Steel pipe cold drawing will appear pitting problem, pitting, also known as pitting surface, pit, is the surface of the steel pipe into pieces of fine pitting pits, local or continuous on the surface of the steel pipe. So what causes this problem and how can we prevent it?
Causes of pitting on steel pipe:
1, steel pipe in the heat treatment caused by excessive thickness of the oxide sheet, in the straightening of the oxide sheet pressed into peeling after the production of pitting.
2. There is dirt in the residual iron oxide or saponification solution after pickling, which produces pitting after pulling.
3, after pickling steel pipe, parking time is too long, resulting in rust surface.
4. There is oil on the surface of the steel pipe, and the oil points coalesce during heat treatment and burn into a pockmarked surface when heated.
The prevention method of steel pipe pitting:
1. Correctly implement the heat treatment system when loading the furnace.
2. Stick to quick turnarounds.
3, pickling can not be too washing, do not owe washing, pickling after timely drawing.
