A machine used in rolling mills to level the surface of sheet steel. Straightening machines are divided into roll-type machines, which are the most common type, and stretching machines. Roll-type straightening machines are designed for straightening thin and thick sheets in either the cold or hot states; stretching machines are designed mainly for cold straightening of thin sheets (steel and nonferrous metals) of which stringent quality requirements are made.
The rate of straightening is 0.1-6.0 m/sec, depending on the thickness of the sheet.