Slit rolling - Danieli

1 1 Slit rollingV 299 E2 Morg rdshammar Guide Systems, a Division ofMorg rdshammar AB, is a world wide knownproducer of fine guide equipment for hot rollingmills. The company is the original inventor of roll-er guides and has since the beginning been aleading manufacturer of such the last decades there has been a strong dem-and to increase production capacity with a mini-mum on capital rdshammar ventured in the development ofupdated equipment for the multi slitting processsince the late eighties. This process is today world-wide known as the slit rolling technology. Thistechnology as applied to bar mills enables theproduction of two or more bars from one slit rolling technology is a combination of spe-cial roll pass design with designated guideGuiding is our businessequipment to shape and longitudinally separatethe incoming billet into two or more individualstrands which will then be further rolled into finish-ed sizes.

2 In principle the billet will be rolled in thesame way as in conventional rolling up to theintermediate rolling mill. Here, after an acceptablesection is produced, the slitting operation will deciding to implement the slit rollingmethod to an existing rolling mill it is essential toexamine the suitability of this mill for the slit roll-ing and speed requirements have to be carefullycalculated especially with four strand attention has to be paid to the cooling bed,cold shear and bar collecting equipment whenapplying multi strand slitting in order to ensurethe necessary capacity and a smooth O R G R D S H A M M A R3 The slitting technology as applied to continuousbar mills enables the production of two or morestrands from one billet. Depending on plantconfiguration the slitting process can be adaptedto rolling mills with a minimum of four final standsin continuous installation.

3 The process gives thefollowing profits:*Substantial increase in production rates*Reduction in the number of rolling stands*Reduction in operation costsThe slit rolling process differs from conventionalcontinuous rolling by the use of special roll pas-ses and guides to prepare, shape and longitudinallyseparate the incoming billet into two or moreindividual strands for further rolling into thefinished size. In principal this process is achievedas follows:*Reducing the billet conventionally through theroughing and intermediate rolling mill to producean acceptable section for the first special shapingpass at the forming stand.*Precise guidance of this stock to the formingstand where it is reduced and shaped to form asymmetrical forming section .*Further close guidance and control of the dogbone through the separating stand, were thestock is reduced and shaped into a slit pass ,designed to be easily separated into two equalsections of false round.

4 *A special guide on the delivery side of theseparating stand ensures a clean slitting of thebar and now delivers multiple strand of equalsections to their respective finishing the effective continuous operating of the slitrolling process it is important that all mill equipmentis in good order. Particular care and attention mustbe directed to the condition of the rolling mill. Formultiple strand rolling the power availability ofthe finishing train is of great importance and needto be sufficiently ProcessGuidingThe guiding of the leader section to the formingpass and on to the separating pass in the separatingstand is critical in order to guarantee equallybalanced strands. Desired guiding features are listedas follows:*Sound and robust guides*Secure and rigid restbars*Precise guide equipment*Positive, adjustable and secure alignment*Guiding of bar close to the stand*Correctly set up and maintained guides inabsolutely good conditionsBesides this a good control throughout the finishingmill is DesignThe leader sections for the multiple slit rolling pro-cess, square, rectangular or round have to beof very close requires.

5 *Correct pass profile in the rolls*Correct roll gap to ensure no overfill*Correct pass alignment between top andbottom rolls*Sound roll neck bearings and positive rolllocation to avoid axial flow*Stiff rolling mill stands providing rigidscrewdown and roll balance*Sound roll quality and good pass conditions*Uniform stock temperatureProcess Control4It is most important for the entry guides at theforming and separating passes to provide precisebar guidance to ensure equal stock rdshammar Guide Systems provide allspecific guides for the slit rolling process whichoffer all the required facilities and life at the forming stand where starting witha square section it is most important to preciselyalign and laterally hold the leader stock enteringthe forming pass. Here it is essential to produce acompletely symmetrical shaped guide type CTD-01-RS for 2-strand slittingGuide equipment for the slit rolling processWhen slitting into 3-, 4- or 5-strands the entrysection will be a rectangular.

6 If no vertical stand isavailable for edging, it may be needed to use aworking edging guide in the delivery side, in ord-er to produce a section with a close width tolerancewhich is important for the following shaping the separating stand the forming pass must beprecisely aligned and laterally held into theseparating pass. The guide must have a fineadjustment possibility for lateral rdshammar has developed entry roller guidesof 1000-series especially for the slit entry guide type DR4BP of 1000-series incombination with a static delivery guideFour-roller entry guide type DR4BP of 1000-series incombination with working edging guide type WEGFour-roller entry guide type DR4BP of 1000-series incombination with 4- or 5-strand slit guide type MSL45 Basically all guides can be cassette mounted forquick guide change if this is necessary. The passline is kept at all times and the new preset guidetakes up its correct position on the pass roller guides are wider than standard guidesand the roller bearing assemblies are fitted withSKF tapered roller bearings for heavy-dutyapplications.

