This report documents modeling results of pnnls efforts to. Work on surface defect detection of hot strips and barsrods has also. Companion volume to cold rolling of steel by william roberts circa 1978 and number two of the series. Springing when the face of the board remains flat and the edge bends inwards to form a curve. Defect inspection system for steel wire rods produced by hot. If the temperature of the metal is below its recrystallization temperature the process is known as cold rolling process. Rolling is the process of reducing the thickness or changing the cross section of a long workpiece by compressive forces applied through a set of rolls, as shown in figure 51. Occurrence of surface defects on strips during hot rolling process by fem abstract during a hot rolling process, surface defects on strips can severely affect the quality of the rolled product, particularly for two conditions. Results section 5 effects of work r o ll p r o file. On the basis of a previous study defect prediction in hot strip rolling 4, which was done for the same dataset, there was a lot of useful information on the features and their segmentation in proportion to the retentions. Model for mechanical properties of hot rolled steels by ryu, joo hyun department of ferrous technology computational metallurgy graduate institute of ferrous technology pohang university of science and technology a thesis submitted to the faculty of pohang university of science and technology in partial fulfillments of the. The average person may be completely unaware of what rolling is, but it is something that is extremely important to know in the steel industry.
Report on best available techniques bat in the german. Traditional manual surface inspection procedures are awfully inadequate. Defects in metal forming processes and their remedies. Finite element simulation of hot continuous rolling of. Some of the defects are caused by the cambering of the rolls while the rolls being out of parallel can cause others.
Such defects may remain undetected in intermediate processing stages and ultimately show up. Defects in hot rolled products1 rolling metalworking grinding. Online classification of surface defects in hot rolling processes qingyu yang, qiang li and judy jin department of industrial and operations engineering university of michigan ann arbor, michigan tzyyshuh chang og technologies, inc. Sliver defects on low carbon steels, cold rolled strips dumitrescu a. Quality control system for a hot rolled metal surface igor mazur1, toncho koinov2 1 lipetsk state technical university. Dross is signified by zinc streaks on a hot dip strip, and dross pickup can result from contaminants picked up in the zinc. 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.
The hot rolling process california steel industries. Many metals tend to develop edge cracks during hot and cold rolling. Seasoning twisting warping when the ends of the boards are twisted in opposite direction. The study was utilized using the selforganizing maps, originally developed by kohonen 10, which are an unsupervised.
Mahapatra3 the surfaces of continuously cast steel blooms exhibit a variety of surface features and defects, which were investigated to reveal the interactions at the meniscus between the steel shell and. Similarly, smaller reductions requires lower roll force. Review of analysis on forging defects for quality improvement in forging industries mr. Over the life span of a rolling mill the requirements in terms of product quality and the range of steel grades may change significantly. Audits of existing hydro mechanical descaling systems in hot rolling mills as a method to enhance product quality jurgen w. Forging analysis is done to explain that how the defects occur and how to prevent them. This defect happens when you are rolling material that is. An extremely important part of the finishing line is. Classification of welding defects one of the iiw documents classifies all welding defects into six groups according to their appearance. Introduction scale defects are a common group of surface defects in hot steel rolling, and it is therefore important to recognize the risk factors that cause scale on the surface of steel products. In flat rolling the final shape of the product is either. The starting material is usually large pieces of metal, like semifinished casting products, such as slabs, blooms, and billets. Report on best available techniques bat in the german ferrous metals processing industry final draft deutschfranzosisches institut fur umweltforschung dfiu frenchgerman institute for environmental research university of karlsruhe th o.
Leadfree defects in reflow soldering the ipc610d acceptability of electronic assemblies will shortly be available and section 5. The first in the ussr rolls for hot rolling mills were produced from ingots weighing up to 40 tons at uralmashplant in 1934. In order to reduce the roll force, we can reduce roll diameter, or reducing the friction. Acknowledgements thismanualhasbeenpreparedwithinformationandassistance fromthealuminumassociationandmembercompaniesrepresented onthesheetandplatedivision. Rolling defects and remedies pdf these shapes are further processed through hot rolling, forging or extrusion, to. Risk management and financial institutions, 4th edition. There are two types of rolling process flat and profile rolling. Hot rolling scrap reduction through edge cracking and surface defects control improving energy efficiency in hot rolling by increasing recovery rates hot rolling of large ingots is the predominant process for producing plate, sheet, and foil aluminum products.
