JPS611408A - Rolling processing method of billet having internal defect - Google Patents

Abstract

PURPOSE:To discriminate a defective bar stock in a cold shearing stage and to execute automatically sampling before it reaches a binding stage by tracking a billet extending from charging to a heating furnace to a rolling stage, and detecting and storing an internal defect by making it correspond to a position from the billet end. CONSTITUTION:A billet control computer 6 and a rolling control computer 7 are linked. In this state, a billet having an internal defect and a position of the defect are tracked extending from charging to a heating furnace 8, to a rolling mill group 9, by the computer 7. Subsequently, in the rolling stage, based on a difference of an elongation length by a product size, a position extending from the tip of a product to the defect is operated by the computer 7. In accordance with this information, when cutting the billet to a product size in a cold shearing machine 11 through a cooling bed 10, what order of product has an internal defect is discriminated from the tip of the product, and it is sampled by a sampling machine 12 before it reaches a binding bed 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for treating billets 1- and the like having internal defects such as inclusions.

[Prior art]

With the progress of continuous casting, inclusions that conventionally accumulated at the edges and center of steel ingots are almost uniformly dispersed in the slab, and inclusions, especially near the surface, are the cause of trouble after secondary processing. It becomes.

On the other hand, with recent advances in electronic technology, a technology has been established for ultrasonic flaw detection of the entire cross section of a steel billet, and steel billets with internal defects such as harmful inclusions can now be automatically identified. However, in order to meet the strict demands of customers, the proportion of steel billets with internal defects being rejected increases, which poses a major problem in terms of cost.

(Problem to be solved by the invention) That is, unlike surface defects such as surface flaws that can be removed, in the case of internal defects that cannot be removed, it is necessary to either reuse the entire steel billet or
This is because it must be rejected. As a way to avoid this, it is possible to roll the defective steel pieces together into steel bars, etc., and then re-select each product strip by ultrasonic testing. Since it becomes a product strip, productivity is extremely low and it is not practical.

Conventionally, to deal with such problems, for example,
As shown in No. 9184, there was a method of grasping quality information for each unit length of strip material. However, the above-mentioned prior art is limited to grasping quality information, and there is no description of its use, nor is it actually practiced.

The present invention was made in view of such problems, and includes:
The part with internal defects due to inclusions etc. is 0 of the billet length.
．． This was done by focusing on the fact that only about 0.1% of steel exists, and the purpose is to increase the effective utilization of steel slabs.

[Means 2 for solving the problem] In the present invention, internal defects in a steel billet are detected and stored in association with their position from the end of the steel billet, and the steel billet is tracked from charging into a heating furnace to the rolling process. ,
Product conditions with internal defects are identified during the cold shear process when the product is cut to length and removed prior to the bundling process.

Next, the present invention will be specifically explained.

FIG. 1 shows a block diagram of a device for detecting internal defects in a steel billet, and a device for storing defective portions in association with their positions from the ends of the steel billet.

Reference numeral 1 indicates an ultrasonic detection section, 2 indicates a defect determination section, and 3 indicates a defect position calculation section.

The steel piece a is conveyed in the longitudinal direction by conveyance rollers.

The ultrasonic detection unit 1 continuously inspects defects existing inside the steel piece a.

The ultrasonic detection unit 1 generates an analog signal depending on the degree of the defect. This analog signal is generated by a pulse oscillator 5 interlocked with the length measuring roller 4. In response to an interrupt signal generated by a pulse every time a unit length of the steel billet is fed, the defect determination section 2 performs A/D conversion each time, and determines whether or not the limit set value of a predetermined standard has been exceeded. , when the limit value is exceeded, that is, when the steel piece a is deemed to have a defect, a signal is output from the defect determination section 2 to the defect position calculation section 3.

In other words, the defect determination unit 2 classifies the ultrasonic inspection data corresponding to each unit length of the steel billet, compares this information with a predetermined quality control standard,
As a result, if it is determined that there is an abnormality, the defect position calculation unit 3
Outputs a signal to.

The defect position calculating section 3 calculates the position of the defect from the end of the steel piece based on the signal from the defect determining section 2 and the pulse count value from the pulse oscillator 5.

That is, the defect position calculation unit 3 detects that the ultrasonic detection unit 1
The pulses from the pulse oscillator 5 are counted from the moment the material is brought into contact with the material, and the position is calculated up to the time when the defect signal from the defect determining section 2 is input.

The calculated position of the defect is stored in the upper-level steel billet management computer 6, and the steel billet is tracked from charging into the heating furnace to rolling process and product sampling.

Figure 2 shows that the internal defects of the steel billet detected and stored in association with the position from the end of the steel billet are traced from the charging of the heating furnace to the rolling process, and the internal defects are traced when the steel billet is cut to length in the cold shearing process. FIG. 3 is a block diagram showing a process of removing defective product strips before reaching the binding machine.

The billet management computer 6 and the rolling management computer 7 are linked, and the rolling management computer 7 tracks the steel billet with internal defects and the location of the defect from charging into the heating furnace 8 to the rolling mill group 9. be done.

In the rolling process, the rolling computer 7 calculates the position from the top (tip) of the product to the defect based on the difference in elongation length depending on the size of the product. Based on this information, when the product is cut into an arbitrary length by the cold shearing machine 11 after passing through the cooling bed 10, it is possible to identify which product from the top of the product has an internal defect, and the cold shearing machine 11
From there to the bundling bed 13, it is extracted by a extractor 12.

The present invention is configured as described above, and even when rolling a steel bar and shearing it into multiple products, automatic sampling can be performed based on tracking information as to which products have internal defects. .

[Effects of the Invention] According to the present invention, steel billets with internal defects, which conventionally had to be diverted or discarded, or were rolled products and had to be sorted after re-inspection, can now be used until the product is bundled. This makes automatic identification and sampling possible, which is extremely effective in terms of cost and production.

[Brief explanation of the drawing]

FIG. 1 shows an outline of the configuration of an apparatus that implements one embodiment of the present invention.
FIG. 2 is a block diagram illustrating the relationship between a defect detection unit and shows a configuration in which a defective portion of a steel billet is stored in association with a position from the end of the steel billet. FIG. 2 is a block diagram illustrating the outline of the configuration of the apparatus and the process of tracing steel pieces with internal defects to products and rejecting them. 1: Ultrasonic detection unit 2: Defect determination unit 3: Large defect location calculation unit 4: Length measuring roller 5: Pulse generator 6: Slab management computer 7: Rolling management computer 8: Heating furnace 9: Rolling mill group 10: Cooling bed
11: Cold shearing machine 12: Sampling machine 13
: Binding floor diagram 1

Claims (1)

[Claims] Internal defects in a steel billet are detected and stored in association with their position from the end of the billet, and the billet is tracked from its charging into the heating furnace to the rolling process, and when it is cut to product length in the cold shearing process. A method for rolling a steel billet having internal defects, characterized in that product strips having internal defects are identified based on the stored information, and the product strips are extracted before a bundling process.