CR380LA - Cold-Rolled Micro-Alloyed Steel according to VDA 239-100

Quality	Standard	Possible coatings
CR380LA	VDA 239-100	UC, EG, GI, GA, AS, ZM

Quality

Testing direction	Yield Point R_e (MPa)	Tensil Strength R_m (MPa)	Elongation type 1 _A50 (in %)	Type 2 A₈₀ (in %)	Type 3 A₅₀ (in %)
L	380 – 470	450 – 570	≥ 20	≥ 19	≥ 20

Mechanical Properties

C %	Si %	Mn %	P %	S %	Al %	Ti %	Nb %	Cu %
≤ 0,12	≤ 0,50	≤ 1,60	≤ 0,030	≤ 0,025	≥ 0,015	≤ 0,15	≤ 0,09	≤ 0,20

Chemical properties

In the spectrum of micro-alloyed, cold-rolled steels according to the VDA 239-100 standard, the CR380LA grade represents a significant further development. It falls within the medium to upper strength range, offering an ideal balance between strength and formability. This combination of properties is crucial for the automotive industry, as it enables manufacturers to produce body parts that both meet high requirements for passive safety and contribute to weight reduction. The material was specifically developed for applications where conventional steels are no longer sufficient and higher load-bearing capacity is required. Like all grades in this standard, CR380LA is also exclusively designed for use in the automotive sector, where it plays a central role in the manufacturing of Body-in-White structures.

Properties

The outstanding performance of CR380LA is based on a precise coordination of mechanical and chemical properties. According to VDA 239-100, CR380LA must achieve a minimum yield strength (Rp0.2) of 380 MPa, with the minimum tensile strength (Rm) at 450 MPa. Despite these considerable strength values, the material exhibits a minimum elongation at break of 19%. This value is particularly remarkable for a steel of this strength class, as it allows for excellent cold formability. The chemical composition, like with other LA grades, is characterized by a low carbon content. Instead, the strength is achieved by adding micro-alloying elements such as titanium and niobium. These elements ensure a fine strengthening of the microstructure without negatively affecting weldability or cold formability. This means the steel can be easily processed using common welding methods, especially resistance spot welding. The high surface quality of the cold-rolled strip also makes it ideal for coating, such as hot-dip galvanizing, which provides optimal corrosion protection.

Applications

CR380LA is used in automotive production for a variety of components where increased strength is required without restricting design freedom due to insufficient formability. Typical applications include:

Longitudinal Members and Sills: These components form the backbone of the vehicle structure and must efficiently distribute and absorb impact energy in a frontal or side collision.

Seat Frames and Seat Mounts: In these safety-critical parts, CR380LA provides the necessary stability to keep occupants secure during a collision.

Cross Members and Reinforcements: Whether in the dashboard area or as reinforcement in the A-pillar, the material contributes to the stiffness of the passenger compartment and prevents its uncontrolled deformation in the event of a crash.

Floor and Roof Reinforcements: Here, the high strength enables a reduction in material usage and thus weight optimization.

The combination of high strength and good formability makes CR380LA a versatile material for complex molded parts required in automotive body structures.

Conclusion

In summary, CR380LA according to VDA 239-100 is a modern material that bridges the gap between classic formability and increased strength. It’s a reliable solution for engineers and designers aiming for both significant weight reduction and improved crash safety. Thanks to its balanced mechanical properties and excellent workability, this steel significantly contributes to efficiency in series production and enables the development of vehicle generations that meet the highest demands for safety, efficiency, and sustainability. Its role as an essential building block in car body construction is therefore undeniable.