NEW. Nozzles for hydromechanical descaling

Transcription

1 NEW Nozzles for hydromechanical descaling SCALE MASTER S U P E R I O R

2 SCALE MASTER S U P E R I O R TThe most exacting demands placed on the surface quality of rolled material combined with a further reduction in the amount of energy used can only be met by using stateoftheart descaling nozzles. SCALEMASTER SUPERIOR Boasting the following advantages: Maximum impact increase compared with previous models, thanks to the elimination of most of the inner turbulences and pressure losses Very even impact distribution across the spray width Stable spray angle over all pressure ranges Compatible with earlier models due to identical flow rate and spray angle graduations Interchangeable with earlier models with regard to dimensions and assembly Longer service life and operational reliability thanks to the use of new materials and a reduction in the number of components. F E AT U R E 3 A coreless stabilizer inside the filter stabilizer unit eliminates pressure losses and turbulences. F E AT U R E 2 A nozzle insert made of special corrosionresistant and temperature shockresistant tungsten carbide, newly developed using CFD. The orifice behind is optimally protected. F E AT U R E 1 A very short, twocomponent nozzle tip made of heatresistant tempered stainless steel. The carbide tip and housing cannot be detached, and are hermetically connected to each other. F E AT U R E A onepart stabilizerfilter unit made completely of stainless steel and newly developed with CFD. 2

3 E X T R A H I G H P E R F O R M A N C E D E S C A L I N G N O Z Z L E S F E AT U R E 4 Extremely pressurestable filters with filter slit geometries optimised by CFD eliminate pressure losses and turbulences. The demands placed on the surface quality of hotrolled sheets and strips are constantly increasing. This is in addition to the increased use of thin hotrolled strips, for example in the production of construction and agricultural machines, and the greatly increased need for heavy plate for the production of oil and gas pipelines. Streakfree and optimally descaled surfaces are required in both cases. The use of surface inspection systems has also led to efforts aimed at optimising hydro mechanical descaling in hot rolling mills. Rising energy costs and ecological considerations are forcing rolling mill operators to define energysaving measures and to implement them in the form of concrete measures. Wherever liquid and gas flow technology plays a role, it is no longer possible to manage without Computational Fluid Dynamics (CFD). At Lechler too, this modern tool is used successfully in conjunction with 3DCAD technology in order to develop new nozzle geometries. This has enabled us to largely eliminate the turbulent flows inside the SCALEMASTER Superior. This shows the comparison with the earlier model very clearly. A further significant reduction of the spray depth, and hence an increase of the impact was the result. Impact increase Nozzle tip 2component nozzle tip without horizontal slit made of heatresistant and tempered steel. The tungsten carbide insert and housing cannot be detached, and are hermetically connected to each other. Increased operational reliability even in the event of water hammers and low spray heights Sealfree connection to the carbide insert prevents internal leakage Nozzle insert A newly developed nozzle insert made of special corrosionresistant and temperature shockresistant tungsten car bide. The discharge orifice behind is optimally protected. Reduction of the spray depth to increase the impact Increased operational reliability even at low spray heights and under high temperature stress High precision guarantees optimum descaling results and surface qualities Evolution of the Lechler descaling nozzles Spray director filter unit A onepart stabilizer filter unit made completely of stainless steel and newly developed with CFD. Allows maximum impact increases Very easy handling in maintenance, and greater operational reliability thanks to a onepart design Greater operational reliability even in the event of water hammers, thanks to a very rigid stainless steel filter section Interchangeability The SCALEMASTER Superior and MiniSCALEMASTER Superior series have identical external dimensions and identical flow rate and spray angle graduations to all earlier SCALEMASTER models. SCALEMASTER Superior and MiniSCALEMASTER Superior can be fitted in existing spray headers without any modifications Simple and economical optimisation of existing descaling systems before (SCALEMASTER HP) Stabilizer filter unit optimised with Compu tational Fluid Dynamics (CFD) after (SCALEMASTER Superior ) 3

