Surface reaction layer is the main factors influencing the physical and chemical properties of titanium castings, in front of the grinding and polishing of titanium castings, must achieve completely remove surface contamination layer, to achieve a satisfactory polishing effect. Through pickling after sand blasting method can completely remove the surface reaction layer of titanium.

1. Sand: titanium castings sandblasting processing generally choose white corundum rough, sand blasting pressure less than the precious metals, general control below 0.45 Mpa. Because, the injection pressure is too large, sand produce intense impact on titanium surface spark, temperature can react with titanium surface, the formation of secondary pollution, affect the surface quality. Time for 15 to 30 seconds, just remove the casting surface adhering sand, and part and oxide layer on the surface. The rest of the surface reaction layer structure should adopt the method of chemical pickling quick removal.

2. Pickling, pickling can completely remove the surface reaction layer, quickly won't produce other elements and surface pollution. HF - department of HCl and HF - department of HNO3 titanium acid lotion can be used in pickling, but HF - department of HCl acid liquid hydrogen absorption quantity is larger, and HF - department of HNO3 acid liquid hydrogen absorption quantity is small, can control the concentration of the HNO3 to reduce hydrogen absorption, and can be carried out on the surface brightness processing, general HF concentration was 3% ~ 5%, the concentration of the HNO3 was 15% ~ 30% advisable.