Quality	Surface refinement	Alloy concept
CR1	+EG, +GI, +GA, +AS, +ZM	Non-IF or IF	Details
CR2	+EG, +GI, +GA, +AS, +ZM	Non-IF or IF	Details
CR3	+EG, +GI, +GA, +AS, +ZM	Non-IF or IF	Details
CR4	+EG, +GI, +GA, +AS, +ZM	Non-IF or IF	Details
CR5	+EG, +GI, +GA, +AS, +ZM	Non-IF or IF	Details
CR6	+EG, +GI, +GA, +AS, +ZM	Non-IF or IF	Details
HR0	+EG, +GI, +GA, +AS, +ZM		Details
HR2	+EG, +GI, +GA, +AS, +ZM		Details

Mild steels according to VDA 239-100 are specially designed for high formability and excellent surface quality and are mainly used in the automotive industry and other sectors that place high demands on the formability and surface quality of their materials. The VDA 239-100 standard classifies these mild steels, in particular cold-rolled (CR) and hot-rolled (HR) variants, according to specific quality classes that are tailored to the respective rolling type and forming quality.

The designation of these steels is made up of the type of rolling (cold or hot strip) and a grade from 1 to 6. The higher the grade, the better the formability of the material.

Cold-rolled steels offer excellent surface quality and precise thickness tolerance, making them ideal for applications where both high surface quality and precise dimensional accuracy are required. The grade class for cold-rolled steels ranges from CR1 to CR6:

Hot-rolled steels in accordance with VDA 239-100 are available in HR0 and HR2 grades:

A special feature of soft steels according to VDA 239-100 is their specially adapted chemical composition. IF steels (interstitial-free steels), for example, have a very low carbon content of less than 0.02%, which significantly improves their formability. However, the manufacturer has the freedom to adapt the alloy concept within the specified limits to meet specific requirements. This enables a high degree of flexibility and efficiency in production, as the steel can be optimized depending on the application.

A typical example would be the designation “VDA 239 CR4-EG29/29-E”. This is a cold-rolled soft steel of grade 4, which is electrolytically galvanized and has a zinc coating of at least 29 g/m² per side. This variant meets the surface quality requirements for exterior parts and is therefore particularly suitable for visible components such as body parts.

Thanks to the precise definition and classification in accordance with VDA 239-100, this standard provides a reliable basis for the selection and use of mild steels with specific properties and areas of application.