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Test and Measurement Requirements in Metal Processing


The metal processing industry is one of the rapidly flourishing industries that contribute significantly to the growth of the Australian economy. For example, according to reports provided by the Australian Steel Institute, the steel industry generates $29 billion in annual revenue. The industry acts as a source of employment with over hundreds of local distributors and processing sites.

However, faced with the continuous demand and challenges of ensuring efficient production, manufacturers are now moving forward to implement automated test and measurement solutions to optimize the production process. Typically, processes involved in the metal processing industry, such as hot-rolling, casting and forming, require continuous monitoring and control of process-critical parameters. Measuring these parameters using automated measurement systems helps to detect faults in the process and prevent workplace safety hazards which are crucial for improving production efficiency.

Processing steel, aluminum, iron, and other metals demand an enormous amount of energy and harsh process conditions. This means any faults in the process can lead to wastage of energy as well as an increase in the cost-consumption. Therefore, the right measurement technology is required that measures process parameters under harsh and extreme environments.

Different parameters to be measured in Metal Processing:

As mentioned above, metal processing operations are sensitive to process parameters such as temperature, pressure, distance, and profile measurements. This is because all these parameters affect the production quality. Also, the physical properties acquired by the metal during processing play a vital role in ensuring that the final product later meets the desired specifications.

Temperature Measurement: 

The high-temperature operating conditions exist at various metal processing sites including, hot rolling mills, blast furnaces, induction hardening, and casting stages. To meet high-quality product requirements, the temperature throughout these processes must be maintained within the required range.

For example, the hot rolling process is carried out above the recrystallization temperature that is used to reheat shapes of metal to soften them enough so that they can be rolled further into rolling stands. Once the desired shape is obtained, the metal is cooled down to acquire desired mechanical properties. During the process, it is important to ensure that the temperature remains above the recrystallization temperature otherwise, the material must be reheated.

In such cases, non-contact infrared temperature sensors are used for metal temperature measurement from a safer distance from the object. Infrared pyrometers are well-suited for this purpose as they are capable of measuring accurately under harsh environmental conditions.

However, temperature monitoring applications in metal processing require different infrared measurement sensors to fulfill measurement needs. We have summarized information about various thermal imaging cameras and pyrometers that are currently used for monitoring and measurement purposes in the metal industry. Click here to read on.

Thickness Measurement:

The measurement of the thickness of the slab during the first rolling process is a crucial step involved in metal processing applications. Maintaining uniform slab thickness is vital to ensure high product quality and save production costs. However, high operating temperature, presence of steam, dust, and adverse conditions pose a challenge in choosing the right kind of sensing technology to obtain accurate measurement results.

To address this challenge, laser distance sensors are used for metal thickness measurement and can measure from a long distance to avoid any deviations or errors in the measured value. These sensors determine the slab thickness from the difference between the rolling mill and the slab on top.

Diameter Measurement:

The ring rolling process is one of the common processing applications used to seamlessly form stainless steel and titanium into large rings. The process takes place at temperatures of up to 1100 °C by placing a red-hot blank in the ring rolling mill. As the rolling process continues, the diameter of the ring increases. The diameter of the ring must be continuously monitored to avoid any failures at the processing sites.

Enabling precise measurements on red-hot glowing measuring objects, laser distance sensors are suitable for this measurement task. The sensor can be mounted at a safe distance of up to 10 m and measures the distance to the rolled material during rolling. The digital interfacing of the sensor allows transmitting the measured value to the production control system.

Read our application note to understand in detail how laser distance sensors are used for monitoring the diameter of  seamless rolled rings.

Pressure Measurement: 

Pressure is another important parameter that is to be measured during metal processing applications. For example, in the steel-making process, the first step is smelting which takes place in a blast furnace. Here, coke is used to provide necessary process heat, act as a metal reducing agent, and permeable support to the molten material in the furnace. To ensure high-quality coke quality is used, the pressure in each coke oven is individually monitored. This pressure monitoring is done with the help of pressure transmitters that can provide exact measurements in very small measuring ranges.

Profile Measurement:

When shaped steels are rolled in rolling mills in reversing operation, the hot-rolled bars are inspected for their dimensional accuracy for quality control purposes. The profile measurements are made to ensure that the geometries of the rolled products match the desired specification. Keeping in mind that the hot-rolled bars are glowing objects that emit the intrinsic radiations, conventional Red Laser sensors fail to measure reliably in such cases.

Here, Blue Laser sensors are used to measure the rod center at material speeds of up to 10 m/s. These sensors enable the measurement of the glowing target with a large measuring range to detect geometries of the rolled products.

Besides, there are other metal processing applications where using a blue lase sensor is preferred over a red laser sensor due to certain measurement conditions. The properties of the material to be measured, such as its reflectivity, shininess, and temperature, affects the decision of choosing a red and blue laser. Here’s an article to help you know what to consider when deciding between blue and red laser to make an informed choice.

Nevertheless, continuous measurement and monitoring of these parameters in metal processing applications are essential to ensure workplace safety, minimize site downtime, and maintain product quality standards. However, despite knowing the measurement requirements associated with these processing applications, it can still be quite overwhelming to choose suitable measurement technology that can provide accurate and reliable results.

To help you out, our engineers are here to guide you in choosing the appropriate measurement solution based on your requirements. Click here to contact us.

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