Gestamp HardTech utvecklar i samarbete med Swerea

Samarbete i tuffa tider stärker konkurrenskraften. Tillsammans med Gestamp HardTech har Swerea KIMAB och Swerea MEFOS påbörjat ett 2 årigt projekt på totalt 8,55 miljoner kronor. Projektet handlar om utveckling av tillverkningsprocessen för presshärdade fordonskomponenter i borstål. Resultatet av projektet förväntas leda till en mer miljövänlig och kostnadseffektiv tillverkningsprocess av presshärdade komponenter samt förbättrade egenskaper för dessa.

The roller levelling machine can be used for both cold and hot levelling trials on narrow strips and rolled sections. Complete instrumentation makes it possible to measure speed, force and torque for each roll.

For technical details, see brochure (page 23). 

Our e-mail addresses are written "firstname.surname(at)swerea.se".

Our e-mail addresses are written firstname.surname(at)swerea.se

Our e-mail addresses are written firstname.surname(at)swerea.se.

Our e-mail addresses are written This email address is being protected from spam bots, you need Javascript enabled to view it .

- for work-roll profiles and temperature measurements in hot-strip and plate rolling

Hardware and software for calibration of shape, profile, thermal expansion and wear models, such as the CROWN models used in hot-strip and plate rolling.

Roll-Gap Profiler

In order to calibrate the CROWN models, a device for measuring the unloaded roll gap has been developed. The instrument is called a roll-gap profiler and can be used to measure thermal expansion, wear and surface temperature of the work rolls.

The roll-gap profiler measurement rig consists of two aluminium bars, two contact inductive distance transducers and two thermocouples. A measuring wagon slides along the aluminium bars, ensuring good tracking of the equipment during measurement. The roll-gap profiler is constructed with a movable roll-gap distance-measuring device relative to the wagon, which means that only one contact inductive distance transducer is needed. On the wagon there is also a measuring wheel, which gives the position along the work roll face length, and two thermocouples, which register the surface temperature of the rolls. The roll-gap profiler is pushed with a long handle through the roll gap from one side to the other during a rolling pause. The electronic signals from the measuring devices are transferred via cables inside the handle to the measurement interface. Immediately after measurements have been completed, the interface can be connected to the printer to print the axial position and the roll-gap data. All measurements are stored in the measurement interface, which can be connected to a personal computer for later analysis. The Profile program for the PC can be used to store measured data and to display and print out graphs. The graphs and measured values can be transferred to word processing and calculation programs for incorporation in written reports.

Several Roll-Gap Profilers have been in use at U.S., Japanese and Scandinavian steel and aluminium companies.

Technical description

• One axial position sensor. Accuracy ±2 mm.
• One roll-gap measuring probe (LDT1) covering WR diameters from 650 to 800 mm. Rollgap distance 65 mm. Total accuracy ±3 μm. Measurement is possible even in the presence of water or oil droplets.
• One LDT (LDT2) used for temperature calibration. Readings of LDT2 minus LDT1 change less than ±2 μm when temperature changes from 0 to 100 °C.
• Two thermocouple probes. Max 100 °C. Response speed: 0.4 s (63%), 3.0 s (99%). Accuracy ±1 °C.
• Removable electronic interface.
• Serial printer for hard copy of results.
• Profile PC S/W for processing of measured data, making graphs and printing. • English technical documentation and user guide.

Verification of models

The different CROWN models have been successfully verified in the 4-high mill at MEFOS’s pilot plant and in production 4-high and 6-high plate and strip mills.

The models for predicting plate (strip) temperature, thermal expansion, wear and elastic deformation comprising the CROWN models have been verified through extensive testing at some Scandinavian plate-rolling mills. A set of about 700 plates of different sizes were rolled with newly ground work and backup rolls. About 60 plates spread over the entire set were cut, and micrometer and ultrasonic measurements of the plate transverse profiles were made on each side of the cut. The work roll profiles were measured many times during the campaign with the aid of the ROLL-GAP PROFILER.

The CROWN software and the roll-gap profiler are marketed by MEFOS and can also be used for contract research and consultation within the field of rolling process technology.

