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Category Archives: Oscillation Monitor

Frequency of the Oscillation Table: Cracks, bleeding, and breakouts can be associated with it?

Irregular frequency of the oscillation table generated by a failure in the liquid steel leveling sensor causes a great loss to production, quality, and maintenance.

Steelmakers observed that product downgrading in steel mills can be associated with problems with the oscillation table in continuous casting machines.

As reported by a customer, the maintenance team was dealing with excessive machine’s downtime.

Continuous breakout incidents or other problems related to the oscillation table and the mold, which in turn also concurred with decreasing in product’s quality, which came to show cracks and lapses regularly.

Discarted moulds showing damage caused by breakouts.
Picture 1: The picture shows the consequences of breakouts.

Discarted moulds showing damage caused by breakouts.
Picture 2: The picture shows cracks on both billet and bloom.

In order to investigate and solve the problems at the company, the customer contacted Tozato.

At the company’s request, Tozato’s engineering team traveled to the company to provide support and investigate the issue using a tri-axial sensor equipment, which analyzed the trajectory, vibration, and metallurgical conditions of the mold’s oscillator.

Frequency of the Oscillation Table’s problem detection and analysis

The problem was discovered after measuring the oscillation table with Tozato Measurements’ cutting-edge technology equipment. It was found that the oscillation table’s frequency was undergoing major changes (from 81 CPM to 116 CPM) in a matter of a few seconds.

This acceleration and abrupt reduction of frequency not only caused extra wear in the copper molds, but also resulted in constant breakouts in addition to causing product downgrading, forming severe cracks and recurring bleedings.

Discarted moulds showing damage caused by breakouts.
Picture 3: The picture shows irregular peaks of frequency of the oscillation table on the trend line.

The suspicion was that the high and rapid changes in the oscillator’s frequency were caused by the lack of calibration of the leveling sensor that assists in the distribution and volume of liquid steel within the copper mold.

Since it was without proper calibration, the motor was activated at the driver’s command to sometimes compensate the frequency, sometimes to reduce it.

Discarted moulds showing damage caused by breakouts.
Picture 4: The picture shows, in the short period of exactly 14 minutes and 56 seconds, a variation of 81.37 CPM minimum and 116.5 CPM maximum.

It is common knowledge that the continuous casting machine operates from the motorized impulses which in turn assist the oscillation table and, at a steady frequency, provide high product quality. However, when there is a problem with the leveling sensor’s calibration, this frequency can change and cause major problems in the production and quality areas, as it was in this case with this customer.

Immediate solutions were provided by Tozato’s engineering team. After identifying the problem and confirming the diagnosis using the monitoring system, the company requested the installment of Tozato’s continuous monitoring equipment to control the mold’s oscillation table.


As a consequence of Tozato’s high precision and resolution equipment, the company was able to increase the production, so that the quality of these products was within the required standards, avoiding greater expenditures with maintenance and product’s downgrading, since the use of this system increased the mold’s and the oscillation table’s service life, acting against rhomboidity and ovality, in addition to proving to be efficient in drastically reducing the incidence of breakouts.

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Production errors anticipating through monitoring

How many production errors and issues could be avoided through constant monitoring of oscillators?

Many accidents signalize their occurrence long before they happen and, most importantly, it is possible to prevent if you have the right tools at your disposal. Thus, the monitoring of mould oscillation is a determining factor for accident prevention and production errors that can cause damages and losses to the process.

Aware of that, a customer of Tozato Measurements installed an online system for monitoring the oscillation of the mould, looking to have total control of its process and anticipate errors that could cause losses and many headaches.

A right decision made.

Preventing production errors

With the installation of equipment capable of permanently monitoring the condition of oscillators, operators have at their disposal a wide variety of fundamental information. Through the use of high precision and speed tri-axial accelerometer sensors, data collection is able to monitor the trajectory, vibration and metallurgical parameters of the continuous casting process.

