Straightness
Straightness depends on the work done by the cold bar producer. But it certainly helps to receive a bar with good metallurgy from the mill.
Hot rolled bars may arrive from the mill with surface defects. Quality Bar has found little correlation between the surface defects and the ability for the bars to be straightened. In most cases surface defects are compensated for in the TGP process. Unfortunately inspection will not detect internal problems and internal problems have a serious affect on the ability to straighten a bar. Higher carbon bars, higher alloy bars and heat treated bars all tend to have greater internal problems than do lower or mid carbon bars and are much more difficult to straighten
Quality Bar monitors the following variables during their straightening process:
All of these variables are interrelated, but there are optimum settings for each depending on the diameter and metallurgy of the bar being processed.
Quality Bar uses PLC to controls many of these variables.
Experience plays an important when the bars have internal problems. At such times it is important to have a trained operator who knows how to make the proper adjustments.
The diameter of the bar is not straightening factor, whereas metallurgy is. Lower carbon bars are the easier to straighten. Higher alloys and higher carbon bars are more difficult. Bars that are improperly heat treated bars are the most difficult.