Weld cracking and types of cracking

  • Weld cracking and types of cracking

    Posted by NDT-Inspect on 06/01/2023 at 11:02 am

    Weld cracks can form due to a variety of factors, including:

    • Poor design of the welded joint: If the welded joint is not properly designed to handle the stresses it will be subjected to, it can be more prone to cracking.

    • Improper welding techniques: If the welding process is not performed correctly, it can result in weld cracks. This can be due to improper preheat and interpass temperatures, incorrect filler metal selection, or inadequate joint preparation.

    • Incompatible materials being welded together: Welding together materials with different mechanical properties or melting points can lead to weld cracking.

    • Presence of contaminants in the weld area: Contaminants such as oil, grease, and rust can weaken the weld and make it more prone to cracking.

    • Temperature changes during welding: If the temperature of the welded joint changes too quickly during welding, it can cause the metal to contract and crack.

    • Residual stress from previous welds or other processing: If a welded joint has been subjected to high levels of stress in the past, it can be more prone to cracking when welded again.

    • There are several different types of weld cracking, including:

      1. Hot crack: A hot crack occurs while the weld is still cooling, and is usually caused by the presence of high residual stresses or the use of incompatible materials.

      2. Cold crack: A cold crack occurs after the weld has cooled and is usually caused by the presence of tensile stress in the welded joint.

      3. Underbead crack: An underbead crack occurs in the weld metal below the surface of the weld, and is usually caused by the presence of hydrogen in the weld metal.

      4. Lamellar tear: A lamellar tear is a type of weld cracking that occurs in the heat-affected zone (HAZ) of a welded joint, and is usually caused by the presence of tensile stress in the HAZ.

      5. Root crack: A root crack occurs at the root of a welded joint and is usually caused by the presence of tensile stress or the use of incompatible materials.

      6. Intergranular crack: An intergranular crack occurs along the grain boundaries of the weld metal and is usually caused by the presence of tensile stress or the use of incompatible materials.

    NDT-Inspect replied 3 weeks, 6 days ago 1 Member · 0 Replies
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