Operation control and connectors
welding parameters
4.6 Welding parameters
4.6.1
Joint form in MMA
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In MMA welding, the common basic joint form: butt joint, lap joint, corner joint & T joint.
4.6.2
Electrode selection
The electrode diameter selection is based on the workpiece thickness, welding position, joint form,
welding layer, etc. Please refer to the following table.position, electrode spec, welding current and
operation skill, etc.
butt joint
lap joint
corner joint
T joint
The welding current reference for different electrode diameter
Electrode
diameter/mm
Welding current/A
1.6 2.0 2.5 3.2
25~40 40~60 50~80 100~130
The relation between the welding current(I)’ factor(K) & electrode diameter(d) (I
＝
K×d: Carbon electrode)
Electrode
diameter/mm
Factor/K
1.6 2~2.5 3.2
20~25 25~30 30~40
Ÿ
Electrode should be drying according to user manual before using. For reducing the hydrogen of the
molten pool and welding seam, and avoiding the blowhole and cold crack.
Ÿ
In the welding process, the arc must not be too long; otherwise, it will cause unstable arc burning, large
spatter, light penetration, undercut, blowhole, etc. If the arc is too short, it will cause electrode stick.
Ÿ
In MMA welding the arc length is usually equal to 0.5~1.0 time of the electrode diameter. The basic
electrode’s arc length is not beyond the electrode diameter, it’s better to choose the short arc welding;
the acid electrode’s arc length is equal to the electrode diameter.
