Do I need a Straightener and a Leveler?
Misconception: It is relatively common to see some lines incorporating both a Straightener and a Leveler while other systems use only a Leveler. What’s the difference?
Clarification: The practice of using both a Straightener and a Leveler in the same line varies from manufacturer to manufacturer. Typically, if both machines are used, the manufacturer will contend that by using a Straightener to remove coil set prior to leveling, better flatness can be achieved.
Manufacturers that use only the Leveler maintain that when the strip is leveled, coil set is also removed as a consequence of the process and prior removal has negligible benefits.
Because the coil set in the material constantly changes throughout a coil, as with a Straightener, the first group of work rolls in a Leveler are actually used to induce reverse coil set into the strip.
This reverse set is constant, which the remaining rolls can flatten without constant roll adjustment. This basic principle of operation eliminates the necessity to precondition the strip.
Summary: In regards to effectiveness, either line configuration will produce satisfactory results. However, most equipment manufacturers that actually produce a Leveler state that prestraightening is not required.
Conclusion: Although most misconceptions are based on assumptions and misinterpreted information, they are often perceived as being fact. However, by reviewing the surrounding information more closely, most can be explained.