JPS6174707A - Clamping equipment - Google Patents

Abstract

PURPOSE:To prevent a clamping part of bar from local overcooling and to eliminate the temperature difference in the material by heat-insulating a clamped bar with the aid of a heat source incorporated in each clamping part, in case of clamping a preceding bar and a succeeding one respectively to join them together by welding. CONSTITUTION:The rear end of a preceding bar 1 and the front end of a succeeding bar 2 are clamped by the clamping parts 6 of clamping devices 4, 5 respectively on the upstream of a finishing mill line, to form a joining line 3 for butt welding. In this state, the bars 1, 2 are joined to each other on the joining line 3 and connected together by welding. Each clamping part 6 consists of heat resisting material, and a heat source 7 is incorporated in it. Heat is supplied from the source 7 when a high temperature material is clamped, to heat the contact surface of clamped material. In this way, the local overcooling of material is prevented, and the temperature difference in the inside of material is decreased, to homogenize a product by preventing or relaxing the generation of defects.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a clamping device for a hot zone four-continuous rolling mill that can be applied to a hot material joining device.

(Prior art) In conventional hot trip mills, slabs have been rolled into product strips. In other words, the slabs exiting the heating furnace are rolled into rough bars of intermediate thickness in a row of rough rolling mills, and then rolled into rough bars of intermediate thickness. It is rolled into a strip of product thickness in a finishing mill row, cooled to the required temperature while running on a runout table exceeding 1QQm, reaches a coiler, and is wound up as a hot-rolled coil. BACKGROUND ART In recent years, advances in rolling technology have made it possible to reduce product costs by adopting hot-rolled sheets in fields where expensive cold-rolled sheets were used, and the demand for hot-rolled sheets has been increasing year by year.

In order to efficiently produce hot-rolled thin sheets, it is necessary to prevent the tip of the strip from flying out of the finishing mill.
The threading speed can be increased until the tip of the strip reaches the coiler and is wound onto the coiler mandrel, but since the tip of the strip runs on the runout table without restraint, the speed is particularly high on slopes with thin gauges. Threading was difficult and it was not possible to roll efficiently.

In order to resolve this difficulty in threading the tip of the strip and roll it efficiently, the rear end of the leading bar and the tip of the trailing bar are joined and rolled upstream of the finishing rolling mill row, near the upstream side of the coiler. There is a so-called continuous rolling method in which the material is divided into two parts. Furthermore, in order to butt weld the rough bars after rough rolling, a clamping device is required to position the end faces of each bar, fix them to each other, and connect the joining line.

Because there is a large temperature difference between this clamping device and the bar to be joined, the clamped part of the bar is locally supercooled.
This increases the deformation resistance, and during rolling into strips in the finishing mill row, the plate thickness becomes thicker in this area, resulting in off-gauge, which deteriorates the product yield.

(Problems to be Solved by the Invention) The present invention solves the conventional problems such as reduction in rolling efficiency and deterioration in product yield. It prevents overcooling and reduces the temperature difference distributed within the material, and prevents or reduces the degree of defects caused by temperature differences in subsequent processes, homogenizes the product, and improves yield. It is an object of the present invention to provide such a clamp device.

(Means for Solving the Problem) Therefore, the present invention provides hot rolling for the trailing end of the leading bar during finish rolling upstream of the finishing mill row and the leading end of the trailing bar after rolling in the rough mill row. This is a clamping device for a continuous hot strip rolling mill that welds and joins steel strips for continuous rolling, and has a configuration in which a heating means is built into the clamping device.

(Function) Now, in the above configuration, the rear end portion of the leading bar and the tip end portion of the trailing bar are clamped by respective clamping devices so as to form a joining line. In this state, the bars are welded and connected at the joining line, and after the joining is completed, the clamping device is released and the leading and trailing bars are continuously sent to the finishing mill row without interruption. Since the temperature difference between the bar to be joined and the park clamp part of the clamping device is large, the clamped bar part is locally cooled. The present invention uses a heating means built into the clamping device to heat and keep the clamped material portion warm to prevent local overcooling.
Temperature differences that occur in materials can be reduced.

