EP1222039B1 - Method for marking rolled material - Google Patents

Abstract

The invention relates to a method for marking material defects in/on bar-shaped rolled material after it has left the finishing rolling mill. According to this method, the defective points are detected during the rolling process by ultrasound testing and/or inductive testing and this information is supplied to a computer, which identifies and stores the defective points according to their type and position in the rolled product. The computer then uses this data to control a marking device in such a way that the bar-shaped finished material is marked according to the defect type, respectively, at the point determined by the computer.

Description

The invention relates to a method for marking in / on Rod-shaped rolling stock detected material defects according to the preamble of claim 1 (see e.g. DE-A-4 217 007).

As a rule, already rolled steel products are under With the help of suitable test devices on interior and External defects examined.

For the detection of internal defects, i.a. ultrasonic probes used for the detection of surface defects, for example Continuous coils or eddy current probes rotating around the roll core.

The identified errors are on the product, for example a round bar, according to its type over the entire circumference or only marked locally. Surface defects do not always result to reject the bars as they can be repairable. internal error cannot be repaired. The faulty piece must be cut out.

As a rule, internal defects already occur when pouring or in the cooled steel block, from which the bars are then rolled should.

The further such a block is rolled out - in the end to the rod-shaped end product - the more difficult they are existing internal defects can be detected. So it happens that there are defects in the finished product in the starting product can no longer be recognized.

In the described method, the error check and the So only mark one if the one used for the order Material is rolled out. Each rod must (usually after cutting to customer length) in a separate operation be checked.

The invention has for its object a method of type mentioned so that the errors as possible are recognized early on during the rolling process and the marking on both the hot and the cooled Material before further work steps such as e.g. the judging can take place and thus the period between Rolling, checking and sorting out the faulty bars minimized becomes. This may be between the internal exam and forming steps or cooling sections in the external inspection considered accordingly.

The invention solves this problem by a method in which by means of ultrasonic testing and / or inductive testing Defects are detected during the rolling process, these Information sent to a computer and used by it in accordance with Art and position in the rolled product are identified and stored and the computer uses this data as a marking device controls such that the rod-shaped finished material according to the type of error on the computer Location is marked.

An essential aspect in the present invention is therefore seen in the fact that the errors even before Finished rollers can be tracked down in one place which the starting product has not yet been rolled out so far that the existing errors could be "overlooked", the recognized ones Errors nevertheless by type and position in the finished part directly after the rolling process or after cutting on cooling bed or customer length on the finished part are marked so that the faulty ones are based on these markings Products according to the type of defect in "good", "repairable" or "scrap" can be sorted.

This is done using electronic data processing after reporting an error, recognizes the type and location of the error calculated in the later end product and with this data the Marking device controls. Here, "marking" means primarily a color marking from the end product. The marking can be used for interior and exterior faults or reparable and irreparable errors occur with different colors.

According to the invention, however, it can also mean that it is is an electronic virtual "marking", based on which the sorting process is controlled, the computer is connected to the sorting device.

The fact that error detection and marking in the rolling and Cutting process are integrated, this results in a more precise and prior accurate error detection and minimization the process time. The bars recognized as well can therefore be used directly for straightening or deburring.

Since experience has shown that there are many in the head of the rolled material If there are errors, the error detection according to claim 2 is only started with a time delay, depending on from the final roll speed (3 m / sec to 15 m / sec), so that the head piece to be skimmed anyway in the detection and thus is not taken into account when marking.

According to claim 3 it is provided that the detected individual errors summed up during a preset period and the marking command only when a defined error relevance level is triggered.

This can ensure that not everyone is small Error immediately leads to a marking command, but only the product is actually unusable or used Post-processing leading errors are marked.

The marking of the determined relevant errors can be according to claim 4 directly on the hot rolled material shortly after leaving of the last roll stand, i.e. before cutting to the length of the cooling bed respectively.

With the help of the existing EDP, the marking can also be done after Cooling down on the cooling bed before or after cutting to customer length be performed. This requires a logical marking done by the program in the computer so that the faulty Part of the roll vein virtually marked and sorted out can be.

Here, the program of the computer can determine how the Cooling bed lengths optimally used for allocation to customer lengths become.

The customer lengths (for example 6 m) are always certain Tolerances possible or specified.

For example, in a cooling bed length is a 35 m long one flawless piece in front, do not need slavishly five 6 m long Customer lengths to be cut so that a 5 meter long unusable piece remains. The tolerances are exploited that here, for example, the 35 m in six lengths each 5.83 to be divided.

This method according to the invention possibly in conjunction with an automatic rejection device leads to a high Rationalization effect, which on the one hand costs and on the other the time involved.

Claims (6)

1. A process for marking material defects in or on rod-shaped rolled stock after it leaves the finishing roll stand, in which ultrasound testing and/or inductive testing are used to detect the defective places, this information is fed to a computer and the latter identifies and stores it in dependence on the type and position in the rolled product and the computer uses this data to control a marking device such that after it leaves the finishing roll stand the rod-shaped finished material is marked in accordance with the respective type of defect at the location determined by the computer, characterised in that the defective places are detected during the rolling procedure and the computer calculates the location of the defect in the later end product.
2. A process according to Claim 1, characterised in that the defect evaluation or defect detection and the marking command are only performed after a pre-set period of time after the start of material testing which is dependent on the final rolling speed.
3. A process according to Claim 2, characterised in that the individual defects detected during a pre-set period of time are added up and the marking command is only triggered when a defined relevance level for defects is reached.
4. A process according to one of Claims 1 to 3, characterised in that the marking is performed directly onto the hot rolled stock before it is cut to cooling bed lengths.
5. A process according to one of Claims 1 to 3, characterised in that the marking is performed after cutting to cooling bed length and before or after cutting to the length specified by the customer.
6. A process according to one of Claims 1 to 3, characterised in that the marking is a purely virtual marking performed and stored by the computer program.