welded pipe mill,welded tube making machine,slitting line
Taiyuan HKX Metallurgy Complete Equipment Co., Ltd. is a high-tech enterprise specialized in designing, developing and manufacturing the complete equipment such as spiral welded pipe mill, straight seam welded pipe production line, section steel mill and slitting line.
Our leading product is pipe making machine like welded pipe mill, section steel mil and sltting line, etc. The technology and quality of our products are as good as that in Taiwan or Korea. But the price is far lower than that in Taiwan or Korea...
TAIYUAN HKX METALLURGY COMPLETE EQUIPMENT CO., LTD.
Add: Floor. 8th, Zhonghengjian Building, No. 36 Industrial Road, High-tech Zone, Taiyuan, Shanxi, China
Email: [email protected]
setting up the welding section on tube and pipe mill lines
Which is more important, Weld Integrity, or Welded Tube Size?
A trick question? Not really, as a point is needed to be made here concerning these two topics, Weld Integrity, and Welded Tube Size.
The correct answer is, "BOTH".
Look for continued articles to follow on the proper set up of the sizing section here on Roll-Kraft's web site, which offers the most comprehensive, informative and interactive technical information in the industry.
Written by: Robert A. Sladky, Vice President Tube Mill Engineering
welded roll forming system versus tube mills: whats the difference?
The welding of streel strip into a product, such as round tube or pipe, box frames, and structural members, is a multibillion-dollar industry that had its beginnings more than a century ago. Many items that we use today, like furniture tubing, oil pipe, and fuel lines, are manufactured on welded tube mills.
In the last 20 years OEMs have been asked to apply the principles learned from tube mills to the much larger roll forming processing market. This has created another technology area today known as welded roll forming.
Companies may move from nonwelded open shapes to welded roll formed shapes for many reasons. Welded roll formed shapes have structural strength and integrity, help eliminate secondary operations in downstream manufacturing, and can offer savings in steel and construction labor. While there are benefits, there are also costs, which typically involve an investment in capital equipment and skilled people who know how to use the technology.
These questions, asked often within the industry, are plagued with many conditional aspects that cloud the final answer. Intricate details often are required to help machine builders focus on the best option.
In the classic sense, a tube mill is a kind of welded roll form system; however, not every welded roll form system is a tube mill. Tube mills are welded roll form systems that have been fine-tuned to run a specific diameter range, typically at fast speeds (see Figure 1).
On all welded roll form systems, including tube mills, welding can occur with processes like high-frequency (HF) induction, HF contact, electric resistance, and laser beam welding. For the sake of this discussion, it is assumed that the correct welding process has been determined based on the specific material requirements.
Figure 2 shows the typical forming flower of a tube mill forming the strip into a round product just before welding. From there the round product can stay round or can be sized or reshaped into a square or rectangle.
In a tube mill, the forming machine forms the strip into a round, weldable product. The forming machine has two main parts: breakdown and fin-pass sections. Once welded, the tube can be left round, though it undergoes further forming to size it to a more accurate outside diameter. The sizing section shown in Figure 3 has round roll stands with specialty reshaping stands toward the exit and a double turks-head to finish. Used for straightening, a turks-head has two pairs of rolls, one arranged vertically and the other horizontally.
Defining a welded roll forming system is a little more difficult. Again, in the classical sense, a tube mill is one kind of a welded roll forming system. But if someone refers to a welded roll forming system, that person is probably not talking about a tube mill, but other roll forming machines able to form various, often highly complex shapes to within tight tolerances.
Much like forming on the tube mill, with breakdown and fin-pass sections, welded roll forming systems have a similar forming setup, with the fin-pass section occurring in the last few stands before welding (see Figure 4).
When working with nonround shapes, such as a step beam (see Figure 5), the roll forming system tends to form the shape as is before welding. Some in the industry call this near-net-shape forming. Others call this the form square-weld square process. Once the shape is formed and welded, most recommend at least two additional passes to work the welded shape once more to finalize the dimensions.
This specialty pass progression has led tube mill builders to design systems with a given diameter range to have between five and nine driven forming passes, with their sister idle side passes. The actual pass count often is a function of the ratio of the workpiece diameter to the material thickness, material yield strength, as well as the minimum to maximum range for both material OD and thickness.
Welded roll forming mills tend to have mostly driven passes, though using idle side passes is becoming more common. Many factors come into play when determining the most robust pass count for stable welding. Pass counts depend not only on material wall thickness and yield strength, but also on the overall complexity of the shape to be formed. The pass count also depends on material movement during the process, as well as the experience of the roll tooling designer.
To determine the best machine, consider the strengths and weaknesses of each. Tube mills specialize in simple shapes. Besides round shapes, theyre capable of producing squares, rectangles, and ellipses.
If youre looking to form a few complicated shapes, the tube mill may not be the best choice. Forming some shapes on the tube mill simply isnt possible, but a welded roll forming mill can form highly complicated shapes quite readily.
Also consider the outside corner radii of those shapes. In some cases, a tube mill can form those radii down to 2 times the material thickness, but this isnt typical. Usually a tube mill can form radii down to between 2.5 to 3 times the material thickness.
