Shielded Metal Arc Welding (SMAW)

Shielded Metal Arc Welding (SMAW) Overview

• SMAW is also known as shielded metal arc welding.
• SMAW is known as manual metal arc welding.
• SMAW is referred to as flux shielded arc welding.
• SMAW is the most commonly used arc welding process.
• SMAW equipment has a lower cost compared to other methods.
• SMAW is commonly used by mini pros and metalworking businesses.
• SMAW is commonly used for mobile welding jobs.

Electrodes in SMAW

• SMAW uses consumable electrodes.
• Electrodes consist of a filler metal rod, covered in chemicals.
• The chemical covering consists of dark gray and white flux.
• The flux shields the welding area.
• Electrode length is typically 9 to 18 inches long.
• Electrode diameter is 1/16 to 5/16 inches.
• The filler metal in the rod must be compatible with the metal being welded.
• The filler metal is connected to a welding power source.

Welding Machine Components and Operation

• Transformers can be used to change voltage and current to desired levels.
• Selection of the correct electrode type is important for successful welding.
• Polarity is a significant factor in SMAW.
• Straight polarity involves connecting the electrode to the negative terminal, and the workpiece to the positive terminal.
• Reverse polarity involves connecting the electrode to the positive terminal, and the workpiece to the negative terminal.
• The tip of the electrode is brought close to the workpiece to initiate an arc.
• Striking an arc involves briefly touching the electrode to the workpiece and then pulling it back slightly.
• Maintaining a short arc gap is crucial for a stable and effective weld.
• A consumable electrode melts during the welding process.
• A consumable electrode provides filler material for the weld joint.
• A short circuit can occur if the electrode sticks to the workpiece.
• The flux coating on the electrode melts.
• The flux coating forms a shielding gas and slag layer.
• The shielding gas and slag layer protects the molten metal from atmospheric contamination.
• Arc temperatures can reach up to 10,000 degrees Fahrenheit or 5,500 degrees Celsius.

Techniques and Applications

• Different welding styles and maneuvers exist.
• Weld passage must be tested for quality.
• SMAW is good for quick repairs.
• SMAW is often employed in construction.
• SMAW is often employed on pipelines.
• SMAW is often employed for machinery fitting.
• SMAW is often employed in shipbuilding.
• SMAW is often employed in fabrication shops.
• SMAW is suitable for both indoor and outdoor applications.

Advantages and Disadvantages

• SMAW equipment is portable.
• SMAW equipment has a relatively low cost.
• SMAW is generally done on mild steel, low alloy steel, and stainless steel.
• SMAW is often used in instances with ferrous and non-ferrous metals.
• SMAW requires frequent replacement of electrodes due to their consumable nature.
• The need to replace electrodes can increase the welding time.
• Removal of slag is required after each weld pass.
• Slag removal requires additional time and effort.
• The electrode's flux coating generates shielding gas and slag.
• The shielding gas and slag prevent the molten metal from reacting with atmospheric elements.

This lesson covers shielded metal arc welding (SMAW), also known as manual metal arc welding or flux shielded arc welding. SMAW is the most commonly used arc welding process due to its lower equipment costs. It uses consumable electrodes consisting of a filler metal rod covered in flux.