Thickness Measurement of Blast Furnace Staves with Curved Cooling Channel Using a Specially Designed Ultrasonic Probe

Blast furnaces in steel industries employ staves, which provide cooling to the furnace shell for maintaining structural integrity. Motion of the raw material within the furnace during operation causes the cooling staves to wear. Thickness of the staves needs to be monitored on a regular basis to avoid catastrophic failure. The staves of the furnace in question have a curved cylindrical cooling channel as opposed to straight cooling channels; which makes the thickness measurement particularly challenging in this case due to mode conversion. Ultrasonic based thickness measurement is a widely used technique in industries for stave thickness measurement. This text describes a unique modification in a conventional ultrasonic probe to measure the thickness of the staves with curved cooling channels. The modified probe is designed to avoid mode conversion due to incidence of ultrasound at oblique angles. FEM simulations were done to validate the effectiveness of the shoe followed by trials in actual furnace.