MEFOS has developed a fast, reliable and inexpensive straightness meter for bars and tubes. This version of the apparatus, which is patent pending, is made for rounds of 90-mm diameter. Other models are equipped for measurements of varying dimensions. The apparatus is manually operated.

The apparatus has a built-in electronic device for data acquisition and data processing. The device can store measurements from several bars and tubes.

The raw data from the BT straightness meter can be transferred to a PC by a serial line. The communication is handled by the included software package. Programs for evaluation and plotting of the measurement results are included.

It is also possible to detach the electronic device from the apparatus and connect it to a PC. All the data can be transferred to the PC and the evaluation can be performed directly on the screen by the software package.

The BT straightness meter is equipped with special differential transformers measuring the bar curvature in two directions. Properly calibrated, the maximum error is a curvature of 16 ¦Ìm per meter bar length. If the error is systematic this gives a straightness accuracy of 2.5 mm over a bar length of 10 m. This is far more precise than any known customer demands for this group of products today. The apparatus measures straightness deviations in all directions as well as spiral twist of the bar/tube.

Technical specification

Figure 1 - Positions of the rolls in a 20-high rolling mill.

1. Work roll
2. 1st intermediate roll
3. Inner 2nd intermediate roll
4. Outer 2nd intermediate roll
5. Inner backup roll
6. Outer backup roll

Cluster lets you set values for all the rolls, considering:

• Diameter (mm)
• Young's modulus (GPa)
• Roll profiles, strip profile (mm)
• Distance between the centre of the mill and the centre of each roll (mm)

One feature of this rolling mill design (see Figure 1) is that the rolling mill becomes very stiff. Control methods for fitting the roll gap to the strip profile are necessary. In order to obtain good flatness, Cluster uses two main control methods to modify the effective roll profiles. In the first method, you grind the first intermediate rolls (i.e. four rolls near the work rolls, see Figure 1) to a tapered diameter profile and shift each roll in the axial direction. In the normal case, the strip profile is symmetrical and the strip has a centre position in the mill. In this case you are working in such a way that the upper rolls have the same amount of shifting (at the same time) as the lower rolls, but in the opposite direction.

Cluster also gives the opportunity to make calculations where the lower pair of rolls and the upper pair of rolls has a different shifting, or where each roll has an individual shifting. The second method normally affects two or all four upper backup rolls (see Figure 1). However, there are roll constructions where there are controls on all four upper backup rolls. Cluster manages both of these cases. The backup rolls do not have the solid shape the other rolls have; they are instead segmented and consist of a number of bearings, threaded on a centre axis, see Figure 2. Besides these two main control methods, Cluster can also take roll bending of all the intermediate rolls and the work rolls into account, as well as tilting of the mill.

Figure 2 - Segmented backup roll.

Cluster calculates the elastic deformation of the rolling mill based on the force between the strip and the work rolls while rolling. The rolling force is assumed to have a vertical alignment against the work rolls; thus, you must assume symmetry between the upstream and downstream rolls. Therefore, it is enough to model the six rolls of Figure 1. However, the deflections of the top and bottom clusters of rolls are usually different and calculated separately. Cluster calculates the roll gap profile (which is assumed to equal the thickness profile of the strip after rolling) from the deformation of the mill. The strip profile will affect the reduction across the strip, which affects the allocation of the rolling force on the work rolls. This in turn affects the deformation of the mill, which affects the shape of the roll. You can see that the calculations must be done iteratively. Cluster can solve calculations for a number of passes (max: 20) on a strip. The thickness profile after rolling is used as the thickness before rolling in the next pass. Cluster is a powerful tool for simulating both 12-high and 20-high rolling mills.

SYSTEM REQUIREMENTS
The program has a user-friendly shell with graphics and is implemented for IBM compatible PC
with Microsoft Windows 95 and Microsoft Excel 97 or higher. A minimum of 3MB of HD space
is required.

