Quality	Surface type
HR210LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR240LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR270LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR300LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR340LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR380LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR420LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR460LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR500LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR550LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR600LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR650LA	Surface for non-outer skin parts – “U”, Unexposed	Details
HR700LA	Surface for non-outer skin parts – “U”, Unexposed	Details

Hot-rolled micro-alloyed steels in accordance with the VDA 239-100 standard are an essential component of modern lightweight construction concepts in the automotive and mechanical engineering industries. Their outstanding properties make them ideal for applications where high strength, good formability and optimized weldability are required.

Definition and classification
Microalloyed steels obtain their mechanical properties through small additions of alloying elements such as niobium (Nb), titanium (Ti) and vanadium (V). These elements act as grain refiners and promote the precipitation of carbides, nitrides or carbonitrides, which increase strength while maintaining good ductility. In the VDA 239-100 standard, hot-rolled micro-alloyed steels are classified according to the following characteristics:

One example of such a steel grade is HR500LA, a hot-rolled steel with a minimum yield strength of 500 MPa, which is suitable for structurally critical applications.

Properties and advantages
Hot-rolled microalloyed steels are characterized by a combination of high strength, good toughness and economical workability. The main advantages of these materials are

Production and process control
Hot-rolled microalloyed steels are produced using a controlled rolling process in which the microstructure is specifically adapted. The addition of alloying elements such as calcium (Ca) or rare earth metals (e.g. cerium) enables the shape and distribution of the sulphide inclusions to be controlled. This improves edge elongation and fatigue strength, especially for safety-relevant components.

Areas of application
Hot-rolled micro-alloyed steels are typically used in the automotive industry and in agricultural machinery. Examples include

Summary
Hot-rolled microalloyed steels in accordance with VDA 239-100 offer an excellent balance between strength, formability and workability. Their versatile properties and adaptability to specific requirements make them a key component in modern production technology. With their wide range of applications, they make a significant contribution to more efficient and sustainable production.