Hot rolling defects pdf

Abstract during a hot rolling process, surface defects on strips can severely affect the quality of the rolled product, particularly for two conditions. Pdf analysis of the surface defects in a hotrolled lowcarbon c. Variation in the work across the width in sheet rolling occurs because the roll gap is not perfectly parallel a. Blowhole continuous annealing line rolling defects. Migration of slab defects during hot rolling request pdf. Analysis of the surface defects in a hot rolled lowcarbon cmn steel plate article pdf available in journal of failure analysis and prevention 173.

Occurrence of surface defects on strips during hot rolling process by fem. We have seen that the rolling load is dependent on roll diameter, higher the roll dia, higher the. Detectable defect types are many and include shells, cracks, pinholes, scabs, inclusions, laps and overlaps figure 2, as well as repetitive defects figure 3. In order to reduce the roll force, we can reduce roll diameter, or reducing the friction. Similarly, smaller reductions requires lower roll force. Request pdf migration of slab defects during hot rolling blisters and slivers are serious defects that can lead to downgrading and rejection of interstitial free if steels used for. Advanced process and quality control in hot rolling mills. Hot rolling is employed for rolling of steel slabs to hot strips in hot strip mills. As the deflection of rolls occurred by the high forces of rolling, there are two types of rolling defects. Pdf occurrence of surface defects on strips during hot rolling. During hot rolling the microstructure and mechanical properties of the material change with its thermomechanical state, determined by composition, percent reduction, strip thickness, strip speed, and heat transfer. Corrosionpedia explains hot rolling the nonuniform initial grain structure of metal consists of large columnar grains growing in the direction of solidification. Use of automatic surface inspection systems in hot rolling mills and pickling.

Pdf during a hot rolling process, surface defects on strips can severely affect the quality of the rolled product, particularly for two conditions find, read and. Analysis of hot rolling events that lead to ridge buckle defect in steel. Occurrence of surface defects on strips during hot rolling process by. Zerodefectstrategy in the cold rolling industry fachvereinigung. Pdf quality control system for a hotrolled metal surface. Inspectors guide mat problems texas department of highways and public transportation file d10r p. Rolling is one of the most important industrial metal forming operations. Defects in metal forming processes and their remedies. Defects stem from a variety of causes such as poor billet quality, worn rolling mill parts, and process malfunctions. Pdf occurrence of surface defects on strips during hot. Possible source of surface defects for hot or cold rolling strips can be some places in manufacturing process as. One of the problems that might occur during rolling is defect formation leading to. Defects in hot rolled products1 rolling metalworking grinding. A presence of surface defects of steelsmelting and rolling origin is peculiar to the production of hotrolling mill.

Like any other hot rolling operations, rolling of hot strip is also a plastic deformation of the material of the slab caused by compressive force. Blowholes cold rolled uncoated sheet rolling defects. We have seen that the rolling load is dependent on roll diameter, higher the roll dia, higher the roll force. Blowoff structure hot dip galvanizing line rolling defects. Blisters and pinholes hot rolled flat steel products rolling defects. This is usually brittle with weak grain boundaries and may contain defects such as shrinkage cavities, porosity caused by gases, and foreign material such as metallic oxides. On this channel you can get education and knowledge for general issues and topics. On rolling they may result in cracks which may reach a critical value and make the product rejectable. For steels, hot rolling is generally conducted at 8501200 c, in the austenite phase, while for aluminum it is conducted at 350500 c.