DE10008693A1 - Concrete reinforcing steel method/machine for concrete steel rolling mill produces round strips containing smooth/ribbed connected bars, straightened, slit, and cut-to-length - Google Patents

Abstract

The leading pass section is initially rolled in several passes to a rectangular strip, than an oval strip, and then a round strip. This contains any number of round bars, smooth or ribbed, next to each other and connected by longitudinal ribs. The round strip is cooled and then moved to a straightening, slitting, and cut-to-length plant, to produced individual bars. After passing through a water cooling and air compensation section, the round strip is initially fed into a winding unit, to produce heavy coils, which are later moved to the individual bar processing plant.

Description

State of the art

Fig. 2.1 and 2.2 show reinforcing steel production plants according to the current state of the art consisting of steel mill, billet continuous casting plant and bar steel / wire rolling mill.

The overall system consists of the following system components:

• 1. Steel mill
• 2. Multi-core continuous caster with oscillating mold for production of square, rectangular or round billets usually in the dimensions of surfaces same cross-sections corresponding to a square of 100 to 150 mm edge length and a length of about 10-12 m.
• 3. Cross-cutting system for dividing the endless strands with one pair of scissors per wire.
• 4. Cross transport / cooling bed with feed roller table to the rolling mill furnace
• 5. Rolling mill furnace.
• 6. Rolling mill with
  • 1. 6.1 Descaling
  • 2. 6.2 Rough mill with 6 stands, stands 1-6 , in H or HV arrangement and a pair of scissors
  • 3. 6.3 Intermediate line with 6 scaffolding, scaffolding 7-12 , in H or HV arrangement and scissors.
  • 4. 6.4 Prefabrication mill with 4H and 2V stands, stand 13-18 , with a maximum of 4 slit devices behind stand 18 .
  • 5. 6.5 finishing train - maximum of 4 cores, each with 1H and 1V framework for an oval and circular stitch
  • 6. 6.6 water-air cooling section, one per wire, for thermal treatment z. B. drive similar to Tempcore, Thermex or similar heat treatment.
  • 7. 6.7 Cooling bed casserole with scissors, brake driver and pair of folding troughs per wire for braking the bars divided on the cooling bed length at high running speeds of approx. 30 m / s., The cooling bed length being a multiple of the sales length of the bars.
  • 8. 6.8 cooling bed as cross transport z. B. rake cooling bed for simultaneous cooling and preparation of the heat-treated bars in cooling bed lengths to cold shear temperature.
  • 9. 6.9 cross-cutting system z. B. Cold scissors for dividing bars with cooling bed length in layers collected on sales length.
  • 10. 6.10 Transverse transport of the rods with sales length to the bundle and binding system for collecting rods in layers into bundles and for binding the bundles.

The manufacturing process and the associated systems and machines developed from the single and multi-core production of steel bars or wire by rolling, whereby the following measures were taken to increase the production for reinforcing steel:

• 1. Reversing and semi-continuous rolling mills developed into full cont nuclear rolling mills
• 2. Final rolling speeds were increased up to a limit with that Construction of brake systems of the bars in the cooling bed roller table with Brake sliders or maximum controllable outlet speed the wire block for wire in coils as the wire passes through Guided tours were given.
• 3. Final rolling speeds were further increased by developing new ones Braking systems with brake drivers and folding channels in the cooling bed overrun for the Er increase of the stabilization running speed to approx. 30 m / s for 8 mm ∅ concrete rib steel or more than 120 m / sec from the wire block for coils Development of suitable guide and water cooling lines and winding layers.  Further increase in the outlet speed from the last roll stand fail due to operational safety, since the roller bars with high running edges vibrations through guides tend to break out during passage.
• 4. Increase in production by slides (longitudinal parts) according to stand 18 on 2, 3 or 4 cores by increasing the total weight per meter of the cross-section emerging from stand 18 compared to single-core finish rolling while maintaining the exit speed of the rolling rod. Slides also reduce the degree of stretching from the tapping cross-section to the finished cross-section and thus the number of stands required compared to 1-wire rolling with the same tapping cross-section

