What is the reason for the pores on the surface and inside of titanium screws?

Release time：2024-07-05 13:35:02 丨 Number of visits：

Titanium screws have a steel like appearance with a silver white luster and are a transition metal. Pure titanium screws have high strength, low density, high hardness, high melting point, and strong corrosion resistance.

Due to the low density of titanium screws, the inertia of titanium liquid during flow is small, and the flow performance is poor. During the production process, it is easy to cause defects such as pores on the surface and inside of titanium screws. To make titanium screws bright and colorful, it is necessary to remove the surface reaction layer of the titanium screws. There are two ways to remove the reaction layer on the surface of titanium screws:

1. Sandblasting: Sandblasting is used to impact the surface of titanium screws with sand particles, generating intense sparks. The temperature rises and reacts with the surface of titanium screws, forming secondary pollution and affecting surface quality. The time is 15-30 seconds, and only the sticky sand, surface sintered layer, and some oxidation layer on the surface of the casting can be removed. The remaining surface reaction layer structures should be quickly removed by chemical acid washing.

2. Pickling: The method of cleaning and pickling can quickly and effectively remove the surface reaction layer of titanium screws, without producing contamination from other metal elements.

Grinding and polishing

1. Titanium screws have high chemical reactivity, low thermal conductivity, high viscosity, low mechanical grinding ratio, and are prone to react with abrasive tools. Ordinary abrasives are not suitable for grinding and polishing titanium screws, and it is best to use superhard abrasives with good thermal conductivity, such as diamond and cubic boron nitride,

2. Chemical polishing: Chemical polishing is achieved by the oxidation-reduction reaction of metals in a chemical medium to achieve the purpose of leveling and polishing. Its advantage is that chemical polishing is independent of the hardness, polishing area, and structural shape of the metal. All parts in contact with the polishing solution are polished without the need for special and complex equipment. It is easy to operate and is more suitable for polishing precision titanium screws with complex structures. However, chemical polishing is difficult to control in terms of process parameters, and it is required to have a good polishing effect on titanium screws without affecting their precision.