4 S C A L E M A S T E R S U P E R I O R LECHLER supplies the SCALEMASTERS series in two different product lines: The "large" nozzle system SCALEMASTERS, Series and the "small" nozzle system MiniSCALEMASTER S, Series Both series are available with the same flow rates and spray angle graduations. The "large" nozzle system Series is recommended for use wherever space permits. With the standard union nut (Part No ), the shortest horizontal nozzle distance [ E ] is 63 mm. Lechler has developed a special nut with a hexagon socket for nozzle distances of between 0 mm and less than 63 mm (Part No ) that allows the weld nipples to move close together. This nut also provides additional protection against external wear. ➀ ➁ L S No. 1 Component Order Weight no. Welding nipple Length: L = 120 mm C Material: L = 100 mm C AISI 304 L = 73 mm C ➂ ➃ 2 Filter stabilizer unit Material: Stainless steel with filter S F =129,3 06S. 46.1Y with filter S F =169,3 06S. 46.1Y ➄ 3 Gasket Material: Copper Nozzle tip.xxx.xx see order table Nut (standard) Material: AISI 431 Max. permissible operating pressure: 600 bar Hex Improved rolled material surface Saves on pump energy Splash water quantity reduced 4

5 Order No. for nozzle tip Type Series Code Spray angle Material code A ø [mm] p = 100 bar (140 psi) [US Gall./min] Water flow rate (V. ) p = 200 bar (2900 psi) [US Gall./min] p = 400 bar (00 psi) [US Gall./min] Flow rate conversion for table.. V 2 = p 2 p 1. * V 1 2)2 p =(V 2. * p [bar] 1 V , Ø 42 1" BSPP , Hex Hex 24 socket Ordering Series + Code + Mat.Code = Order no. example: =.49. A ø = equivalent bore diameter Material code : Stainless steel nozzle tip with tungsten carbide insert Special nut with hexagon socket for very narrow distances between nozzles Order no.: Heavy plate rolling mill

6 M i n i S C A L E M A S T E R S U P E R I O R The "small" nozzle system Mini SCALEMASTER Superior, Series allows very short spray heights [h 2 ] to be realised. Shortening the spray height enables the impact to be increased significantly. At the same time, it is possible to reduce the cooling of the rolled material thanks to a smaller water quantity. This is particularly advantageous for hotrolling thin slabs and heavy plate. Lower spray heights are also advantageous for the construction and configuration of spray rings for descaling profiles, billets and rounds. This nozzle system allows a minimum spray height [h2] of 0 mm to be realised. The Lechler special union nut (Part No ) with a hexagon socket allows nozzle distances of 34 mm minimum. ➀ ➁ L S No Component Order Weight no. Welding nipple Length: L = 32 mm C Material: L = 39 mm C AISI 304 L = 0 mm C Filter stabilizer unit Material: Stainless steel Gasket Material: Copper with filter S F =129,3 06S. 36.1Y with filter SF =169,3 06S. 36.1Y ➂ ➃ ➄ 4 Nozzle tip.xxx.xx see order table Nut (standard) Material: AISI 431 Hex Max. permissible operating pressure: 600 bar Spray height reduction Improved rolled material surface quality Saves on pump energy water flow rate reduced Less cooling of rolled product 6

7 Order no. for nozzle tip Type Series Code Spray angle Material code A ø [mm] p = 100 bar (140 psi) [US Gall./min] Water flow rate (V. ) p = 200 bar (2900 psi) [US Gall./min] p = 400 bar (00 psi) [US Gall./min] ,.92 Flow rate conversion for table.. V 2 = p 2 p 1. * V 1 2)2 p =(V 2. * p [bar] 1 V , ,0 Ø 32 G3/4 3/4" ISO BSPP , Hex SW 22 socket (Innen) Ordering Series + Code + Mat.Code = Order No. example: =.49. A ø = equivalent bore diameter Material code : Stainless steel nozzle tip with tungsten carbide insert Special nut with hexagon socket for very narrow distances between nozzles Order no.: Finishing scale breaker in front of a rolling mill for thin slabs 7