Disadvantages of today's technology

• 1. The slitting takes place in the warm state at the same time high running speed of the bars and the run-up of the single cell bars the cooling bed also takes place at high speeds of approx. 30 m / s. By manipulating the bars during high longitudinal transport speeds such as B. sledging, braking and handing over the bars There are frequent interferences on the cross transport because of the high Speeds are not mastered technically and to the end break the rods. In addition, the necessary for this Machines are complicated and therefore expensive and prone to failure.
• 2. The rolling out of a billet with a large cross-section, the is much larger than the piercing cross section required for metallurgy to a high number of roll passes and thus with fully continuous Chen rolling mills to a high number of rolling stands and thus unnecessarily high investment and operating costs, which also through system-related high speeds of the rolling rods even further increase.

Subject of the invention

Fig. 3.1 and 3.2 show a change according to the invention in the known rolling process on a conventional rolling mill as shown in Fig. 2.2 treated material in several production steps. From a tapping cross section z. B. Square, in several primarily horizontal frames, a rectangular strip cross-section in front of the two profiling stitches is also rolled in 2 horizontal stands, first the oval strip and then the round strip with several circular cores lying next to one another and connected by longitudinal ribs with transverse ribs or a smooth surface, the round strip consisting of any number of cores . The round belt can run through a water cooling and air equalization section before it is cut to length in the cooling bed without slitting. The cooling bed length is a multiple of the sales length.

The round belt with cooling bed length is braked in the cooling bed casserole and onto the Cooling bed placed where it transports for further cooling and preparation becomes.

When the round belt has reached the target temperature, the round belt runs into one Multi-core straightening machine, then in a slitting line and then closed a pair of cross-cut scissors, so that after these 3 process steps individual straight Rods with longitudinal ribs and transverse ribs or smooth surface in sales lengths available.

The individual sticks are collected, bundled and made ready for dispatch.

Fig. 4 shows another reinforcing steel production plant according to the invention.

In contrast to the current state of the art, the following principles are applied:

• 1. Near-dimensional casting with high casting speeds for single core continuous casting rolls with smooth rectangular or oval prepro filleted strip casting cross section.
• 2. Minimization of the rolling work and number of roll stands to approx. 2 or 3, since only profiling is carried out by the rectangular flat strip or the oval strip in front. After profiling, there is a profile strip with a large number of individual round profiles connected to the longitudinal ribs.
  This round profile belt has a high weight per meter, which is why even low outlet speeds lead to high productions. Small outlet speeds increase operational safety and reduce investment and operating costs.
  The profile strip is thermally treated in a continuous process at low speeds by targeted surface hardening and tempering as well as cooling to the straightening temperature and fed with straightening temperatures after the desired heat treatment either to a straightening and slitting line or only to a cross-cutting line and coiler without slitting. This creates heavy bundles with ribbed or smooth round belt, which are reeled off on rebar processing plants ( Fig. 5), straightened, slit, cut to length to z. B. to be welded to reinforcing steel mesh. The reeling, straightening, longitudinal and transverse parts can "inline" in the rolling mill or "offline" in a system z. B. in a rebar mesh plant.
  Now that the profile tape has been heat-treated, it is divided lengthways.
  This system, like the systems shown in FIGS . 3.1 and 3.2, can also have a cooling bed and the associated system parts shown here. The longitudinal division takes place in the area of the longitudinal rib of the rib steel. Reinforcing steel can also be produced according to FIG. 6 according to the same principle of the rolling of round strips on a hot strip mill of today's design, the last two stands of the hot strip mill taking over the function of the stands in sections 2 and 3 in FIG. 4.1. The rest of the process can take place on the known parts of a hot strip mill.

