Improved Process Monitoring & Greater Efficiency In Steel Production Processes

Today’s increasing quality standards and higher energy costs demand more accurate and consistent temperature control in the steel making process. Processes such as coke oven heating, continuous casting, furnace reheating, hot rolling, and forging are becoming more and more expensive. Steel facilities need the right tools to ensure they optimize energy usage across their facilities.

With over 30 years of experience providing efficiencies through light-based measurement, Dpstar is an industry leader in process monitoring and delivers innovative temperature measurement instruments for all areas of steel manufacturing. Our infrared measurement technology provides the steel industry with cutting-edge technology, ease-of-use, and dependability for monitoring critical parameters for productivity and product quality. These solutions are used throughout the steel manufacturing process, where accurate temperature monitoring is required for improved control. Dpstar addresses these needs by providing the most accurate measurements in the industry, enabling steel facilities to maximize their output. Dpstar noncontact infrared thermometers are designed for use in steel manufacturing processes where monitoring and controlling temperature is critical to productivity and product quality. Temperature readings show whether processes are operating within their proper ranges, whether a reheater is too cold or too hot, whether a stand needs adjusting, or how much cooling should be applied. Each stage can be accurately monitored so the steel retains correct metallurgical properties as it travels through the milling process. Every section of the steel manufacturing process can benefit from Dpstar infrared thermometers. These benefits include:

• Higher quality products
• Increased productivity
• Reduced energy costs
• Enhanced worker safety
• Reduced downtime
• Easy data recording

Our infrared sensors take temperature measurement one step further. Simultaneous analog and digital output allows temperature data to be integrated into a closed-loop control system and simultaneously output for remote temperature monitoring and analysis. Our sensors, with digital electronics and 2-way communications, can be configured remotely from the safety of the control room. The result: increased functionality and greater control. A wide range of optics, including a remote-controlled, motorized variable focus, covers an enormous variety of applications. This is supported by integrated through-the-lens sighting, plus either laser or video sighting for correct target location.

Major Applications 

Continuous Casters

Melters can be either cross-fired (as shown in Figure 1) or end-fired. Regenerators improve fuel efficiency by heating incoming air and alternating the firing direction. The temperature of the brick packing in the regenerator columns increases as the heated air from the furnace escapes. When this packing reaches the appropriate temperature, the cycle is reversed and these columns are then used to heat air entering the furnace. To ensure maximum operating efficiency, Raytek sensors are mounted at the top and bottom of each regenerator to trigger the air flow and firing direction at the optimum time. Using Raytek sensors to monitor the packing and refractory material for deterioration is crucial in planning the maintenance and rebuilding schedules, and eliminating emergency situations which could cause a costly, unscheduled shut down. The temperatures at the port arch and the bridgewall are measured to maximize the useful life of the refractory material. The precise aiming capability of Raytek sensors allows measurement of individual target bricks and avoidance of the furnace flame. 

Reheating Process  

Reheating steel to a uniform temperature is critical so deformation does not occur. Uneven heating strains milling equipment and increases maintenance downtime. Measuring the inside of a reheater with a series of temperature measurement devices (as shown in the Reheating Interior illustration) gives an operator the ability to check the reheater’s overall temperature and burner efficiency. The ability to correct the reheating process results in more efficient use of fuel, which in turn produces a better quality product with less environmental waste.

Once the slab or billet exits the reheat furnace (Reheating Furnace illustration), Marathon infrared ratio thermometers or MP150 linescanners (for wide slabs) transmit temperature data immediately to an operator or controller allowing milling operations to be adjusted to their correct settings.

Hot Rolling Mills   

The diversity in the types of hot rolling mills and the number and types of stands in a process vary according to the type of product being manufactured (refer to the Hot Rolling Mill illustration above). In all aspects of the steel manufacturing process, ongoing temperature measurements and stand adjustments ensure that quality and process line uptime is the norm and not the exception.

Scale Breaker
Marathon MR high performance ratio thermometers or a 1-micron MP150 linescanner (for wide slabs) placed before the scale breaker and before the roughing stands allows the operator to check that product temperatures are within rolling limits and to set the roughing mills accordingly.

