Quality	Standard	Material No.	Possible Surface Coating:
HCT780T	DIN EN 10338	1.0948	+ZE according to DIN EN 10152 (electrolytically galvanized)
HCT780T	DIN EN 10346	1.0948	+Z, +ZF, +ZA, +ZM (Hot-dip coating)

Testing direction	Yield point Rp0,2 (MPa)	Tensil Strength Rm (MPa)	Elongation A80 (in %)	Strain Hardening Exponent n 10-UE	Bake-Hardening-Index BH2
longitudinal test specimen	450 – 570	≥ 780	≥ 21	≥ 0,16	≥ 40

HCT780T is a high-performance cold-rolled TRIP steel (Transformation-Induced Plasticity) manufactured according to DIN EN 10338 standards. This type of steel combines high strength with exceptional formability, making it ideal for demanding applications, especially in the automotive industry. The special microstructure of HCT780T, which includes both ferrite and retained austenite, imparts its outstanding mechanical properties.

The microstructure of HCT780T consists of a ferrite matrix containing retained austenite. This dual-phase structure is crucial for the TRIP effect, which occurs during deformation. The retained austenite transforms into martensite under plastic deformation, increasing strength while maintaining high ductility. HCT780T achieves a tensile strength of approximately 780 MPa, making it ideal for applications that require both high strength and excellent formability.

In addition to the cold-rolled version, HCT780T is also available as a continuously galvanized steel according to DIN EN 10346. In this process, the steel is continuously immersed in a bath of molten zinc or a zinc alloy, creating a protective zinc layer on the steel’s surface. This coating provides excellent corrosion resistance, increasing the lifespan of the components and enhancing their performance in corrosive environments. Therefore, the galvanized version of HCT780T combines the mechanical advantages of TRIP steel with enhanced corrosion resistance.

HCT780T utilizes the TRIP effect (Transformation-Induced Plasticity), enabled by the steel’s special microstructure. The ferritic base structure contains retained austenite, which transforms into martensite during plastic deformation. This transformation significantly improves the steel’s strength while preserving its ductility. The TRIP effect contributes significantly to the material’s high energy absorption and crash safety, making it particularly suitable for safety-critical applications in the automotive industry.

Compared to HCT690T, HCT780T offers higher tensile strength, making it particularly suited for applications that demand even greater strength. While HCT690T already provides an excellent combination of strength and formability, HCT780T further increases strength while remaining similarly formable. Both steels leverage the TRIP effect to achieve their exceptional mechanical properties, but HCT780T’s higher strength offers an expanded range of applications, particularly where maximum protection and strength are required.

The manufacturing of HCT780T follows a precisely controlled process. Initially, the steel is hot-rolled and then cooled under controlled conditions to achieve the desired microstructure. This is followed by a cold-rolling process, which refines the fine-grained structure and improves the mechanical properties of the steel. A final heat treatment ensures that the steel reaches an optimal balance between strength and formability.

HCT780T is widely used in the automotive industry, where high material performance is required. Due to its high strength and excellent formability, this steel is particularly suitable for manufacturing body parts that require high energy absorption in the event of a collision. Examples include door reinforcements, bumpers, and safety cells. The continuously galvanized version of HCT780T is ideal for applications that require both mechanical performance and high corrosion resistance, such as exterior body parts and underbody components.

The production and application of HCT780T follow the strict guidelines of DIN EN 10338 and DIN EN 10346. These standards ensure that the steel meets high-quality and performance requirements. Regular testing and inspections during the entire production process guarantee that the mechanical properties and corrosion resistance of the steel are consistently maintained and that the steel is suitable for its intended applications.

With the increasing demand for lighter, stronger, and more formable materials, especially in the automotive industry, HCT780T is becoming increasingly important. Its ability to maximize the structural integrity of vehicles while reducing weight contributes to the development of more energy-efficient and safer vehicles. Ongoing advancements in manufacturing processes and coating technologies will further optimize the properties of TRIP steels like HCT780T and open up new application possibilities.

In summary, HCT780T offers an outstanding combination of strength, ductility, and corrosion resistance. Adhering to DIN EN 10338 and DIN EN 10346 standards ensures consistent high quality and performance, making it a preferred choice for modern manufacturing processes.