7 The two rollers next to the rolls, areextra low which admits the guide to be mountedas close as possible to the 2-, 3-, 4- or 5-strand slitting, the width of theguides will be adapted to the size of the O R G R D S H A M M A R5 The rolling sequence in the finishing millThe slit section is a false round, which is guidedinto the oval stand by static entry guides. Theoval produced has to be twisted 90 and entersthe finishing stand through roller guides. In mostcases roller guides with a single pair of rollerswill be used in finishing stands. For the bestutilisation of the roll barrel it is of great importanceto keep the strands as narrow as possible. Thiscan be easily achieved with Morg rdshammarroller guides, in both sections, the entry and the present page we show cassettes for four-strand rolling . Cassettes for other strand distancesare available.

8 For further detailed informationplease contact our nearest equipment for theslit rolling process in the finishing trainAfter the slitting operation the stock continues roll-ing with multiple strands. All guide equipment,either entry or exit guides are mounted in multiplestrand cassettes. Such cassettes can be made for 2,3-, 4- and 5-strand allow rapid guide changes for correctlypre-set guides. The pass line is kept and the newguide will take up its correct the positioning of the roller entry guides inthe finishing stand we recommend laterallyadjustable cassettes to guarantee a correct posi-tion of the oval into the stand with roller guide type SR1 in adjustable four-strand cassetteExit twist guides RTC-1-RS in adjustable four-strand cassette6 Pass sequence andguide schedule for slit rolling3 STRAND2 STRANDM O R G R D S H A M M A RFinished roundSquareor roundExit twist guide Static delivery guideDR2B/1 or DR2 BPStatic delivery guide/Working edging guideDR2B/1 or DR2 BPStatic delivery guideDR2B/1 or DR2 BPSlit guideCTD-01-RS or MSL232 x static entry guide2 x exit twist guide2 x roller entry guide SR12 x static delivery guideStartingsectionFlat passForming passSeparatingpass(False round)

9 OvalSquareor roundExit twist guide Static delivery guideDR2C/1 or DR4 BPStatic delivery guide/Working edging guideDR2C/1 or DR4 BPStatic delivery guideDR2C/1 or DR4 BPSlit guideCTD-02-RS or MSL233 x static entry guide3 x exit twist guide3 x roller entry guide SR13 x static delivery guide72-strand slittingSections 1 and 2 are divided and deliveredto the finish rolling mill as two separate slittingSections1, 2 and 3 are divided and deliveredto the finish rolling mill as three separate into 2- and 3-strandsThe separating techniqueThe separating pass consists of two or more majorsections, which are held together by small stripsof material. During the slitting or separating pro-cess these sections are divided into separate barsof false the slitting operation the divided bars willhave a little fin or fins of material either on theleft, right or on both sides of the slit round the transformation of the slit round stockinto an oval, these fins will be elongated.

10 The rolledin fin on the final product has a depth that isaccepted by the technique is that the separating wheels applydiagonal forces to the slitting section, resulting intolateral forces splitting or dividing the small stripsof material between the upstreams on the finishing train of a 4-slit processM O R G R D S H A M M A R9 From above in actionArrangement of MSL45 with flip opening conveying through to looper10 Pass sequence andguide schedule for slit rolling5 STRAND4 STRANDM O R G R D S H A M M A RFinished roundStartingsectionFlat passForming passSeparatingpass(False round)OvalSquareor roundExit twist guide Static delivery guideDR2D/1 or DR4 BPStatic delivery guide/Working edging guideDR2D/1 or DR4 BPStatic delivery guideDR2D/1 or DR4 BPSlit guideMSL4 or MSL454 x static entry guide4 x exit twist guide4 x roller entry guide SR14 x static delivery guideDR2D/1 or DR4 BPStatic delivery guide/Working edging guideSR 4 Static delivery guideFlat passEdging pass(if available)Squareor roundExit twist guide Static delivery guideDR2D/1 or DR4 BPStatic delivery guide/Working edging guideDR2D/1 or DR4 BPStatic delivery guideDR2D/1 or DR4 BPSlit guideMSL455 x static entry guide5 x exit twist guide5 x roller entry guide SR15 x static delivery guideDR2D/1 or DR4 BPStatic delivery guide/Working edging guideSR 4 Static delivery guide11 For more than 3-strand slitting a multiple strandseparating guide, type MSL, is used.