1 preparation

By drawing on the raw materials and drawing lines, and cut into a certain shape and size. Note to select the appropriate connector type, when the workpiece thick, the joints must also be processed into the shape of the groove.

(2) the choice of welding specifications

Arc welding electrode specification, mainly the type of welding current and electrode diameter size choice. According to the welding electrode workpiece material selection grade, as the welding speed and arc length, usually by Welding Electrode grades and according to the location of the weld where the space in the welding process appropriate adjustments.

(1) electrode diameter

To improve productivity, thick electrode diameter is usually used, but generally not more than 6mm. Workpiece thickness of 4 mm below the butt welding, generally equal to the workpiece with a diameter less than the thickness of the electrode. Refer to Table 4.1. Large thickness of the workpiece during welding, the general groove joints should, play in the bottom of welding, soldering, can be 2.5 ~ 4mm diameter electrode, the layers can be used after 5 ~ 6 mm diameter rod. Vertical welding, the electrode diameter of not more than 5 mm; Yang welding should not exceed 4 mm.

Weldment thickness / mm
 <4
 4 to 8
 9 to 12
 > 12
 
Electrode diameter / mm
 ≤ thickness
 φ3.2 ~ 4
 φ4 ~ 5
 φ5 ~ 6
 

(2) The welding current

The size of the welding current is determined primarily on the basis of electrode diameter. Welding current is too small, low productivity, welding, arc of instability, and may not weld through the workpiece. Welding current is too large, it will cause serious molten metal splash, and even burn the workpiece.
For welding general steel work piece, electrode diameter 3-6mm, the following empirical formula obtained by the welding current reference value:

                           I = (30-55) d

                            I - Welding current (A);

                            d - electrode diameter (mm);

           
In addition, the current size of the selection, with every joint type and Nickel Alloy Welding Electrodes position in space and other factors. Vertical welding, horizontal welding welding welding current level should be reduced more than 10 - 15%; overhead position welding is reduced by 15 - 20%.

3. Weld layers

Weld layers depending on the thickness of the weldment. In thick multi-layer welding is generally used. More weld layers, will help improve the ductility of weld metal toughness. Requires high quality welds on each layer thickness preferably not more than 4 ~ 5mm. Figure 4-8 shows the multi-layer welding of the weld, the welding sequence number in accordance with the plans for welding.

4 the spatial location of the weld

Based on the location of the weld in space is different from a flat welding, vertical welding, horizontal welding and overhead position welding of four, as shown in Figure 4-11. Flat welding easy to operate, working conditions, high productivity, easy to weld quality assurance, so arranged as far as possible on the flat seam welding position. Vertical welding, horizontal welding and overhead position welding, due to gravity, is the molten metal to drip down the difficulties caused by welding, therefore, should be avoided.