8 N O ZZ LE AR RAN G E M E NT O N TH E S P RAY H EAD E R The following apply to the arrangement on the spray header: E = C D C = cos γ B β =, 10 or 1 A = Spray length B = Spray width C = Spray width in rolling direction D = Overlap E = Nozzle distance h 2 = Vertical spray height α = Nozzle spray angle β = Angle of inclination γ = Offset angle of the nozzle against pipe roll axis Spray length (A), Spray width (B, C), Overlap (D), Nozzle distance (E) at vertical spray height (h 2 ), Nozzle spray angle (α) and Angle of inclination (β) Vertical spraying height h 2 [mm] Angle of inclination β = 1 A [mm] B C D E B C D E B C D E B C D E [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] Nozzle spray angle α at p = 10 bar α = 22 α = 26 α = 30 α = 40 27,0 3, 49, 70,0 79,4,4 96,9 104,9 110,6 11, ) 44. 2) 6, ) 2.7 3) ) ) 4.3 2) ) , ) ) ) Explanation of the table: 1. Spray widths: These values refer to a spray pressure of p = 10 bar. Allowance is made in the table for the spray convergence. Details of spray widths at other spray pressures are available on request. 2. Spray angle tolerances: + 3 at α = 22, 26 and 30, + at α = 40. This means that B + C are minimum values. 1) Only MiniSCALEMASTERS with hexagon socket nut 2) only MiniSCALEMASTER 3) only with hexagon socket nut

9 P L AN N I N G R E LIAB I LIT Y THAN KS TO R E LIAB LE P E R F O R MAN C E DATA Only when all performance data is known in advance can the plant be optimally designed The principle of impact measurement Efficient descaling requires not only precision nozzles but also an optimum nozzle arrangement on the spray header. The nozzle measuring technology represents the basis for both of these requirements. The impact distribution is a significant factor for the configuration and assessment of descaling nozzles. A new computercontrolled measuring device allows a threedimensional depiction of the impact on the surface being sprayed. This enables precise quantitative and qualitative results to be obtained across the entire surface being sprayed. A pressure sensor passes through the spray jet at a defined speed and with defined movement. As it does so, the computer records the pulses in the jet and converts them into a threedimensional impact representation (see below). Only nozzle manufacturers who have at their disposal highly developed measuring technology are also able to fulfil the demands that today's modern rolling mills place with regard to a constantly high product quality in order to guarantee process reliability and applicationrelated consultation competence. 3D measurement protocol, impact measurement 9

10 TH E C O R R E CT N O ZZ LE AR RAN G E M E NT AN D ALI G N M E NT AR E C R U C IAL Nozzle spray positions 1. All nozzle jets turned parallel in one direction (see Fig. 1). 2. Nozzle jets, half of them turned outwards in opposite directions. This directs the spray water to both sides (see Fig. 2). Nipple installation So that the correct alignment of the nozzle mouthpiece (1 offset angle to the header's longitudinal axis see Fig. 1, 2) is guaranteed, the weld nipple on the spray header must be positioned so that its flat inner surfaces are parallel to the header's longitudinal axis. This is best achieved with the alignment aid supplied as an accessory (Fig. 4, Order No and ). To do this, it is inserted into the flat nipple opening. A rule (or similar) can now be used to easily bring the nipple into the correct parallel position where it can be welded in place. (see Fig. 3) Fig. 1 Fig. 2 Order no Alignment tip Order no. Order no. Order no Alignment tip Fig. 3: Installation example for weld nipple Alignment tip The installation aid (Fig. 4, Order No and ) is also used as a dummy part to shut off nozzle connections or in pressure tests performed on the spray pipe. Removal aid Protected tip The nozzle tip is positioned set back in the nut in such a way that it is protected against mechanical damage. The required 1 spray offset is already incorporated in each nozzle mouthpiece. This eliminates the possibility of incorrect installation. It also means that the correct position of the nozzle mouthpieces is guaranteed when the nozzle is changed. General instructions for nozzle inspection Nozzles are subject to wear. The condition of the water and the environment can both affect nozzle life. Therefore, a regular nozzle inspection program should be established to ensure proper performance of the nozzle at all times. The intervals for such a program must be established at each installation. Factors such as solid contents in the water can cause wide variations in nozzle wear rates. The removal aid (Fig., Order No. 06S.491.1C and 06S.391.1C for Mini SMS) is pushed onto the recess on the mouthpiece. The entire nozzle unit can be pulled out when the union nut is unscrewed. (see Fig. 3) Fig. 4: Alignment tip / dummy part Fig. : Removal aid (data sheet on request) 10

