Welding mistakes and defects 

Abstract

Key Summary Points

Welding defects can lead to product failure and dangerous operation, making it crucial to identify and repair them.

Universal Technical Institute's 36-week Welding Technology program teaches students how to prevent welding defects and pursue a career in the industry.

Common welding defects include cracks, slag inclusions, porosity, undercut, spatter and overlap.

Repairing welding defects often involves grinding or chipping away the affected area and rewelding with proper techniques.

Prevention of welding defects includes proper pre-heating, removing slag particles, ensuring proper alignment and cleanliness and using the correct welding angle, filler material and shielding gas.

Harms of Welding Defects

Welding mistakes can be hazardous during both manufacturing and servicing. Here are a few reasons why:

Reduced structural strength, resulting in the failure of the welded component, machinery or structure

Increased repair or replacement costs to correct defective parts  

Increased maintenance costs since faulty welds reduce product durability over time

Health and safety hazards since cracks can allow hazardous materials to escape from pipes/machinery and cause structures and materials to fail

Causes of Welding Defects

Defects can occur because of a variety of reasons and can impact the quality and integrity of a welded structure. Identifying their root causes is essential for figuring out effective solutions and ensuring future welds are successful. Below are some common causes of welding defects:

Porosity: Gas pockets become trapped in the weld pool, often due to contaminated materials or insufficient shielding gas.

Cracking: Stresses within the weld metal and heat-affected zone can lead to cracks, typically caused by rapid cooling or improper welding techniques.

Incomplete fusion: When the weld metal fails to properly fuse with the base materials, it’s usually due to inadequate heat input or incorrect welding angles.

Undercutting: Material is melted away from the weld edges, leaving grooves along the weld seam. Can be caused by excessive welding speed or high welding current.

Overlapping: When the weld metal overflows onto the base metal without proper fusion, it’s often due to a too-slow welding speed or excessive welding current.

Slag inclusions: Non-metallic solid materials get entrapped in the weld metal, often caused by improper slag removal between welding passes or inadequate cleaning of the base metal.

Keywords: welding, pipeline, Petroleum industry