The regulations on the surface treatment technology of titanium alloy castings are mainly based on the national standard "Technical Specifications for Surface Treatment of Titanium Alloy Castings" (GB/T 39330-2020). The standard specifies in detail the surface treatment, quality inspection, quality control and technical safety of the surface of titanium and titanium alloy castings. The following are some of the main regulations on the surface treatment technology of titanium alloy castings: I. Surface Treatment Method Sandblasting Purpose: To remove the sand sticking, surface sintering layer and part of the oxide layer on the surface of the casting, to prepare for subsequent treatment such as pickling or electroplating. Requirements: White corundum is generally used for sandblasting treatment. The pressure of sandblasting is controlled below 0.45MPa to avoid the intense sparks caused by the impact of sand particles on the titanium surface, which will cause the temperature to rise and react with the titanium surface, forming secondary pollution. Purpose of pickling: To quickly and completely remove the reaction layer on the surface of the casting, such as oxide layer and other dirt, while avoiding the pollution of other elements on the surface. Requirements: Commonly used pickling solutions include HF-HCl series and HF-HNO3 series. HF-HCl series pickling solution has a large hydrogen absorption, while HF-HNO3 series pickling solution has a small hydrogen absorption and can brighten the surface. During the pickling process, it is necessary to control the concentration of the pickling solution (such as HF concentration at 3% 5%, HNO3 concentration at about 15% 30%) and temperature (generally at 2025 C). The pickling time is about 35 minutes. After pickling, the casting must be cleaned in water and dried in hot air flow. Other methods The surface treatment of titanium alloy castings may also include advanced surface treatment technologies such as electrolytic mechanical composite grinding, barrel grinding, chemical polishing, and electrolytic polishing. These methods can further reduce surface roughness and improve surface gloss, but the operation is relatively complicated and suitable for occasions with extremely high requirements for surface quality. II. Quality Inspection and Control Purpose: To ensure that the quality of titanium alloy castings after surface treatment meets the standard requirements. Requirements: Strict quality inspection of castings after surface treatment should be carried out, including appearance inspection, dimensional accuracy inspection, surface roughness inspection, etc. At the same time, a quality control system should be established to monitor all links in the surface treatment process to ensure the stability and consistency of process parameters. III. Technical safety requirements: During the surface treatment of titanium alloy castings, safety operating procedures should be strictly observed, and necessary protective equipment should be worn, such as protective glasses, protective clothing, gloves, etc. At the same time, the integrity of treatment equipment and tools should be ensured to prevent safety accidents caused by equipment failure or improper operation.