Thicker 6xxx plates

For many years, AMAG has been among the leading specialty suppliers of high quality aluminium flat products and is known for reliably producing demanding product dimensions and qualities on an industrial scale. When AMAG built its new hot rolling mill and plate production facilities as part of the large scale “AMAG 2014” project, the entire plant and process design was initially based on a maximum plate thickness of 6 inches. This reflected the common market requirements at the time and marked an important technological step: The new hot rolling mill became one of the largest investments in the European aluminium industry and, featuring modern rolling stands, new heat treatment furnaces, integrated plate production, and precisely aligned material flows, offered maximum flexibility and productivity.But the market continues to evolve. Especially in the semiconductor and mechanical engineering sectors, the demand for thicker plates increased.AMAG’s ambition to consistently offer its customers solutions beyond standard specifications is the driving force behind the continuous optimization of our product portfolio and the ongoing development of our manufacturing technologies. The decision to increase the maximum plate thickness from 6 to 7 inches (152.4 to 177.8 mm) is a strategically important step to unlock new applications, expand technical degrees of freedom, and further strengthen our position in demanding high performance segments enabling us to meet future customer requirements even more comprehensively.

6-7: Extending the operating limits

In order to integrate this new product dimension safely, in accordance with quality standards, and within the existing process chain, a number of changes and tests are required. Extending from 6 to 7 inches is by no means a trivial “increase in material.” Technically, it is closely linked to the entire process chain: From casting technology to hot rolling, heat treatment, and inspection, forces, temperatures, cooling rates, rolling passes, and equipment capacities must be reconsidered.Increasing the thickness to 7 inches results in higher masses, forces, and inertias along the entire production route. This affects rolling forces, sawing forces, heating and cooling behavior, as well as handling and crane loads. At the same time, the required shape, thickness, and surface tolerances must continue to be maintained.The equipment must first be assessed to determine whether it can safely handle the higher forces, loads, and geometries. This includes checking geometric constraints (pass through heights) and evaluating mechanical, control, and safety related performance limits. Identified bottlenecks form the basis for necessary technical modifications. Implementation includes mechanical adaptations to stands, guides, clamping and transport systems, as well as adjustments to drives, brakes, and control technology. Thermal equipment must also be reviewed and, if necessary, adapted with regard to load capacity and temperature homogeneity. The goal is a stable, safe, and reproducible production process for 7-inch plates.

Quality, safeguarded through CE compliance

Due to the increased loads, inertias, and modified operating limits, the equipment may undergo a “significant modification” subject to certification requirements, necessitating a renewed safety assessment. This includes an updated risk assessment, strength and functional verifications, as well as adjustments to technical documentation and operating instructions. Depending on the risk assessment (EN ISO 12100), a new or revised EU Declaration of Conformity (CE) may be required.The CE marking confirms that a machine or assembly of machines meets the essential EU safety requirements. For operators, it ensures legal marketability within the EU, liability and insurance protection, and verifiably controlled risks during operation. Especially in highly integrated process chains such as aluminium plate manufacturing, CE conformity provides a binding, auditable framework for systematically identifying, mitigating, and monitoring hazards throughout the entire process chain.By extending the product portfolio from 6  to 7 inch plates, cross sections, masses, and handling loads increase. This change has safety and function relevant effects (e.g., higher rolling forces, greater inertias, modified gripping devices and crane loads, different sawing forces, and longer heating and cooling times in heat treatment furnaces). The relevant regulation is the EU Machinery Regulation (EU) 2023/1230.For “significant modifications” to existing machinery, the following applies: If a modification impacts safety and the machine no longer complies with the originally assessed state, a new conformity assessment must be performed (including CE marking, unless the modification is considered “within the intended use” without increasing risk).

Uniform microstructure

Figure 2 shows that the 7 inch plate also exhibits an impressively uniform microstructure compared to the 6 inch plate. Both images (edge T/2) display a continuous, homogeneous etching pattern without noticeable zone transitions, which are quite typical in these thicknesses.The micrographs of the new AMAG 7 inch plates clearly demonstrate that even larger cross sections achieve exceptional homogeneity. From the edge to the plate center, the microstructure remains fine, uniform, and free from inhomogeneities – a visible proof both of the expertise in selecting process parameters and of the high process stability of our hot rolling and heat treatment systems. Thanks to targeted equipment optimization, AMAG achieves for 6061 T651 the same premium properties as in previous 6 inch products. The reproducible microstructure quality, combined with CE certified process safety, makes AMAG the preferred partner for demanding applications in semiconductors, mechanical engineering, and high performance industries.

Tight tolerances for mechanical properties and dimensions

Tables 2a and 2b show the mechanical properties and guaranteed thickness tolerances for the respective plate thicknesses according to the metric (a, mm) and imperial (b, inch) systems. The illustrated mechanical values and tolerances highlight the high performance of AMAG plates in thickness ranges above 150 mm or over 6 inches. In both the metric (EN standards) and imperial (ASTM/AMS) systems, the available alloys 6061 T651 and 6082 T651 ­reliably  meet the required minimum values for tensile strength, yield strength, and elongation while typically achieving AMAG premium levels.At the same time, the tight thickness tolerances according to EN 485 3, such as ±2.6 mm in the metric system or +0.160/−0 inch in the imperial system, demonstrate the excellent control of rolling and heat treatment processes for large cross sections.The combination of high mechanical performance, consistent strength values, and precise dimensional stability makes AMAG’s 6xxx plates a reliable choice for demanding applications in mechanical engineering, toolmaking, robotics, offshore structures, and other high performance sectors where dimensional accuracy, safety, and structural integrity across large thicknesses are critical.