(Example) Below, the embodiment I-t-drawings of the present invention will be explained.
1 and 2 show embodiments of the present invention. Now, here we will discuss hot rolled strip steel in a hot strip mill, especially continuous rolling of hot strip steel to efficiently produce thin gauge products, that is, upstream of the finishing rolling mill row, and the trailing end of the leading bar 1 during finishing rolling. The tips of the trailing bar 2 after being rolled in the rough mill row are hot welded and rolled as a continuous bar into strips in a finishing mill, cooled on a run-out table, and wound up in a coiler. In the upstream process of rolling to divide into coils of the required size, high-temperature bars are butt-jointed, so the rear end and tip of each bar are positioned, and the bars are placed against each other to prevent the joining line from shifting during the joining process. The clamp device for fixing will be explained.

Now, in FIG. 1, the rear end of the leading bar 1 and the leading end of the trailing bar 2 are clamped by respective clamping devices 4 and 5.
The respective end faces are positioned for butt jointing and are clamped by upper and lower material clamping parts 6 with a bar between them so as to form a joint line 3. In this state, the bars 1.2 are welded and connected at the joining line 3, and after the joining is completed, the clamp device 4.5 is released, and the leading bar 1 and the trailing bar 2 are welded together.
The rolling stock is continuously sent to the finishing mill row indicated by arrow Z without any interruption.

Since there is a large temperature difference between the temperature of the bar to be joined (900 to 100° C.) and the park clamp portion of the clamp devices 4 and 5, the clamped portion of the bar is locally cooled. The deformation resistance of hot steel increases as the temperature decreases, so when locally cooled parts of the material are rolled in a finishing mill, the rolling rolls are rolled as if they were rolling a skinned part. It varies by widening the gap and increasing the plate thickness.

AGC (automatic plate thickness control) in the finishing mill performs correction control to compensate for plate thickness fluctuations, but local temperature changes are localized and sudden compared to the 7) marks, so corrections are necessary. This part becomes off-gauge. Particularly in thin gauge rolling, the rolling elongation rate in the finish rolling mill row is large, so for example, if the Franz width at a fixed point with an elongation rate of 20.11 is 100, the product strip rolled in the finishing pressure 11 row will be Approximately 2000m of each of the 11 locations will be off-gauge.

FIG. 2 is a conceptual diagram for explaining the present invention in detail,
An overview of the material clamping part of the clamping device is shown. The material clamping section 6 is made of a heat-resistant material, and is provided with a heat source 7 that heats the clamping material contact surface.

When clamping a high temperature material, a large amount of heat is supplied from the heat source 7. The heat source may be an electric heating method, gas combustion method, powder heating element combustion method, steam, infrared rays, etc., and should be selected as appropriate depending on the material and its temperature.The heating method should be strong when clamping the material, and weak heating when releasing it to keep it warm. Alternatively, heating may be stopped.

By attaching a heat source to the clamping device and supplying 2Bq to that part when clamping the material, it is possible to heat and keep the clamped material part warm, prevent local supercooling, and reduce the temperature difference that occurs in the material. .

Therefore, due to the temperature difference distributed within the material, defects such as gauge fluctuations and partial deterioration that may occur in subsequent processes can be prevented or reduced, and product yields can be expected to improve. .

Figure 3 shows the 5OL (thickness) sheet bar (Sheet B
ar) shows changes over time in the surface temperature and average temperature of ceramics and heat-resistant steel without preheating and with preheating. Also, as can be seen from Fig. 3, the temperature drop has been drastically changed.

(Effects of the Invention) Since the present invention is configured as explained in detail above,
When joining high-temperature materials, it is possible to prevent local overcooling of the materials due to contact with the clamping device, reduce the 'lAa degree difference distributed within the materials, and prevent defects caused by temperature differences in the subsequent process, or We aim to reduce the severity of the problem and make the product more homogeneous.
Yield can be improved.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view of a clamp device showing an embodiment of the present invention, FIG. 2 is a detailed cross-sectional view of the same essential parts, and FIG. 3 is an explanatory diagram showing changes over time of a 50t sheet bar. Description of the main parts of the diagram

Claims (1)

[Claims] Continuous rolling of hot strip steel by hot welding the rear end of the leading bar undergoing finish rolling upstream of the finishing mill row and the tip of the trailing bar after rolling in the rough mill row for continuous rolling. A clamp device for a machine, characterized in that a heating means is built into the clamp device.