What can affect the width of the weld bead?
It is found that bead width is affected by the electrode polarity, electrode diameter, electrode extension, welding current, welding voltage and welding speed. A positive electrode polarity, a large electrode diameter, a small electrode extension and a high welding voltage encourages a large bead width in most cases.
What increases the bead width?
The bead width increases with increase in wire diameter and voltage. The maximum bead width is obtained with 3 mm wire diameter at 36 V voltage while minimum bead width is obtained at 28 V voltage with 1 mm wire diameter.
What causes wide bead in welding?
Wire feed speed/amperage too high – Setting the wire feed speed or amperage too high (depending on what type of machine you’re using) can cause poor arc starts and lead to an excessively wide weld bead, burn-through and distortion.
What should be the width of a weld bead?
This helps to minimize distortion by limiting the volume of weld metal and reducing the heat input. The maximum bead width should be limited to 3/8 in. (10 mm). As a minimum, one complete circumferential bead should be completed before stopping or interrupting the welding sequence.
When comes to a good weld the width of bead should be?
Keep the electrode wire directly in front of the center of the pool. A good weld bead should have evenly spaced ripples. The edges of the weld should be the same width. There should be about 1/16″–1/8″ (1.6 mm–3.2 mm) of reinforcement.
What causes slag inclusions?
Slag inclusions are nonmetallic particles trapped in the weld-metal or at the weld interface. Slag inclusions result from faulty welding technique, improper access to the joint, or both. … Dipping the tungsten electrode in the molten weld-metal or using too high current that melts the tungsten can cause inclusions.
How is the electrode size identified?
The electrodes are also specified based on the ratio of the diameter of the coated portion of the electrode to core wire diameter. If the ratio is less than 1.2 then electrodes are thin coated. … If the ratio exceeds 1.5 then electrodes are heavy-coated or thick coated.
What is weld bead characteristics?
13 Weld Bead Appearance Two characteristics of the weld bead are the bead height and width, as shown in Figure 7-13. These characteristics are important to assure that the weld joint is properly filled, with a minimum of defects, particularly in multi-pass weldments.
What are the 12 most common discontinuities?
What Are Some Common Welding Discontinuities?
- Porosity. Porosity occurs when gas becomes trapped in the weld pool, forming permanent bubbles as the metal cools from a liquid state back to a solid. …
- Inclusions. …
- Inadequate Joint Penetration. …
- Incomplete Fusion. …
- Arc Strikes. …
What is excessive convexity in welding?
This condition is usually caused by excessive welding current or arc lengths. Excessive Convexity –This discontinuity can produce a notch effect in the welded area and, consequently, stress concentration under load. For this reason, some codes and standards will specify the maximum convexity of a weld profile.
What is the minimum weld size?
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How do you define weld size?
The length of the leg is usually referred to as the size of the weld. The weld throat is the distance between the center of the face and the root of the weld. Usually, the depth of the throat must be at least as thick as the thickness of the metal you weld.
What is the correct motion for cutting?
The knife should perform a rocking motion during cutting: the front top portion of the blade should stay on the cutting board during all times when cutting (or at least the majority of the cutting time), and the rest of the blade should go up and down.