Quality	Surface refinement	Steel type
CR180IF	+EG, +GI, +GA, +AS, +ZM	Interstitial Free	Details
CR210IF	+EG, +GI, +GA, +AS, +ZM	Interstitial Free	Details
CR240IF	+EG, +GI, +GA, +AS, +ZM	Interstitial Free	Details
CR270IF	+EG, +GI, +GA, +AS, +ZM	Interstitial Free	Details
CR180BH	+EG, +GI, +GA, +AS, +ZM	Bake-Hardening	Details
CR210BH	+EG, +GI, +GA, +AS, +ZM	Bake-Hardening	Details
CR240BH	+EG, +GI, +GA, +AS, +ZM	Bake-Hardening	Details
CR270BH	+EG, +GI, +GA, +AS, +ZM	Bake-Hardening	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.

Interstitial Free (IF) steels are characterized by the absence of interstitial alloying elements such as carbon (C) and nitrogen (N), which are bound by the addition of stabilizing elements such as titanium (Ti) and/or niobium (Nb). This results in a high-purity microstructure that offers excellent forming properties.

Features and benefits

Applications
High-strength IF steels are mainly used in the automotive industry for components that require a high forming depth. Examples are

ake-hardening (BH) steels combine moderate forming properties with a targeted increase in strength during bake-hardening. These steels contain small amounts of carbon, which remains freely movable in the forming process and contributes to an additional increase in strength during heat treatment.

Features and benefits

Applications
Bake-hardening steels are used in safety-critical and aesthetic components such as

Summary
Both high-strength IF and bake-hardening steels in accordance with the VDA 239-100 standard make an important contribution to modern lightweight construction and safety concepts. While IF steels are preferred for complex deep-drawing processes due to their excellent forming properties and surface quality, BH steels offer an optimal solution for dent-resistant outer skin parts thanks to their targeted increase in strength during the bake-hardening process. Both steel groups meet the high requirements of the automotive industry and help to reduce weight and CO₂ emissions without compromising on safety.