Titanium plate and titanium rod surface reaction layer are the main factors affecting the physical and chemical properties of titanium work parts, before processing, it is necessary to achieve the complete removal of surface pollution layer and defect layer. Physical mechanical polishing of titanium plate and titanium rod surface polishing process:
1, blasting:
The blasting treatment of titanium wire castings is generally better with white and rigid jade spray, and the pressure of blasting is smaller than that of non-precious metals, and is generally controlled below 0.45MPa. Because, when the injection pressure is too high, the sand particles impact the titanium surface to produce a fierce spark, the temperature rise can react with the titanium surface, forming secondary pollution, affecting the surface quality. The time is 15-30 seconds and only the viscous sand on the casting surface is removed, the surface sintering layer and the partial oxidation layer can be removed. The rest of the surface reaction layer structure should be quickly removed by chemical pick-up method.
2, pickly washed:
Acid washing removes the surface reaction layer quickly and completely without contaminating the surface with other elements. HF-HCL system and HF-HNO3 acid wash can be used for titanium acid wash, but HF-HCL acid wash absorbs hydrogen, while HF-HNO3 acid wash absorbs hydrogen, can control the concentration of HNO3 to reduce hydrogen absorption, and can lighten the surface, the general concentration of HF in about 3%-5%, HNO3 concentration of about 15%-30%.
The surface reaction layer of titanium plate and titanium rod can completely remove the surface reaction layer of titanium by the method of acid washing after blasting.
Titanium plate and titanium rod surface reaction layer in addition to physical mechanical polishing, there are two kinds, respectively: 1. chemical polishing, 2. electrolyte polishing.
1, chemical polishing:
When chemical polishing, the purpose of flat polishing is achieved by the redox reaction of metal in the chemical medium. Its advantages are chemical polishing and metal hardness, polishing area and structural shape, where the contact with the polishing liquid are polished, do not need special complex equipment, easy to operate, more suitable for complex structure titanium protrusion bracket polishing. However, the process parameters of chemical polishing are difficult to control, which requires that the righteous teeth can have a good polishing effect without affecting the accuracy of the teeth. A better titanium chemical polishing solution is HF and HNO3 according to a certain proportion of preparation, HF is a reducing agent, can dissolve titanium, play a leveling effect, concentration of 10%, HNO3 oxidation effect, to prevent excessive dissolution of titanium and hydrogen absorption, at the same time can produce a bright effect. Titanium polishing liquid requires high concentration, low temperature, short polishing time (1 to 2min).
2, electrolyte polishing:
Also known as electrochemical polishing or anode dissolved polishing, due to the low conductivity of titanium alloy tube, oxidation performance is very strong, the use of hydro-acid electrolytes such as HF-H3PO4, HF-H2SO4 electrolytes on titanium can hardly polish, after the application of external voltage, titanium anode immediately oxidation, and the anode dissolving can not be carried out. However, the use of waterless chloride electrolyte at low voltage, titanium has a good polishing effect, small test pieces can get mirror polishing, but for complex repair can not achieve the purpose of full polishing, perhaps by changing the cathode shape and additional cathode method can solve this problem, still need to be further studied.