So some of rolling defects are provided in the metal forming. We have seen that the rolling load is dependent on roll diameter, higher the roll dia, higher the. If modelling hot rolling of steel under industrial conditions, values of 50120 kwm 2 k are more useful. The formation of edge cracks during rolling of metal sheet. Defect surfaces are often examined in a scanning electron microscope sem to aid to determine their root cause. Occurrence of surface defects on strips during hot rolling process by fem. In both cases, the layer of scale is an important parameter. Prediction of under pickling defects on steel strip surface. In hot rolling soft alloys, surface defects occur because rolling plants only scalp the top and bottom ingot surfaces before rolling, not the sides of the ingot. The following are the common defects arising in different types of rolling stocks. Common metal casting defects introducing various metal casting defects with many pictures by dandong foundry in china. Advanced process and quality control in hot rolling mills using eddy current inspection autor. Ann arbor, michigan keywords hot rolling processes, multilevel poisson.
Hot rolling is employed for rolling of steel slabs to hot strips in hot strip mills. Scale defects are a common group of surface defects in hot steel rolling, and it is therefore important to recognize the risk factors that cause scale on the surface of. Hot rolling scrap reduction through edge cracking and. Threedimensional volumetric defects create a lesser notch effect, but can amplify stresses by reducing the load bearing area. Simulations of the hot rolling of u10mo coupons encapsulated in lowcarbon steel have been. The existence of scale during hot rolling between steel and rolling rolls has significant effects on the tribology,14 heat transfer,5 and steel surface properties. Modeling of hot tearing and other defects in casting processes. The stress, strain, temperature and rolling force of the hot continuous rolling process are simulated to analyse the cause of rolling defect, then the roll pass optimization is worked out based on the analysis of the rolling force variation. Unesco eolss sample chapters materials science and engineering vol. The hot metal is passed between two rolls to flatten it, lengthen it, reduce the crosssectional area and obtain a uniform thickness. Apr 29, 2015 rolling metal forming apratim khandelwal. We have seen that the rolling load is dependent on roll diameter, higher the roll dia, higher the roll force. A buckle is a series of waves, usually transverse to rolling direction, varying in severity and frequency. Hot rolling is a metalworking process that occurs above the recrystallization temperature of the material.
Leadfree smt can be challenging however, this challenge can be reduced if the. Pdf occurrence of surface defects on strips during hot. During a hot rolling process, surface defects on strips can severely affect the quality of the rolled product, particularly for two conditions. Investigation of strand surface defects using mould instrumentation and modelling b. The elastic deformation of mill takes place on the metal. Clad steel plates have been utilised with great success in processing vessels, heat exchangers, tanks and a. The simulated results are verified by the actual test.
Sharp flange, thin flange, less radius at the root of the flange, deep flange, hallow tire, thin tire and flat tire. Defects in the final product of mechanically worked metal may have originated. Soldering will include information on acceptable and defective leadfree solder joints. Caused by shrinkage longitudinally along irregular grain. Surface quality assured steel bar program this project is intended to alleviate surface quality problems faced by the u.
In rolling the crystals get elongated in the rolling direction. Caused by shrinkage along spiral or interlocking grain. In hot rolling process slabs are heated in a reheating furnace before being processed. Bent axle, notched axle, grooved axle, scored journal, warm box, hot axle and defective. File bability theory to identify possible causes, and suggests remedies. Rolling metal working introduction the process of deforming a metal plastically as is done in any metal forming process by passing it between rolls roll arrangement is called rolling in simple terms. Slabs are subsequently rolled into hot strips and then to cold strips. Rolling is one of the most important industrial metal forming operations. Thomas, university of illinois uiuc as computational models mature, their practical bene.
These are the common sand casting defects on the surface and inside of cast iron and cast steel parts. Coating defects detection, causes and cures edward d. On the left page, the causes of the defect have been. Underfilled hot rolling defects vcracks heavy plate defects rolling defects vshape hot rolled products rolling defects void formation around a hard inclusion hot rolling defects waviness cold rolling defects wavy head or tail of a plate heavy plate defects rolling defects weld electrolytic galvanizing line rolling defects. Analysis of the surface defects in a hotrolled lowcarbon c. Hot rolling practice an attempted recollection saral dutta. The plant began producing large ingots, weighing 60 tons and more, in 19351936, which allowed to manufacture large backup rolls for rolling mills. The hot rolling process the primary function of the hot strip mill is to reheat semifinished steel slabs of steel nearly to their melting point, then roll them thinner and longer through 12 successive rolling mill stands driven by motors totaling 77,000 hp, and finally coiling up the lengthened steel sheet for transport to the next process. Prediction of under pickling defects on steel strip surface valentina colla, nicola matarese and gianluca nastasi percro, istituto tecip scuola superiore santanna, pisa, italy collan. Review of visionbased steel surface inspection systems. The hot rolling process california steel industries, inc. During steel production, surface defects in the steel formed in the hot rolling process account for 50% of.
