At high temperature, titanium rods are easy to dry and react with O, H, N and other elements in the air as well as Si, Al, Ma and other elements embedded in the material, forming a surface pollution layer on the surface of the casting, which worsens its excellent physical and chemical properties and increases its hardness. Plasticity and elasticity decrease, brittleness increases.

First, the density of titanium rod is small, so the inertia of titanium liquid flow is small, the fluidity of molten titanium is poor, resulting in low casting rate. The temperature difference between the casting temperature and the mold (300℃) is large, the cooling speed is fast, and the casting is carried out in a protective atmosphere. Porosity and other defects are unavoidable on the surface and inside of cast iron, which have great influence on the quality of castings. Therefore, the surface treatment of cast iron is more important than other alloys.

Two, pickling: pickling can quickly and completely remove the surface reaction layer, the surface will not be polluted by other elements. To unload the inner hole of the outer spoon and retain the inner contraction; Hot isostatic pressing can be used, but the accuracy of its meaning will produce a guiding sound. X-ray detection, surface grinding to remove exposed air bonding, and laser repair of defects were used.

Three, research set and light

1. Mechanical polishing: titanium rod alloy has high chemical reactivity, low conductivity, high viscosity, low machinability, easy drying and reaction, so it is not suitable for dry beverage research and polishing. Using superhard friction materials with good thermal conductivity, such as diamond, cubic boron nitride, etc., the polishing linear speed is generally 900~1800m/min. This is appropriate, otherwise the surface of the titanium rod is prone to grinding and micro-cracking.

2. Ultrasonic grinding: through the action of ultrasonic vibration, the abrasive particles between the grinding head and the surface to be ground move relative to the surface to be ground. Achieve the purpose of grinding and polishing. The advantages are easy to grind grooves and narrow parts that conventional rotary tools cannot grind, but the grinding effect of large castings is not satisfactory.

3. Electromechanical composite grinding; Using a conductive grinding tool, an electrolyte and a voltage are applied between the grinding tool and the grinding surface to reduce surface roughness and improve surface gloss in a combination of mechanical and electrochemical polishing. The electrolyte is 0.9NaCl at a speed of 5V and 3000rom/min. This method can only grind the surface.