Welded roll forming mills have a different tooling setup that allows for tight, accurate radii. Specifically, it has to do with how the forming rolls engage the material on the corner. On a welded roll forming mill, both the female and the male roll engage the corner, making forming very exact. Typically, radii can be formed down to less than 2 times the material thickness.
Also consider the consistency of the corner radius, as measured from corner to corner on the roll formed product. Shapes formed on a tube mill may have discrepancies between opposite and/or adjacent corners. This occurs because of one-sided bending, with just one roll (not both male and female) fully engaged with the material.
Male and female roll engagement in welded roll form systems has another benefit: It helps produce consistent flat sides or features, with no crowning or other reshaping. Because tooling on a tube mill gives the workpiece no inside support, flat sides or features tend to reshape during the process and emerge from the tube mill with a crown.
Also take into account any pre-punching operations that a job might benefit from or require. Punching typically is not recommended on tube mills. This is because of inconsistencies with so-called round-to-shape material movement. It can be very difficult to lock the hole location in a round shape and then reshape it into a square, hoping the hole ends up in the correct position. Moreover, punched holes may warp during the reshaping phase.
Pre-punching in welded roll forming is usually better because it allows you to accurately locate hole features. The punched holes also tend to hold their shape during forming, if those holes are put in the right location. If the hole is near a corner, however, the hole shape still can change.
Finally, consider processing speed. This hinges mainly on pre-punching operations. Since pre-punching is not normally performed on tube mills, these mills have been designed to run up to 750 feet per minute (FPM), depending on the product OD and wall thickness. If a pre-punching job is running on a welded roll forming mill, processing speeds typically are 100 FPM or less, though they can be improved with special tooling like a rotary pierce tool, which looks like a roll with punches sticking out of it. These punch or pierce the material as the roll rotates. (Rotary piercing does have limits and may not work in some applications.)
If pre-punching is not required, then a welded roll forming system can process at the same speeds as a tube mill. To achieve and maintain these speeds, however, a welded roll form system needs some tube mill specialty equipment added, such as an accumulator and high-performance cutoff.
So again, which is best? If you have only simple shapes to form, a tube mill may be the way to go; if you have complex shapes with multiple radii, holes, and other features, a welded roll forming system is the way to go.
But what if you have a simple shape with tight tolerances? What if those radii need to be consistent from corner to corner? What if you need sides to be precisely flat, with no chance of crowning? In these cases, a welded roll forming system may be more suitable for the job, unless product specifications can be changed.
tube mill components | olimpia 80
STRIP EDGE PREPARATION UNITS
These devices have been designed and manufactured in order to meet the quality requirements of the lines with LASER welding system and in any case to ensure optimum quality of the strip edges if it was specifically required also in other applications.
There are two systems:
These equipment allow to eliminate totally the line stops due to coil change. Olimpia offers a wide range of models which are able to meet different production needs and are suitable for variuos type of material.
HORIZONTAL STRIP ACCUMULATOR
This accumulation system is designed for high speed production lines and consent to accumulate also strips with very high thickness. The maximum strip loading speed is 400 m/min.
DOUBLE WHEEL STRIP ACCUMULATOR
This system is mostly indicated for thin wall products and high production
speeds. The equipment consent to load the strip at a maximum speed of 500 m/min and up to a limit weight of 80 tons.
The strip tension is electronically controlled by a dancing roll which is placed at the entry of the line.
STRIP VERTICAL ACCUMULATOR FOR LASER MILLS
This new vertical strip accumulation unit has been specifically studied for its use on laser welded tube mills, with speed up to 30 m/min.
This is a new solution that allows a secure control of the strip at medium speeds, assuring the complete absence of yielding and damages to the material.
STRIP VERTICAL ACCUMULATOR FOR HIGH FREQUENCY MILLS
Strip accumulation system studied for high production speed tube mills. This equipment permits the strip accumulation at a maximum speed of 400 m/min.
NEW BEAD GRINDER WITH FLAP WHEELS
A considerable increase of the use of laser welding has solicited the development of a machine for external bead grinding, which is indicated for a different configuration of the laser welding seam and for the increased production speed. A new equipment has been engineered which, thanks to the use of special flap wheels, permits to eliminate the bead at high speeds without scratching the surface of the tube. The work is done in a completely dry condition, with considerable reduction of maintenance times and costs. Furthermore, the device for the automatic wearing compensation allows to obtain a completely homogeneous removal.
SCARFING UNIT FOR HIGH FREQUENCY WELDED TUBES
This system makes use of two tools with hard metal tips.Tool adjustments are electronically controlled, such as the automatic positioning at the production start and the automatic tool wearing compensation.
Olimpia 80 offers bead rolling machines for the inside removal of the weld bead that can guarantee an high finish quality and the greatest stability. This bead roller is suitable for Tig and Laser welded tubes, with inside diameter fron 14 mm to 220 mm.Tube speed: max. 10m/min.
