Optimise your line!

The latest generation of advanced high strength steels (AHSS) involves sophisticated heat treatments, including austenitization and ultra-fast cooling of the strip within the furnace.

Drever International proposes the X-CAP® (X-ray Controlled Annealing Process) technology that allows the measurement of the steel austenite content within the furnace. With the X-CAP®, an innovative solution has been developed to improve the control of the complex manufacturing process of AHSS production.

Why do you need X-CAP®?

X-CAP® technology to measure austenite content of the steel within the furnace. The sensor is supplied by IMS Messsystem?

The production of modern AHSS (Advanced High Strength Steel) grades places high demands on the thermal process in annealing and hot-dip galvanizing lines. In particular, the automotive industry requires homogeneous properties of the steel strips not only over the entire length of the coils, but also from coil to coil. In order to achieve this, an on-line information on the steel structure is necessary to control the process and compensate possible deviations caused in the upstream processes.

Coil samples for quality measurement are taken at the end of production lines. Online quality measurement can be implemented on a heat treatment line, but in friendly environment, far after the annealing process. At that point the material already has its final mechanical properties and a closed-loop control of the process is no more possible. A breakthrough measurement system including a control model has been developed, the X-CAP (X-ray Controlled Annealing Process) by SMS group, Drever International and IMS Messsysteme. The X-CAP measures the steel structure on-line and within the annealing process, inside the furnace. This allows to control the mechanical properties in the very process step where they are finalized.

Finished AHSS grades consist of a combination of two or more phases to achieve the required material properties. During the heat treatment, the fraction of austenite before rapid cooling determines the amount of the secondary hard phases formed in the subsequent cooling stages. For AHSS, the secondary phase fraction is the main influence on the strength of the final product. With X-CAP, a system is now available for the real-time quantification of the austenite content during the annealing process.

The new online measuring system uses X-ray diffraction to define the crystalline phase fraction, and hence the austenite content, upstream of the furnace rapid cooling section. The continuous measurement of the austenite content in the furnace allows to directly compensate process and material changes, which otherwise would lead to product quality deviations.

The X-CAP hardware is installed inside a specially developed protective housing, designed to be implemented in any furnace. The first device was successfully implemented in 2017 inside of the furnace of one of our Partners in Belgium. The measurement results were first compared to the final product strength. Then the X-CAP control was released and significantly improved material quality. X-CAP can save coils and keep the characteristic material properties within the required range. The X-CAP control is designed to cope with transition management of various steel grades, which even experienced operators are unable to achieve.

Producers of annealed and galvanized cold rolled steel strips are facing several challenges when it comes to modern AHSS grades. With the X-CAP an innovative solution has been developed to significantly improve the complex process of AHSS production.