Using the TOM data, the customer found that the oscillator’s vertical velocity waveform began to show an irregular pattern, which indicated that the continuous casting machine was not operating in its full state of efficiency.

Oscillation curve with an irregular pattern, indicating production errors.

After finding the cause of the problem, the machine’s eccentrics were changed and the waveform immediately returned to a clear sinusoidal pattern.

Oscillation curve with a regular pattern, indicating a CCM free of production errors.

“Had the problem not been anticipated, it would have been much worse. This maintenance, pointed out by the system, helped us to avoid an unexpected outage of more than 10 hours. So, we managed to keep the schedule and avoid a lot of headaches and annoyances”.

Breakout prevention

Evidently, that was not the first time that the relationship between the monitoring of oscillation and the reduction of accidents and production errors could be seen.

Another time, other customer had already pointed out the installation of the mould monitoring system as a determining factor for the reduction of almost 70% in the annual incidence of breakouts.

CCM Break-Out down rate over the years

Online monitoring benefits

The mould oscillation monitoring systems are applied to monitor the real time conditions of the mould oscillators of continuous casting machines in order to verify vibration, trajectory and metallurgical parameters of the steel casting process.

Mould oscillation monitoring is carried out aiming to achieving the following purposes:

  • Evaluate the mechanical conditions of the oscillator;
  • Monitor the steel continuous casting process;
  • Monitor the characteristics that influence the product surface quality;
  • Create a history of oscillator wear trends;
  • Reduce preventive maintenance downtime;
  • Optimize time and resources;
  • Increase the service life of oscillators and copper moulds.


Unquestionable results such as this can be achieved thanks to the intelligent application of resources. Through consistent application of oscillation monitoring, it is possible to achieve results that benefit both the production and maintenance sectors.

Therefore, more and more steelmakers around the world are engaging in control to achieve their goals.

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Friction and its Relation with Internal Mold Condition

There is a relation between the mold internal condition and the oscillation friction during the continuous casting process. This relation, however, was only proved after applying both Mold Oscillation Monitoring and Mold Profile Checker simultaneously. Check out the results down below.

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LVDT and its readings on hydraulic continuous casting machines

A usual mistake made by companies that work with hydraulic continuous casting is to assume that the LVDT (linear voltage displacement transducer) is able to provide reliable information regarding the oscillation performance. However, the LVDT does not provide any kind of information directly on the oscillation table itself. It only is capable to give information about the hydraulic cylinder performance

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Mold’s early wear and the influence in steel surface defect results

The continuous casting machines’ oscillator may suffer interferences from many factors, therefore, leading to mold’s early wear. The relation between it and steel surface defects is huge, but when the root causes are properly handled, the problems is solved.

Tozato Measurements team performed a consultancy service at a customer that was experiencing a high rate of product downgrading. That being the case, it was noticed that the strands were presenting severe early wear problems in their molds as a result of frontal and lateral displacement errors.

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Early wear and friction on continuous casting copper molds

The high friction level in continuous casting machine’s mold tubes strongly reduces their service life. A relation that can be proved by using appropriate tools to collect and analyze data.

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Oscillator topographic unleveling and mold service life time

It is rather common to have the copper molds with decreased service life due to early wear. The improper wear, among other reasons, is caused by intense friction between the product and the mold, therefore, resulting in trajectory errors offset caused by an oscillation table topographic unleveling.

After all, is there a straight relation between the oscillation table topographic leveling and the coper molds early wear? The study below will help you to understand how much these two factors are related.

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Trajectory errors and mold wear: the correlation between these factors

During the continuous casting process, many factors may cause surface defects. However, two of them are very common and need special attention: oscillator’s trajectory errors and mold wear.

Nonetheless, it was not always possible to verify and prove the correlation between those two factors. With the advance of technology in oscillation monitoring, and in mold internal faces’ measurements, it was possible to prove this relation successfully. Find out more:

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