11 C L E A R O B J E C T I V E S, P E R F E C T R E A L I S A T I O N SystemAudits Most cases involving the decision to modernise a descaling plant also involve a combination of various requirements. It is therefore important for the aims to be clearly defined. This gives the plant operator a clear perspective for being able to plan the implementation of the optimisation measures with the aid of the audit report. An audit of a descaling system is a systematic and structured procedure for defining how the existing nozzles and spray header arrangement, the operating and maintenance practices and the process data affect the surface quality. An audit typically includes the following: Recording and evaluating the operating and performance parameters in order to determine the exact state of the descaling plant. Cause determination for special operating and plant problems. A proposed implementation plan for realising the targets being aimed for, including the measures required for this. Recommendations for improving the plant, processes, operation and maintenance. Fig. 1: Heavy plate with scale streaks Lechler DESCALE With the introduction of the SCALEMASTER descaling nozzles in 1992, Lechler was the first nozzle manufacturer to develop and successfully use a configuration program. Since then, most descaling systems of the largest and most renowned plant builders have been designed and constructed with Lechler DESCALE software. Hundreds of descaling spray headers throughout the world have been optimised in this way. In many cases, Lechler has also made a crucial contribution here towards increasing surface quality and plant efficiency. Fig. 2: Simulation and analysis with Lechler Descale»before«Spray jets with insufficient overlap. Fig. 3: Optimisation with Lechler DESCALE and correct overlapping»after«spray ring For rounds, the Scalemaster descaling nozzles can also be arranged in a circular configuration. Spray header If required, LECHLER can also supply complete descaling spray headers. Plant modernisation aims There are various reasons for performing a detailed descaling audit. The most common of these are: Recognising and avoiding surface defects Improving product quality Improving the descaling effect with increased spray impact Improving ease of maintenance and lowering maintenance costs Reducing the water flow rate and the temperature loss on the rolled material Changing the product dimensions and steel grades (product mix). 11

12 Questionnaire for Nozzle Arrangement Lechler GmbH Precision Nozzles Nozzle Systems P.O. Box Metzingen / Germany Phone: +49 (0) Fax: +49 (0) info@lechler.de Internet: E E E Company Responsable Address h 2 β α Phone γ Fax Pass line Strip width Questionnaire about existing Descaling Nozzle Arrangement Name Date Department Location of descaling installation: Behind the furnace RSB FSB Interstand descaling Format Dimensions [mm] Nozzle Data Strip top bottom Slab Number of headers Plate Nozzle type Bloom Horizontal distance (E) mm mm Billet Vertical spray height (h 2 ) mm mm Rounds Spray angle (α) Material speed m/s Offset angle (γ) Pressure at header bar Impignement angle (β) Available max. l/min water flow l/h Room for sketch: Belgium: Lechler S.A./N.V. Avenue Mercatorlaan, Wavre Phone: (10) Fax: (10) info@lechler.be China: Lechler Intl. Trad. Co. Ltd. Beijing Rm. 1202A Diyang Tower No. H2 Dong San Huan Bei Lu Phone: (6) , Fax: (6) info@lechler.com.cn Finland: Lechler Oy Kalliotie Tuusula Phone: (3) Fax: (3) info@lechler.fi France: Lechler France, S.A. Bât. CAP2 B1 6672, Rue Marceau 93 Montreuil cedex Phone: (1) Fax: (1) info@lechler.fr Great Britain: Lechler Ltd. 1 Fell Street, Newhall Sheffield, S9 2TP Phone: (0114) Fax: (0114) info@lechler.com India: Lechler (India) Pvt. Ltd. Plot B2 Main Road Wagle Industrial Estate Thane (W) Phone: (22) Fax: (22) lechler@lechlerindia.com Sweden: Lechler AB Box Hagfors Phone: (46) Fax: (46) info@lechler.se Spain: Lechler S.A. Avda. Pirineos 7 Oficina B7, Edificio Inbisa I 2700 San Sebastián de los Reyes, Madrid Phone: (34) Fax: (34) info@lechler.es USA: Lechler Inc. 44 Kautz Road St. Charles, IL Phone: (630) Fax: (630) metals@lechlerusa.com Edition 0/0 GB 1000 LEC007 S Subject to technical modification