How to deal with the surface defect reaction layer of titanium plate and titanium rod

The surface reaction layer of titanium plate and titanium rod is the main factor affecting the physical and chemical properties of titanium workpiece, and the contaminated layer and defective layer must be completely removed before processing. Physical and mechanical polishing of titanium plate and titanium rod surface polishing process:

1, Sand blasting:
White corundum is generally used for sandblasting treatment of titanium wire castings. The pressure of sandblasting is smaller than that of non-precious metals, and it is generally controlled below 0.45mpa. Because, when the injection pressure is too large, the sand impact on the surface of titanium sparks, temperature rise can react with the surface of titanium, the formation of secondary pollution, affect the surface quality. The time is 15-30 seconds to remove only the sticky sand on the surface of the casting, the sintered layer on the surface and part of the oxide layer. The rest of the surface reaction layer should be quickly removed by chemical pickling.

2, Pickling:
Pickling can quickly and completely remove the surface reaction layer without contaminating the surface with other elements. Hf-hcl series and HF-HNO3 series acid washing solution can be used for titanium pickling, but HF-HCl series acid washing solution has a large amount of hydrogen absorption, while HF-HNO3 series acid washing solution has a small amount of hydrogen absorption, which can control the concentration of HNO3 to reduce hydrogen absorption, and can carry out bright treatment on the surface. Generally, the concentration of HF is about 3%-5%. The appropriate concentration of HNO3 is about 15%-30%.