Sias automated surface inspection for flat products

Light bar and camera of a SIAS installation for one side of the strip.

Producers of flat-rolled steel are facing a growing trend toward zero-defect tolerances for surface quality. This trend, initiated by customers in the automotive industry, is increasingly becoming the norm in other sectors—namely in packaging, “white goods” (appliances), and others. From a quality management (ISO) perspective, it is necessary to standardize surface quality like any other product characteristic.

The Automatic Surface-Inspection System (SIAS) from Primetals Technologies is an online surface­-quality control solution that helps address this challenge by detecting and automatically classifying all surface defects visible on the strip: inclusions, mechanical damage, scales, repeating defects such as roll marks and dents, as well as coating defects and other imperfections.

The system uses high-end cameras, optics, and lighting to provide a sharp, fine-resolution image of the strip surface. Recent developments in the next-generation platform include high-resolution and near-infrared vision techniques. The obtained image data is software-processed for defect identification: flaws are detected, automatically classified, and graded for severity. The results are displayed to the operator, and stored in the form of coil reports mapping the defects on every coil. They comprise defect data (size, position, type, and severity), defect images, and context information such as mill/line speed and product texture. All information is stored in an open and SQL-compatible database structure, which allows for easy compilation into studies at a later stage e.g., to determine trends on groups of coils by grades or by dates.

The results are also available to the operator in real time, allowing immediate reaction. Through the SIAS coil-grading software, the quality department can determine instantly whether the coil surface quality matches the requirements of the customer—and what action to take if this is not the case.

SIAS is available for all flat-product rolling and processing applications: hot mills, pickling lines, cold mills, continuous annealing lines, metallic coating lines, hot-dip galvanizing lines, electrolytic galvanizing and tinning lines, color-coating lines, and stainless steel lines.

In recent times, advances in digitalization have made it possible to perform analyses remotely and help customers more quickly whenever support is required. Remote-­access services for SIAS, as offered by Primetals Technologies in combination with a customer-support hotline, have the advantage of including prompt hardware diagnosis, providing support over a longer time span, and facilitating remote defect-detection analysis.