CLUSTER DEMO
Cluster Demo is a demonstration of the simulation program Cluster. The program package of
Cluster Demo is written for MS Excel and is therefore used as an Excel document. Cluster Demo
uses a modified program module, Cluster.exe, with the user interface implemented for MS Excel.
The program includes models for simulations of elastic deformation of the roll cluster during flat
rolling in 20-high mills. Such powerful control parameters as taper roll shift, U roll positioning
and roll profiles are all included in the program package. Advanced calculations are made to
provide the following useful results:

• Strip profile
• Strip flatness
• Stress distribution
• Force distribution at all roll surfaces

• The diameters of the different rolls
• The roll body length of the rolling mill
• The axial positions of the saddles
• The demo program is limited to calculation of a single rolling pass.

• MS Windows 95 or higher, or alternatively MS Windows NT 4.0 or higher
• MS Excel 97 or higher
• 3-MB HD

1. Download Cluster Demo by activating the hyperlink below. (If you are using Netscape'sbrowser: hold down shift while activating the hyperlink) Download cluster demo version1.0
2. Run the self-expanding executable file, cluster_demo.exe by double-clicking on its icon inyour file manager (for example Windows Explorer).
3. Double-click or run the file, Cluster.xls. (The Cluster Demo user interface is an Excel document).

Download Cluster Demo
 

It is a good idea to use copies of the original Excel document, so that you can easily restore the
original input data and results. Modify the data for the strip or the rolling mill and calculate the
results until you get reasonable flatness! It may be interesting to optimise the settings for different
strip thickness profiles.
This way it is possible to understand how to optimise the taper profile and axial shifting of the
first intermediate rolls. It is also possible to optimise the settings of the backup-roll saddle
bearings.
For more information about Cluster or Cluster Demo, please contact:
Patrik Sidestam This email address is being protected from spam bots, you need Javascript enabled to view it

- Program for temperature, heat transfer and furnace control systems

STEELTEMP^®
The STEELTEMP^® program comes in three main editions, edition 2D for flat and round products, using the finite-difference 2D technique, edition GR for flat, oval, flattened oval, diamond, square, round, false round and box products, using the finite-element 2D technique, and edition 3D for flat products, using the finite-element 3D technique.

Dr. Bo Leden is responsible for the development of the different editions of STEELTEMP® and offers of licences which give the legal permission to use these editions. Contact person: E-mail This email address is being protected from spam bots, you need Javascript enabled to view it . For information about the numerical solution of the Fourier's heat equation see IFE, Norway.

STEELTEMP® 2D
STEELTEMP® 2D is a program for temperature and heat-transfer analysis during casting, cooling, stripping, heating, rolling and forging. Temperatures and densities of heat flow rate are calculated in a cross section of the steel. Composite structures such as liquid steel in an ingot mould, a stock on a ceramic hearth, etc. may be analysed.

In the reheating furnace models, the heating curve of the stocks and oxide scale formation can be calculated, either from specified furnace temperatures - the simple heating model - or from the geometrical and thermal description of the furnace, fuel and combustion air flows, etc., using the complex heating model or the dynamic heating model. Special software for calibration of the heating models in the FOCS furnace control system has been implemented. Models for induction heating of stocks for rolling are available as well. Combustion calculations can also be performed using the program STEELTEMP® 2D.

The mathematical furnace models are compatible to the online mathematical models used in the furnace optimization control system for reheating furnaces FOCS-RF. The STEELTEMP® programs is implemented on PCs for Windows 95/98/NT/2000/XP.

STEELTEMP® 2D has MS Excel-based interfaces STEELGEN® 2D, QUENCHTEMP and FORGETEMP for heating, rolling, quenching and forging, respectively. These interfaces are used for pre- and postprocessing of data in connection with temperature simulation with STEELTEMP® 2D. The interfaces use a number of spreadsheets in Excel where the user can enter process data and define the process conditions. The input generation is made in a user-friendly graphical environment. A number of program settings are automatically made in order to facilitate the input generation for the simulation. The input data given by the user is transformed into an input file by visual basic commands. This input file is used for STEELTEMP® 2D simulation. After running the simulation the results can be presented in diagrams and data tables with the interfaces. Further analysis of the results can be done with ordinary Excel functions.

