Quality	Standard	Possible coatings	Alloy concept
CR1	VDA 239-100	UC, EG, GI, GA, AS, ZM	Non IF or IF

Testing direction	Yield Point Re (MPa)	Tensil Strength Rm (MPa)	Elongation type 1 A50 (in %)	Elongation type 2 A80 (in %)	Elongation type 3 A50 (in %)
Q	140 – 300	270 – 410	≥ 29	≥ 28	≥ 30

Mild steels of grade CR1 in accordance with the VDA 239-100 standard are characterized by their excellent formability, which is due to their low yield strength and high elongation at break. These special material properties make CR1 steels ideal for the production of complex components that require extensive forming, such as certain body and structural parts in the automotive industry. The CR1 grade is particularly used in the production of components where there are high demands on formability but no particularly deep drawing processes are required.

CR1 steels are divided into two main types: non-interstitial-free (non-IF) and interstitial-free (IF) steels. While both variants are similar in their basic material properties, the IF variant offers even better formability. This improvement is achieved through a specific chemical composition. IF steels, i.e. interstitial-free steels, contain extremely small amounts of carbon and nitrogen, which are neutralized by the addition of stabilizing elements such as titanium and/or niobium. These additives prevent the formation of disruptive impurities in the metal structure and enable a uniform and very fine grain structure, which is particularly advantageous in deep forming processes.

In contrast, non-IF steels have a slightly higher amount of carbon and nitrogen. They are also produced using an aluminum-killed manufacturing process, which means that aluminum is used to calm the steel during the melting process and thus reduce the formation of gases. This improves the surface quality and reduces the likelihood of air inclusions.

Thanks to the combination of low yield strength and high elongation at break, CR1 steels offer excellent formability, which is required for the production of components with complex shapes. The low yield strength means that the steel is plastically deformable even with a small amount of force applied, without snapping back into the elastic range. This is particularly important in applications where the components require both a precise shape and structural integrity. The high elongation at break in turn ensures that the material does not break when deformed and can be bent or pulled to a high degree before it reaches its load limits.

CR1 steels are mainly used in the automotive industry for components that require high levels of formability but do not require extreme deep-drawing capability. Examples include certain interior and exterior trim parts that require precise and uniform shapes without the need for complex deep-drawing processes. Thanks to their good forming properties, these steels can be used in various production processes and are particularly suitable for press and drawing-based manufacturing processes.

The CR1 grade of mild steels according to VDA 239-100 offers a first-class balance between formability and strength and is therefore ideal for numerous industrial applications. Whether as non-IF or IF steel, CR1 materials are characterized by high flexibility and adaptable properties that offer manufacturers a wide range of processing options. The clearly defined composition and production in accordance with VDA 239-100 ensures that the requirements for formability and surface quality are optimally met and that the steels can be used for demanding applications with high dimensional accuracy.