Title

Hot Rolled HSLA Strip Steels for Automotive and Construction Applications

Hot Rolled HSLA Strip Steels for Automotive and Construction Applications

Authorship

HERMAN, JEAN-CLAUDE

HERMAN, JEAN-CLAUDE

I am this author

DOI

10.5151/2594-5297-LA11855

Downloads

Abstract

The major objective of the steel industry is to deliver consistent material minimizing yield losses: very constant properties from coil to coil, along the length, through the width, for a great variety of formats. Consequently, the production of the different grades requires a strict control of the process parameters in order to ensure reproducibility and consistency. Respecting simple rules at the hot strip mill, this objective can be achieved taking the maximum profit from the microalloying additions (grain refinement and precipitation hardening). Ensuring consistency on hot rolled strips needs to define the process window for each step of the rolling tine (rolling in the finishing mill, cooling and coiling). Any deviation outside the defined process window will induce a large variation of the final mechanical properties. The process window is not unique and depends on the steel chemistry. Two main important parameters have to be under control: * along the strip length, it is of prime importance to ensure a constant strain accumulation, that is achieved through an appropriate selection of the Tnr, according to the head end entry temperature, *the cooling rate that has to be selected above a critical value according to the steel transformation temperature.

The major objective of the steel industry is to deliver consistent material minimizing yield losses: very constant properties from coil to coil, along the length, through the width, for a great variety of formats. Consequently, the production of the different grades requires a strict control of the process parameters in order to ensure reproducibility and consistency. Respecting simple rules at the hot strip mill, this objective can be achieved taking the maximum profit from the microalloying additions (grain refinement and precipitation hardening). Ensuring consistency on hot rolled strips needs to define the process window for each step of the rolling tine (rolling in the finishing mill, cooling and coiling). Any deviation outside the defined process window will induce a large variation of the final mechanical properties. The process window is not unique and depends on the steel chemistry. Two main important parameters have to be under control: * along the strip length, it is of prime importance to ensure a constant strain accumulation, that is achieved through an appropriate selection of the Tnr, according to the head end entry temperature, *the cooling rate that has to be selected above a critical value according to the steel transformation temperature.

Keywords

HSLA, Hot rolled strips, Process windows

HSLA, Hot rolled strips, Process windows