Amid processing of a honed tube, pits on the surface of honed tube are a key factor reducing quality of a finished tube. To get a qualified honed tube, such flaws must be repaired. Here are solutions,
1. Choose qualified hot-rolled raw material.
This is a process control of raw material. Since the pits on a cold-drawn tube results from the hot-rolled one, it can be reduced by choosing a hot-rolled tube of low rust and even thickness and the finished rate can be increased accordingly;
2. Treatment of cleaning the interior hole of a hot-rolled tube.
As prestige says, as some developed countries like Japan, UK, Germany and so on already do, if measures of crack detection and flaw cleaning of interior surface is taken before cold drawing of a hot-rolled tube, it can be assured that flaw of pits won’t happen in the cold-drawn one, thus enabling smaller working allowance, reducing cost of production and increasing productivity;
3. Increase scale of cold-drawing and volume of deformation.
To reduce the honing allowance so as for the target of reducing flaw of pits, the times of cold-drawing deformation during processing of a honed tube can be increased, thus obtaining a large aggregate volume of deformation.
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