Non‑destructive testing (NDT) plays a vital role for steel quality control. Without destroying raw material, NDT detects internal and surface hidden defects, avoiding defective material flowing into equipment manufacturing. Here we introduce four widely‑used NDT methods for steel bar, pipe and plate.
UT‑Ultrasonic Testing Ultrasonic wave detects internal defects like internal cracks, inclusions and laminations inside steel. Widely applied for seamless pipe, heavy wall tube and large‑size steel bar. Mainly check subsurface and inner‑material quality.
PT‑Penetrant Testing Penetrant testing finds open surface defects such as surface cracks. Suitable for all non‑porous metal surface, good for complex‑shape components. It can only catch defects open to outer surface.
MT‑Magnetic Particle Testing Magnetic particle test works for ferromagnetic carbon steel and low‑alloy steel. It spots near‑surface cracks. Not applicable for non‑magnetic stainless steel or nickel‑base alloy.
ET‑Eddy Current Testing Eddy current test is commonly used for thin‑wall tubes, fast‑check surface and near‑surface imperfections in mass production.