NEW MAGNETIC BEAD ROLLER
This equipment, specifically designed for laser welding Tube Mill, gives the advantage of no mechanical connections between mandrel and any external support: the wire rope moving the mandrel in the traditional hydraulic system can be totally eliminated.
The internal mandrel works thanks to the magnetic field generated by a permanent magnet sliding on rails in an alternate rectilinear motion. This permits also the consequent reduction of the minimum inside-rolling diameter.
These cutting equipment are design for cutting tubes at high production speeds.
An automatic control system allows to optimize blade positioning according to the tube diameter and thickness, setting the speed of feeding and rotation of the blades.
This system is able to optimize and increase the number of cuts.
NEW FLYING SHEAR CUT OFF
Tube cutting is operated by means of two tools which are hydraulically operated and controlled by the latest electronical technologies.
The whole process is controlled by one hydraulic cylinder which guarantees the perfect synchronization of the cutting cycle and to obtain optimum conditions on the cutting time. In addition the employ of hydraulic systems assures an easy use of the machine and a reduction of maintenance times and costs, compared to the use of mechanicalsystems.
The movements of the cutting carriage are electronically controlled to guarantee the automatic adaptability to the tube speed.
Moreover an inclination system allows the automatic tool centring on the tube angle in case of production of square and rectangular profiles.
This equipment is offered in two different models covering ranges from 15 to 76 mm O.D. and from 30 to 114 mm O.D., with wall thicknesses from 0.8 mm to 3.5 mm.
DOUBLE BLADE VERTICAL CUT OFF
This new machine has been designed for the in-line cutting of large dimension tubes, in round, square and rectangular shapes.
The innovative system with parallel movement of blades allows to reduce the cutting cycletime and to make easier the set up of the blades.
Moreover, thanks to the new universal tube blocking system, the vices change is not necessary for square and rectangular profiles and this consents a great reduction in costs and time.
DOUBLE BLADE FLYING CUT OFF
This cutting machine, especially designed for large pipes.
The machines works with 2 blades, mounted on slides and placed on a rotating support, penetrate into the tube with material removal and make the complete product cutting by means of the support rotation.
Tube is hydraulically clamped and the complete cutting group is mounted on a sliding carriage which is complete with electronic movement device that assure a cutting precision of +/- 1 mm.
A PLC controls the machine operations and automatically determines, fixing some data regarding the product and the used blades, the carriage and blade speed and the blade position, making the cutting programming and process fast and easy.
Olimpia 80 produces equipment for in-line brushing of round stainless steel tubes.
Different models are proposed, with use of two or three brushing heads in different lenghts, according to the type of product and to the line speed.
3 HEAD PLANETARY BRUSHING MACHINE
This new equipment, thanks to the addition of one brushing head, has 1/3 higher removal capacity than the traditional machines.
It is mainly suitable for big tube size.
Machine for in-line tube end deburring by means of metal tools making the automatic inside and outside removal of burr.
This equipment is used for tubes from 10 to 76 mm O.D., it is directly mounted on the unloading table of the mill and the tube movements are fully automatic.
Machine for the tube ends finish by means of stainless steel brushes.
Brush position is vertically and horizontally adjustable, while their speed is controlled by inverter.
Tube movements on the roll ways and working speed are automatically controlled by PLC.
erw tube mill line | electric resistance welding pipe mill line
Electric resistance welding tube mill is used: For low-pressure fluid transmission, machinery manufacturing, electric power engineering, etc. LF19-76 High-Frequency Tube Mill Production Line / high-frequency straight seam pipe making machine / ERW Tube Mill Line is designed to produce welded pipes of 19mm76mm O.D. Of round pipe and Round pipe 0.6mm2.5mm, Square pipe 2mm in Wall thickness.
Raw material (steel coil) uncoiling shearing and butt-welding material accumulating non-power leveling mill-forming high-frequency welding removing burrs outside of weld seam Zinc spraying cooling sizing roughly straightening fixed length cutting run-out table
One set of guide roll stand for controlling direction of pipe seam to insure pipe seam flatly and straightly entering into extruding rollers.1 set of extruding roll stand for controlling weld seam to realize successful welding.Two sets of scraper frame for scraping outside weld seam
The tube is produced by the Electrical Resistance Welding (ERW) of the longitudinal seam. By using a pre-coated steel strip [zinc coating (galvanized), aluminum coating (aluminized) or Zn/Al Alloy Coating], a tube with enhanced corrosion resistance can be produced. During the welding process, the external coating around the weld area damaged by the heat generated around the weld area and the subsequent tooling operation, and should re-protected this area of the tube will corrode.
The re-protection of this weld damage gets by using a metal sprayed deposit with a material that affords similar corrosion resistant properties to the strip pre-coat. This method is in line with the repair is the only way available which offers the flexibility of producing tubes with zinc, aluminum or Zn/Al coatings.
Sizing device: Mainly fine shaping pipe after welding and controlling size accuracy. Each 6 sets of horizontal roll stand, vertical roll stand and drive gearbox, 12 sets of universal shaft.(structure same as forming device)