Comprehensive Analysis Of Titanium Plate Surface Conditions

The surface condition of  titanium plates  is one of the core factors determining their service performance, service life and adaptability. Titanium plates with different surface conditions exhibit significant differences in microtopography, chemical composition and mechanical properties, which in turn affect their application effects in different scenarios.

 

I. Core Classification and Characteristics of Titanium Plate Surface Conditions

(I) Basic Processed Surface Conditions

1. Hot-Rolled Surface

Hot-rolled titanium plates feature a basic surface formed by high-temperature rolling, which is rough and uneven with rolling textures, showing a light gray/dark gray oxidized color. The surface may have a small amount of oxide scale, debris, as well as slight scratches and indentations without serious defects; the microstructure is uneven with coarse grains and low surface energy.

 

It is mostly used for structural components and non-load-bearing parts with low surface requirements, or as a blank for subsequent pickling and sandblasting. It has the advantages of low cost and high efficiency, with a relatively large thickness deviation, and is suitable for mass production of thick plates with a thickness of more than 4.75mm.

 

2. Cold-Rolled Surface

Cold-rolled titanium plates are formed by rolling at room temperature, with surface quality far superior to hot-rolled plates.

The surface is flat and smooth with delicate textures and no obvious oxide scale, featuring low roughness (Ra≤0.8μm), high dimensional accuracy and small thickness deviation, making it suitable for precision machining. The microstructure has finer grains and high surface energy, ensuring uniform polishing and anodizing effects.

 

3. Annealed Surface

Annealed titanium plates are in M state and undergo annealing treatment after hot and cold rolling, which can eliminate internal stress and refine grains.

 

The surface is uniformly silvery white or light gray without obvious rolling textures, with roughness and flatness between hot-rolled and cold-rolled plates, low internal stress, stable performance and reduced surface defects. It balances processability and surface quality, also serving as a blank for surface modification and deep processing.

 

(II) Surface-Treated Conditions

1. Pickled Surface

Pickled titanium plate surfaces are treated with a mixed solution of nitric acid and hydrofluoric acid, presenting a uniform silvery white color without oxide scale and impurities, smooth and non-glossy with moderate roughness.

 

The microstructure has slight corrosion marks and forms a uniform TiO₂ passivation film. This process can remove oxide layers and oil stains, form a dense passivation film and improve corrosion resistance.It is also an ideal substrate for subsequent treatments such as anodizing and spraying.

 

2. Sandblasted Surface

Sandblasted titanium plate surfaces are a new type of frosted surface formed by spraying abrasives with high-pressure airflow.

The surface is uniformly matte and rough with a roughness of Ra=1.6~6.3μm, no obvious textures, high surface energy and large friction, which is conducive to coating adhesion. It can remove oxide layers and impurities, refine grains, and improve hardness and wear resistance.

 

3. Polished Surface

Polished titanium plate surfaces are divided into ordinary polishing and mirror polishing: the ordinary polished surface is silvery white and bright with Ra=0.1~0.4μm; the mirror polished surface can achieve a mirror effect with Ra≤0.1μm, featuring an extremely flat surface and high surface energy. Polishing can improve finish, aesthetics, corrosion resistance and wear resistance.

 

4. Anodized Surface

Anodizing is a treatment process that forms a dense TiO₂ oxide film on titanium plates through electrolysis in an electrolyte, which can significantly improve corrosion resistance and functionality.

 

The oxide film is uniform with adjustable colors, smooth and wear-resistant, and has both insulating and decorative properties. Titanium substrates with fine and uniform grains can form a more uniform oxide film with stronger resistance to chloride ion corrosion; step-by-step anodizing can further improve the film quality.

 

5. Passivated Surface

Passivated titanium plate surfaces are treated with chromate and phosphate passivation to form a dense passivation film mainly composed of TiO₂ and chromate.

 

The surface is silvery white or light gray, smooth and uniform, with greatly improved resistance to pitting corrosion and crevice corrosion. Its film layer is more dense and stable than that of pickled surfaces, and can block corrosive media such as chloride ions and hydrogen ions.

 

6. Coated Surface

Coated titanium plate surfaces are prepared by forming metal or non-metal functional coatings on titanium plates through thermal spraying technologies such as plasma and flame spraying.

 

The coating is uniform and firmly bonded, and its properties such as high temperature resistance, wear resistance, corrosion resistance, anti-adhesion, electrical and thermal conductivity can be customized.

 

Ceramic coatings with high temperature and wear resistance are used in aerospace; polytetrafluoroethylene coatings with anti-adhesion and corrosion resistance are used in chemical industry; metal coatings with improved electrical and thermal conductivity are used in electronics and electrical engineering. It has strong adaptability and can flexibly meet the needs of various special working conditions.

 

 

Ruihang mainly produces the titanium raw materials. Get more details at: Sam.Rui@bjrh-titanium.com