The welding deformation of the boom is mainly caused by improper welding methods.

Depending on different materials and thicknesses, the selection of welding wire, current, and voltage are also different.

The boom is a thin box structure. When welding, deformation should be considered first, and segmented symmetrical welding is generally adopted.

At the same time, use reinforcing ribs to reduce welding deformation. After welding is completed, heat treatment (stress annealing) is required. After heat treatment, the reinforcing ribs can be removed only after being stored at room temperature for 24 to 48 hours.

Welding process parameters are shown in Table 1 and Table 2

Table 1: Φ1.2 wire CO2 butt welding process parameters

Joint form, plate thickness, number of layers, welding current (A) Arc voltage (V) Welding wire extension (mm) Welding machine speed m/min Gas flow rate L*min Assembly gap (mm)

6 1 270 27 12-14 0.55 10-15 1.0- 1.5

6 2 190-210 19-30 15 0.25 15 0-1

8 2 120-130130-140 26-27 28-30 15 0.55 20 1-1.5

10 2 130-140280-300 20-30 30-33 15 0.55 20 1-1.5

10 2 300-320300-320 37-39 37-39 15 0.55 20 1-1.5

12 310-330 32-33 15 0.5 20 1-1.5

16 3 120-140300-340300-340 25-2733-3535-37 15 0.4-0.50.3- 0.40.2-03 20 1-1.5

16 4 140-160260-280270-290270-290 24-2631-3334-3634-36 15 0.2-0.30.33-0. .5-0.60. 4-0.5 20 1-1.5

20 4 120-140300-340300-340300-340 25-2733-3533-3533-37 15 0.4-0.50.3-0.4 20 4 140-160260-280300- 320300-320 24-2631-3335-3735-37 15 0.25-0.3 0.45-0.5 20 1-1.5

Table 2: Φ1.2 wire CO2 gas shielded welding T-shaped joint

Joint form plate thickness (㎜) Welding wire diameter (㎜) Welding current (A) Arc voltage (v) Welding speed (m/min) Gas flow (L/min) Welding fillet size (㎜)

2.3 Φ1.2 120 20 0.5 10-15 3.0

3.2 Φ1.2 140 20.5 0.5 10-15 3.0

4.5 Φ1.2 160 21 0.45 10-15 4.0

6 Φ1.2 230 23 0.55 10-15 6.0

12 Φ1.2 290 28 0.5 10-15 7.0

There are no drawings of the boom.