Rolling Stands
Cooling continues as the steel makes its way to the rolling stands. If a process line stops for any length of time, the steel may cool more than usual before starting up again. Either way, the stands’ rolls must be set to compensate for the temperature change. Rolls can be set manually by an operator, or Raytek infrared sensors mounted before each stand can automatically set the milling equipment. This makes sure the stands are configured properly for the steel’s temperature. For controlled cooling areas, where steam and dust can block temperature readings, a Marathon MR ratio thermometer takes accurate measurements with up to 95% of the target obscured.

Down Coiler
At a hot rolling mill (similar to the illustration above) cooled steel is often rolled at the down coiler for transport to a cold mill or to another facility. Accurate temperature measurements at the down coiler are needed to maintain proper cooling at the laminar-flow cooling section. Temperatures at this point are critical as incorrect cooling can change metallurgical properties and the coil would have to be scraped.

Coil Box
Because the cooler steel at this point may be traveling 22 to 30 meters (75 to 100 feet) per second, a low-temperature infrared sensor with a fast response time, such as the Marathon MM, is needed. Another type of coiling is done at some mills where hot steel is coiled after the roughing stands for transport to another plant location. The hot rolls are then uncoiled and run through the finishing stands, cooled, then recoiled at the down coiler. Where the hot roll is uncoiled, accurate temperature measurement and monitoring are important so the operator can correctly configure the finishing stands’ rollers.

Cold Mills    

Coiling is also often done at the end of the finishing stands after cooling, and the coiled steel is transported to cold mills in another area in the plant or shipped to other facilities. Cold rolling makes a product thinner and smoother and is done while the steel is around 100°C (212°F). Sensors mounted between each finishing stand allow the operator to detect temperature changes that require any adjustments.

Rod/Wire Mills     

Other high-speed processes include rod and wire mills. In a typical rod or wire mill, billets are reheated and sent through a rolling mill to be reshaped as rods (refer to the Rod/Wire Mill illustration on the following page). From here, the rods go through a series of intermediate stands that reduce the rods to different sizes. Finishing stands reduce and smooth the rods into a product that can be further processed into hundreds of different products. Reheating a billet to a uniform temperature is critical to the entire process. Uneven heating strains milling equipment and increases maintenance downtime. Knowing the temperature of the product at each stand allows the operator to adjust the rollers accordingly. When the product heads for the cooling area, cooling is rapid but carefully monitored to make sure the metallurgical properties are correct. If cooling is improperly controlled, the product would not meet specifications and could be downgraded or scrapped. In some processes, the high speed and vibration of the narrow rod or wire products make temperature measurement difficult. Marathon high-performance infrared ratio thermometers solve this problem. The target can drift in and out of the field-of-view or be partially obscured by dust, steam, and obstacles, and the Marathon sensor will still take accurate temperature measurements.

Other Processes   

Dpstar has temperature measurement solutions for every step in the steel-making process, from coke ovens and blast furnaces to annealing mills and coating mills. Dpstar also has temperature measurement solutions for forging mills and heat treating facilities. Wherever temperature is a factor in production, from the raw material to the finished goods, Dpstar is there to help. Our applications specialists are located around the world to help answer your technical questions.

Products for the Steel Industry 

Marathon Series combines superior performance with state-of-the-art digital technology and is a family of unique infrared instruments designed for operating in harsh environments. These integrated units offer advanced electro-optics, smart digital electronics, and built-in user interface in a rugged, compact housing. Included in the Series are the following:

• One and two-color infrared thermometers
• Short wavelength/low-temperature thermometers
• Fiber-optic infrared thermometers
• ThermoJacket and accessories
• Field calibration and utilities software
• Configuration and monitoring software

DataTemp Multidrop Software
Windows software for Marathon thermometers feature trend plotting, data logging, sensor setup, process alarming and statistical process control.

MP150 Linescanner
This product offers a cost-effective way to measure edge-to-edge temperatures for control of product uniformity, providing data for a 90º field-of-view.

DataTemp DP Software
Windows software for the MP150 linescanner allows remote temperature monitoring, control and analysis. Thermal images can be viewed in real-time or saved and process irregulations corrected before they become problems.

Advice tailored to your needs

With our comprehensive experience in the steel industry, we can deliver top-quality engineered solutions for every stage of your steel manufacturing.

Dpstar Group
No 35, Jalan OP ½, Pusat Perdagangan One Puchong,
Off Jalan Puchong, 47160 Puchong,
Selangor Darul Ehsan, Malaysia.
Email: [email protected]