the shielding gas to protect the arc and the molten pool, so as to obtain a good welding joint.

1. The full name of the second protection welding is: carbon dioxide gas shielded welding, which is a welding method.

2. This welding method has become one of the most important welding methods for ferrous metal materials.

3. Features: 1) Low welding cost. Its cost is only 40 50% of submerged arc welding and electrode arc welding.

2) High production efficiency. Its productivity is 1 4 times that of electrode arc welding.

3) Easy to operate. Open arc, no limit to the thickness of the workpiece, can be welded in all positions and can be welded downward.

4) High crack resistance of welds. The weld is low in hydrogen and also has less nitrogen.

5) The deformation after welding is small. The angular deformation is 5 thousandths, and the unevenness is only three thousandths.

6) Small welding spatter. Welding spatter can be reduced when ultra-low carbon alloy or flux-cored wires are used, or AR is added to CO2.

Second, the welding is carbon dioxide protection welding.

Carbon dioxide is used as the shielding gas for welding.

Welding wire is used.

The weld is well formed.

1. Whether the weld of the object is cleaned, because many times, the weld is very dirty, including iron oxide, welding slag shell, iron oxide rust on the base metal, etc., try to clean it to ensure the welding quality.

2. Clean the nozzle of the second welding torch, and do not bend the wire feeding tube too much to ensure that the wire tip is smooth to avoid affecting the current and voltage.

3. Carbon dioxide gas is sufficient. Try to avoid wind sources to avoid air holes.

Left welding method (right left), right welding method (left right), or which gun method, flat angle welding does not swing or small swing, vertical angle upward welding, and the use of triangular gun transport is the five methods of two protection welding. The welding torch transitions, stay on both sides of the molten pool, and transition in 1 3 places before the molten pool. The angle of the gun, the vertical annihilation regiment is more than the weld bead, and it is at an angle of 80-90 ° along the direction of the gun.

Test board: gap, the starting point is slightly smaller than the closing point. No blunt edges, reverse deformation 1°.

Second, the welding machine starts the arc

1) Keep the dry elongation not rolling.

2) Backward arc striking method, arc striking at the front end of the weld bead 10-20mm.

3) The joint is thinned to prevent the joint from not melting.

Second, the welding machine closes the arc

1) Keep the dry elongation unchanged.

2) Arc closing at the edge of the melt pool.

Although the arc starting and closing process of CO2 is simple, it is necessary to master the standardized operation process if it meets certain quality requirements.

Arc starting process: Before arcing, press the welding torch switch when maintaining a certain distance between the end of the welding wire and the base metal.

During arcing, keep the dry extension length stable. Due to the low temperature of the workpiece at the arc starting, and the arc cannot be elongated and preheated like manual welding, the backward arc approach method should be used to fully melt the weld bead.

Arc closing process: When CO2 welding arc receiving, the dry elongation length should be kept unchanged, and the burning point should be pulled to the edge of the molten pool to stop the arc, and the welding machine will complete the arc closing process of reburning, ball elimination and delayed gas protection.

Welding Method:

1) Left welding method (right left).

2) Right welding method (left right).

3) Gun transport method.

4) Flat fillet welding does not swing or swings slightly.

5) Vertical angle upward welding, using triangular gun transport.

6) Welding torch transition: stay on both sides of the molten pool, and transition in 1 3 places before the molten pool.

7) Gun angle: perpendicular to the weld bead, at an angle of 80-90° along the direction of the gun.

8) Test board: gap, the starting point is slightly smaller than the closing point. No blunt edges, reverse deformation 1°.

Pay attention to the combination of current and voltage, not pull welding, should push welding, so as to increase the tensile strength.