Causes and control of surface defects of cold rolled titanium plate

Titanium and titanium alloys are very important lightweight structural materials, which have been widely used in aerospace, vehicle engineering, biomedical and other fields. With the development of economy and technology, there are more and more applications of titanium plate, but the surface quality problem is more prominent.

There are two kinds of surface defects of titanium plate: conventional defects and non conventional defects.
Conventional defect:

1. Scratch
Reason: Guide plate, roller, tools and roll is not smooth, there is a stick or a sharp edges and so on, rolling scratch surface. The operation is not careful, so that they collide with each other to form scratch surface.
Measures: Check the tools, the guide plate, the roller and the roll before rolling. Careful operation, do not mess up.
2. Metal indentation
Reason: Rolling edge burr and tail dregs are pressed into the surface of the product.
Measures: Timely eliminate the slab edge burr. Cut off the crack edge, crack head in time.
3. Non-metallic indentation
Reason: Environmental sanitation is poor, the dust falls on the surface of the workpiece. the pickling is not clean.
Measures: Do a good job of health, timely removal of surface adhesion.
4. Pit
Reason: When pressing and annealing, the surface of the pressing plate or the backing plate is covered with dust.
Measures: Clean the surface of pressure plate before entering the furnace.
5. Roll mark
Reason: The roll surface wear, there are pits, spongy surface, and scratches.
Measures: Roll marks are found to be worn or replaced.

Unconventional defects:

1. Surface cracking
Reason: the material is unqualified, the surface crack is not clear or the suction layer is not cleared, in addition, the pressure is not reasonable, the processing rate is small, or the distribution of the secondary processing rate is not equal.
Measures: Strictly control the surface quality of the incoming material, reasonably distribute the processing rate, ensure the uniform annealing temperature and enhance the lubrication.
2. Acid spot
Reason: on the one hand, when pickling, the residual acid is not washed cleanly, and on the other hand, when the plate is annealed in the stack, the surface oxidation is uneven and the degree of surface corrosion is inconsistent after pickling.
Measures: Pickling must be clean, to ensure that the surface of the titanium plate without residual acid. To reduce the thickness of the stack, to ensure that the plate annealed evenly, you can also use sanding treatment.