456A SMAW Stick 2 — Questions and Answers
Question 1: What is the recommended arc length for general SMAW welding?
- As long as possible for better visibility
- Approximately equal to the diameter of the electrode core wire (Correct answer)
- At least 25 mm (1 inch) from the workpiece
- Zero — the electrode should always touch the workpiece
Correct answer: Approximately equal to the diameter of the electrode core wire
The correct arc length for SMAW is approximately equal to the diameter of the electrode core wire (e.g., about 3.2 mm for a 3.2 mm electrode). Too long an arc causes porosity, spatter, and loss of shielding. Too short an arc can cause the electrode to stick, and may result in an inconsistent bead or short-circuiting.
Question 2: What causes porosity in a SMAW weld?
- Using too high an amperage
- Gas entrapment from moisture in electrodes, contaminated base metal, too long an arc length, or wind blowing away shielding gas (Correct answer)
- Using too small an electrode
- Welding too slowly
Correct answer: Gas entrapment from moisture in electrodes, contaminated base metal, too long an arc length, or wind blowing away shielding gas
Porosity (gas pockets in the weld metal) in SMAW is caused by: moisture in the electrode coating (especially low-hydrogen types), contaminated or wet base metal, excessive arc length (allows atmospheric contamination), drafts disrupting the shielding gas, and improper welding technique. Prevention focuses on dry electrodes, clean base metal, and proper arc length.
Question 3: When welding in the vertical-up position with E7018, what technique is commonly used?
- A fast straight-line drag technique
- A weave pattern (triangle, J, or zigzag) with pauses at the toes to allow proper fusion and build-up, using lower amperage than flat position (Correct answer)
- The same technique as flat position with no modifications
- A downhill technique at maximum amperage
Correct answer: A weave pattern (triangle, J, or zigzag) with pauses at the toes to allow proper fusion and build-up, using lower amperage than flat position
Vertical-up welding with E7018 typically uses a weaving technique (triangle, J-weave, or zigzag pattern) with deliberate pauses at the toes (edges) of the weld to ensure proper fusion with the base metal. Amperage is reduced 10-15% compared to flat position to control the puddle against gravity.
Question 4: What is undercutting in a weld and what causes it?
- Weld metal that extends below the root of the joint
- A groove melted into the base metal at the toe of the weld that is not filled by weld metal; caused by excessive amperage, incorrect angle, or excessive travel speed (Correct answer)
- Excess weld metal on top of the joint
- A crack running parallel to the weld
Correct answer: A groove melted into the base metal at the toe of the weld that is not filled by weld metal; caused by excessive amperage, incorrect angle, or excessive travel speed
Undercut is a groove or channel melted into the base metal along the toe (edge) of the weld bead that is not filled by weld metal. It reduces the cross-section of the base metal, creating a stress concentration. Common causes include excessive amperage, improper electrode angle, excessive travel speed, or incorrect weaving technique.
Question 5: What determines the correct amperage setting for a SMAW electrode?
- Only the thickness of the base metal
- The electrode diameter, type, position, and joint design — manufacturers provide recommended ranges for each electrode size (Correct answer)
- The length of the welding lead
- Only the welder's personal preference
Correct answer: The electrode diameter, type, position, and joint design — manufacturers provide recommended ranges for each electrode size
Correct amperage depends primarily on electrode diameter (larger = more current), electrode type (coating characteristics), welding position (reduced for vertical and overhead), and joint design. Manufacturers specify amperage ranges for each size. A common rule of thumb for mild steel is approximately 1 amp per 0.001 inch of electrode diameter.
Question 6: What is slag inclusion and how is it prevented?
- Slag floating on top of the weld — a normal condition
- Non-metallic material trapped within or between weld passes; prevented by thorough interpass slag removal, proper electrode angle, and adequate amperage (Correct answer)
- A type of surface rust on the weld
- Excess flux remaining on the electrode
Correct answer: Non-metallic material trapped within or between weld passes; prevented by thorough interpass slag removal, proper electrode angle, and adequate amperage
Slag inclusion occurs when slag from the flux coating becomes trapped in the weld metal or between weld passes. Prevention requires: thorough removal of all slag between passes using a chipping hammer and wire brush, maintaining proper electrode angle to allow slag to float to the surface, using adequate amperage, and correct travel speed.
456A SMAW Stick 2
What is the recommended arc length for general SMAW welding?