Reference list Fig. 3.1

1

Tapping cross section

2

Sand cross section

3rd

Oval band

4

Round belt
Rolling mill
Water cooling and compensation section
Cooling bed shears
Cooling bed
Roller straightener
Slitting line
Cross cut shears
Rod collecting and bundling device
Finishing line

Fig. 3.2

1

Flat ribbon

2

Oval band

3rd

Round belt
Rolling mill furnace
Billet welding machine
Descaling
Roughing stand group
Cross cut shears
Intermediate scaffold group
Cross cut shears
Finishing stand group
Water cooling and compensation section
Cooling bed shears
Cooling bed
How

Fig.

3.1 Position 5-9

Fig. 4.1

A flat ribbon cast
B Rolled oval band
C Rolled round strip
D Round band waistband
Continuous caster
Roll forming stand 1
Roll forming stand 2
Water cooling and compensation section
Straightening system
Cross cut shears
Decoiler

Fig. 4.2

A cast flat ribbon - omitted compared to 4.1
B Oval strip cast and not rolled as in 4.1
C Rolled round strip
D Round band waistband
Continuous caster
Roll forming stand 1 - not applicable compared to 4.1
Roll forming stand 2
Water cooling and compensation section
Straightening system
Cross cut shears
Decoiler

Fig. 5

A round tape unwound
B round belt directed
C Longitudinally divided = single round bars endless
D single round rods finally
E Reinforcing steel mat
Appendix 1 - Decoiler round band coils
Attachment 1 straightening machine round belt
Appendix 1 - slitting shear
Appendix 1 - Cross-cut shears
Appendix 1 - Reinforcing steel mesh welding machine
Appendix 2 - with machines 1-4
a strand a = rod a
b strand b = rod b
c strand c = rod c
d strand d = rod d
e strand e = rod e
f strand f = rod f
g strand g = rod g

Fig. 6

A slab cast or rolled
B Slab with rolling temperature
C ribbon
D oval band
E Round strip rolled at the rolling temperature
F Round band heat treated
G round band
Rolling mill slab heating furnace
Hot strip mill 1
Hot strip mill 2
Hot strip mill stand 3
Hot strip mill stand 4
Hot strip mill stand 5 = oval strip stand
Hot strip mill stand 6 = round strip stand
Water cooling stretcher
Decoiler

Fig. 1 DIN 488 - sheet 2 picture 1 and 2

Fig. 2.1 and 2.2 layout of a rebar plant according to the current state of the art

Fig. 3.1 and 3.2 layout of a concrete steel production plant according to the invention as an extension of a plant according to the current state of the art

Fig. 4.1 and 4.2 layout of a concrete steel production plant according to the invention after the Gießwalzprinziep

Fig. 5 layout of an offline slitting line for slitting a heavy bundle from multiple round band according to the inventive method

Fig. 6 layout of a hot strip mill of today's type, on which, in addition to conventional hot strip, round strip in heavy bundles are produced by the method according to the invention.

Claims (5)

1. Processes, plants and machines for a partially conventional and partially new inventive rebar mill characterized in that the tapping cross-section is first rolled in several passes on a rectangular belt, then on an oval belt, then on a round belt in which any number of round bars, smooth or ribbed, side by side connected by longitudinal ribs. The round belt is first cooled and then fed to a straightening, slitting and cross-cutting system, so that the individual bars are only available after this. 2. Like 1 . but with the difference that the round belt is not supplied to a cooling bed but to a reel device after the targeted water cooling and air equalization section, on which heavy bundles are produced. These, heavy bundles of round strip can be unwound and then fed to a straightening, slitting and cross-cutting system. 3. Near-dimensional casting with high casting speeds for continuous casting of smooth rectangular strip or pre-profiled z. B. oval band with any number of adjacent oval cross sections connected by longitudinal ribs.
Minimization of the rolling work and roll stands. Achieve high productions at low outlet speeds due to the high number of round cross-sections connected and interconnected in the round belt. Straightening, slitting and cross cutting after reeling "in or offline". 4. Use of heavy bundles from round band z. B. in rebar mesh systems with straightening, slitting and cross-cutting systems prior to mesh welding. 5. Manufacture of round strip on today's hot strip lines as heat-treated coils.