More information: Scanheating_85 (1985), Scandinavian Journal (1986), Institute of Materials (2002)

STEELTEMP® GR
The user can construct a pass schedule for eight different geometries of the cross section of the bar. The program will then calculate the temperature distribution in the cross sections of the bar or wire during groove rolling, cooling and water spraying.

STEELTEMP® 3D
In the reheating-furnace models, the temperatures of the stocks can be calculated in three dimensions, either from specified furnace temperatures - the simple heating model - or from the geometrical and thermal description of the furnace, fuel and combustion air flows, etc., using the complex heating model or the dynamic heating model. Special software for calibration of the heating models in the FOCS furnace-control system has been implemented.

Nonuniform heating of stocks caused by radiation shadowing effects from the skid pipes, the contact between the wearer bars and the stocks, baffles in the furnace and end effects in the stocks can be analysed using STEELTEMP® 3D.
In particular it is possible to determine

• magnitudes of skid marks
• head and tail end uniformity of stocks
• cross-sectional uniformity of stocks

More information: Revue de Metallurgie (1999).

– Temperature, heat transfer, furnace control systems

FOCS
Dr. Bo Leden is responsible for the development of the different FOCS systems and licences, which give the legal permission to use these editions. Contact person: E-mail: This email address is being protected from spam bots, you need Javascript enabled to view it

FOCS-RF

FOCS-RF is a supervisory system for fuel optimization of reheating furnaces which controls the set points of the different control zone temperatures based on predetermined ideal heating curves. The system contains functions for material tracking, fuel optimization and delay control, pacing, rolling-mill adaptation, and programmed start-up and turn-down control. The heating curves of the stocks are calculated online using measured furnace temperatures, fuel flows to the control zones and data from the material tracking system. The difference between the calculated and ideal heating curve gives via a feedback controller a fine adjustment of the control-zone-temperatures set points.

For three-dimensional calculation of the stock temperatures, an online version of STEELTEMP® 3D has been developed. Using a three-dimensional model, the temperature distribution within the slab can be obtained with more resolution than with the existing one- or two-dimensional models, taking into account shadowing effects from the skid pipes, contact between the wearer bars and variation of furnace temperature in width direction.

The system gives fuel savings of 10-15%, reduced scale formation and improvements in material properties.

The system is sold worldwide on a license basis by ABB Automation Technologies AB. So far, more than 50 systems have been sold.

More information: Scandinavian Journal (1986), Scanheating II (1988).

FOCS-BNF

The control system FOCS-BNF is based on the heating model of STEELTEMP® 2D to predict the temperatures in the ingots heated in a bogie hearth furnace. The system is installed in four bogie hearth furnaces used for high temperature annealing and heating of ingots with weights up to 45 tonnes at Uddeholm Tooling AB forging plant.

More information: Steel_Times_(1997).

Software for roll profile, flatness, rolling force, elastic deformation and temperature distribution.

CROWNOFF

The program package can be used for offline simulation of rolling in 4-high plate mills, hot-strip mills, cold-strip mills and temper mills. Roll separating force distribution, plate/strip thickness profile, work-roll thermal expansion and wear profile are calculated for final calculation of the flatness. Control methods like VC (variable crown) and selective roll cooling can be simulated. The program parts, WASP (elastic deformation), TREX (thermal expansion), WEAR (wear), FRICTION-HILL (roll gap parameters) and SLABTEMP (slab temperature), are available as separate programs. The program package has a user-friendly shell with graphics and is implemented for PCs with Windows operating systems. There are also versions for UNIX and VMS operating systems.

CROWN4

The program package can be used for offline simulation of rolling in 4-high plate mills, hot-strip mills and cold-strip mills. Roll separating force distribution, plate/strip thickness profile, work-roll thermal expansion and wear profile are calculated for final calculation of the flatness. Control methods like VC (variable crown), CVC and other roll-shifting methods, PC (pair cross) as well as selective roll cooling can be simulated. Roll pass schedules can be generated for plate mills and tandem hot-strip mills. The program parts, WASP (elastic deformation), TREX (thermal expansion), WEAR (wear) and SLABTEMP (slab temperature), are available as separate programs.

