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Steel Defect Terms
Anomalies:
Anomalies are any deviation from a desired or specified characteristic in a steel sheet or plate. They can be structural, such as lack of thickness, curvature or a notch in a steel sheet, or mechanical, such as cracks, blow holes or a tears. Anomalies can be caused by the production process, material handling, transport or storage.
Blowholes:
Blowholes are cavities or depressions in the steel sheet or plate due to the entrapment of gas in the steel. They are caused by the presence of contaminants in the molten steel, such as hydrogen, which form bubbles in the steel as it is being cooled. Blowholes are considered to be a major steel defect, as they weaken the steel and can cause it to fail prematurely.
Burr:
A burr is an uneven surface or raised edge that is caused during the manufacturing of steel sheets or plates. It is usually the result of excessive cutting or grinding of the steel, and can result in imperfections in the finish of the steel. It is usually removed during the inspection process.
Cavities:
Cavities are defects caused by dirt or foreign matter in the molten steel which are not completely removed during the process. As the steel is cooled, these foreign particles cause pockets or cavities in the finish of the steel. Cavities can be located anywhere in the steel, and can range from small pinholes to large holes.
Cracking:
Cracking is the splitting of a steel sheet or plate along its length or width. It is caused by inadequate fusing during the manufacturing process, by defects in the base material, or by irregularities in the steel sheet or plate. Cracking can be a major defect, as it weakens the steel and can reduce its load bearing capabilities.
Laps:
Laps are defects which occur when two pieces of the same sheet fail to join and gaps form between them. This is caused by impurities in the steel, such as dirt and foreign matter, which prevent the steel from melting properly and forming a complete sheet. Laps can be located anywhere in the steel and can be small or large.
Necking:
Necking is a defect in which the steel specifies a change in thickness across a small area. Necking is caused by uneven cooling during the manufacturing process, or by irregularities in the steel sheet or plate. It can result in weaker and less durable steel, and may result in early failure in load bearing applications.
Pin Holes:
Pin holes are small holes or voids in the steel sheet or plate caused by foreign matter or air bubbles trapped in the steel which are not completely removed during the manufacturing process. Pin holes are typically round in shape, and can be found anywhere on the steel. They are considered to be a major defect, as they can weaken the steel and reduce its load bearing capabilities.
Rough Surface:
Rough surface is an uneven finish on the steel sheet or plate which is caused by inadequate grinding or milling during the manufacturing process. It can reduce the effective load bearing capabilities of the steel, as the uneven finish weakens the steel and allows dirt and contaminants to enter the steel.
Scabs:
Scabs are small pieces of slag or foreign matter which are attached to the surface of the steel. They are typically caused by improper cleaning of the steel before and during the manufacturing process, and can reduce the effective load bearing capabilities of the steel by providing uneven surfaces which are prone to corrosion.
Stain Streaks and Checks:
Stain Streaks and Checks are small, dark-colored marks or streaks on the steel sheet or plate caused by impurities or foreign matter in the steel which was not properly cleaned during the manufacturing process. They can weaken the steel and reduce its load bearing capabilities significantly.
Tears:
Tears are defects which occur when the steel sheet or plate is fractured along its length or width due to insufficient welding or impurities in the steel. They can reduce the effective load bearing capabilities of the steel, as the tear will reduce the overall strength of the steel.
Voids:
Voids are defects which are caused by air bubbles in the molten steel which are not completely removed during the manufacturing process. Voids can reduce the effective load bearing capabilities of the steel, as they are weaker spots which are more prone to damage and failure.