Migration of slab defects during hot rolling request pdf. In this handbook all the major defects have been listed with an accurate description and sketch indicating the appearance of the defect and the position in the container where it is most commonly found. Kling, advanced process and quality control in hot rolling mills using eddy current inspection, in cd proceedings of 9th european conference on ndt, ecndt 2006, berlin, germany, we. Multiplestand finishing group detection automatic andor visual inspection of the hot rolled strip surface during hot rolling and pickling defects prevention use of deburring machine. Technical report deformation behavior of oxide scale in hot. Ann arbor, michigan keywords rolling process, feature selection, genetic algorithm, support vector machine svm. The heated slabs from the furnace are rolled to attain its desired dimension through different steps. This paper presents a novel method to study continuously cast slab defects inclusions, pores, gas entrapments in terms of their migration towards the surface during hot rolling. Neale encyclopedia of life support systems eolss serious. Investigation of strand surface defects using mould. Pdf occurrence of surface defects on strips during hot rolling. Occurrence of surface defects on strips during hot rolling.
Modeling of hot tearing and other defects in casting processes brian g. Occurrence of surface defects on strips during hot rolling process by. Therefore i hope this book will be useful in giving a general understanding of especially big components. Defect inspection system for steel wire rods produced by hot rolling process article in international journal of advanced manufacturing technology 70912 february 2014 with 260 reads. A rolling mill is a complex machine having two or more working rollers, supporting rollers, roll stands, drive motor, reducing gear, flywheel, coupling gear etc. Engineering with clad steel the cost saving from using clad steel rather than solid cra is particularly valid when the total thickness increases or when the cladding grade becomes more complex and hence expensive. Thorough account of the hot rolling process and facilities as well as followup treatments given to hot rolled products. Forging rolling defects free download as powerpoint presentation.
Hot rolling has typical recovery rates of 82%, because 18% of the original. Effects of rolling parameters on the shape of cold rolled strip. Defects metal working and rolled products defects in metal working process defects in the final product of mechanically worked metal may have originated from any one or a combination of the following. Defects introduced into metals during fabrication and service. Slivers are loose or torn pieces of steel rolled into the surface. Related of all the defects, and description of practical remedies andsurface wrinkle defect of carbon steel in the hot bar rolling process. Hot and cold rolling explained to those on the outside, the rolling process is an unknown. When hot rolling steel in the laboratory, using relatively small rolling mills, values of 420 kwm 2 k appear to be the correct magnitudes. Rolling defects rolling metalworking civil engineering scribd.
After the grains deform during processing, they recrystallize, which maintains an equiaxed microstructure and prevents the metal from work hardening. Edge cracks need to be removed by a trimming operation, and they may cause rupture of the sheet in the rolling mill. 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. Iii defects introduced into metals during fabrication and service a.
Hot rolling scrap reduction through edge cracking and surface. I am assistant engineer in mechanical maintenance divission. Blowhole and pinhole this is a kind of cavities defect, which is also divided into pinhole and subsurface blowhole. Hot rolled steel is the most common product of the hot rolling process, and is widely used in the metal industry either as an end product or as raw material for subsequent operations. It consist of sheet metal material having thickness less than 200 m. Identification of impacting factors of surface defects in hot rolling processes using multilevel regression analysis nong jin and shiyu zhou department of industrial engineering university of wisconsin madison, wisconsin tzyyshuh chang og technologies, inc. Rollers may be plain or grooved depends upon the shape of rolled product. Model for mechanical properties of hotrolled steels. The ingot used for mw may contain defects pores, microcracks or inclusions which may remain as such or get aggravated during working operation. Review of analysis on forging defects for quality improvement. Defects in hot rolled products1 free download as word doc. Advanced process and quality control in hot rolling mills. Hot rolling occurs above the recrystallization temperature of the material. Parameter settings to reduce strip shape defects and process.
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