CROWN4 is developed from CROWNOFF. The main improvement is the simple and flexible input. The program package has a user-friendly shell with graphics and is implemented for PCs with Windows operating systems.

CROWNON

Program package for online calculation of plate/strip thickness profile, temperature, thermal and wear profile of rolls in hot rolling of plates and strips. The program is based on the off-line version, CROWNOFF. The different program parts in CROWNON can be used separately. CROWNON may be used to control flatness in plate and strip rolling and for online pass schedule generation. Available for the VMS and Windows operating systems.

CROWN 426

Program package for simulating thickness profile and flatness in flat rolling. Work-roll profile is calculated with thermal expansion and wear taken into account. The elastic deformation of rolls and the deformation of the rolled material are calculated for both hot- and cold-rolling mills with 2 to 6 rolls. Force distributions between rolls are calculated. Simulations of 6-high mills with adjustable intermediate and work rolls, 4-high mills with adjustable work rolls, 5-high mills with an extra roll adjusted in relation to the mill's symmetry line and other unsymmetrical mills can be performed. Simulation of tandem mills with up to 7-roll stands is possible. The model takes into account strip tensions between roll stands and between the last stand and the coiler.

Related programs, NSASP (elastic deformation), TREX (thermal expansion) and WEAR (wear), are available for separate simulations.

For rolling of bars, wire and narrow strip, MEFOS has a three-stand continuous rolling mill in-line with the reversible rolling mill, suitable for both cold and hot rolling. Coilers and decoilers are available for rolling narrow strips, and for long product rolling the stands can be tilted 45º in order to simulate horizontal and vertical stands. Product dimensions in the mill are Ø 5.5 mm up to Ø 32 mm and for strip max 100 mm in width. High-pressure on-line cooling for thermomechanical rolling is also available. The cooling, that can deliver water pressure between 200 and 5 000 kPa, can be applied either between stands or after the last stand.

The rolling stock is heated in an electrical muffle furnace in front of the mill or transferred from the reversible rolling mill which has excellent measuring facilities. This makes it suitable for advanced research of both bar and strip rolling.

Each stand can be run as 2- or 4-high for cold strip rolling and the two available lubrication systems can be used for lubricant testing and evaluation. One system is designed to apply lubricants individually and has a higher lubricant pressure capacity, whilst the second system is designed for multi-testing where several lubricants can be applied during the rolling of a single strip. The lubricant application is flexible so that strip and/or roll-gap lubrication can be arranged. Many different flows are available simply by changing nozzles.

For technical details see brochure (page 22).

• Melting and casting steel and other metals.
• Casting and direct rolling/forging.

 For technical details see brochure (page 21).

When there is a need for accurate speed control and/or work piece positioning, a special water-cooling line is available.

The line contains a descaling unit, and upper and lower cooling banks with replaceable nozzles. The hot work piece is placed on a carriage which is run through the cooling equipment at a constant speed.

For technical details see brochure (page 20). 

Rolling with thermocouples mounted in the slab

The 2- and 4-high reversible rolling mill is equipped for rolling both flat and long products, and using a special design, the roll package can be changed easily from 2-high to 4-high and vice versa. Roller tables, water cooling equipment and a roller hearth furnace are in-line with the mill, whilst heating prior to rolling can be carried out in any of the reheating or heat treatment furnaces. The walking beam furnace, the induction furnace and the roller hearth furnace are directly connected to the mill via roller tables.

The rolling mill has exceptionally good measuring facilities which make it suitable for advanced research. Billets, blooms and small slabs can be rolled within the mill.

Technical data - Reversible rolling mill and auxiliary equipment

Roller table cooling banks

The forging plant consists of a 5 MN, underbuilt high speed hydraulic forging press and a rail bound forging manipulator. The computer-controlled press, combined with good measuring capabilities (including tool position, manipulator position, press force and ingot temperature), is well-suited for high-quality production and advanced research projects.

Technical data - Forging equipment