Welding process using welding rods

The complete process of electrode welding can be broken down into five key stages. Let me explain them clearly for you:

I. Arc Initiation
Operation: The electrode briefly contacts the workpiece and is then quickly pulled away or struck against it to generate a stable arc.
Methods:
Tapping method: The electrode is dropped vertically to strike the workpiece, creating a short circuit before being lifted to generate an arc. This method is suitable for various positions.
Scratching method: The electrode slides on the bevel before being lifted. This method is easy to master but may damage the workpiece.
Technique: The arc initiation point should be 10mm from the starting point of the weld seam. After preheating, move to the starting point. For acidic electrodes, the arc length is approximately equal to the electrode diameter; for basic electrodes, the arc length is half the diameter.
II. Arc Heating
Process: The high-temperature arc (5000-8000K) simultaneously heats the electrode tip and the workpiece's welding area.
Function: The electrode core and a portion of the workpiece melt, forming a molten pool.
III. Melting and Molten Pool Formation
Melting: The electrode core and the workpiece are melted by the arc heat, forming a molten pool.
Protection: The electrode coating melts, producing gas and slag, protecting the molten pool from air intrusion.
Metallurgical reaction: The slag reacts with the molten metal, refining the weld metal.
IV. Molten Pool Solidification
Process: As the electrode moves, the molten pool metal cools and solidifies, forming a weld seam.
Influencing factors: Electrode movement speed, arc length, welding current, etc.
V. Weld Seam Formation
Result: After solidification, a welded joint with certain strength and properties is formed.
Characteristics: Flexible operation, strong adaptability, suitable for various positions and irregular welds.
Other Key Points
Equipment: AC arc welding machine (low cost but poor arc stability) and DC arc welding machine (stable output but complex structure).
Parameter control: Too little current can lead to incomplete fusion, while too much current can cause spatter; the arc length is usually 1/2 to 1 times the electrode diameter.
Operation: Arc initiation, three movements of the electrode (feeding/longitudinal movement/lateral oscillation), and finishing techniques to prevent cracking.