Title

AN ASSESSMENT OF THE ROLE OF MICROALLOYING ELEMENTS IN THE 1980S

AN ASSESSMENT OF THE ROLE OF MICROALLOYING ELEMENTS IN THE 1980S

Authorship

SAGE, A M

SAGE, A M

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DOI

10.5151/2594-5300-13Aciaria-369-386

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Abstract

In the last twenty years high strength low alloy steels, or microalloy steels as they are sometimes called, have become accepted for a wide range of structural applications, ranging from reinforcing bars to pipelines. Other properties are often required together with strength, but these vary widely with the application. The selection of steel composition and rolling/heat treatment procedures is also controlled by the steelmaking, rolling and heat treatment facilities available at the steel plant and the fabrication facilities of contractors. No one microalloying element finds universal application for any one product throughout the world. Every steel plant has to determine for itself the alloy composition and production processes which will combine to enable it to meet the specifications laid down by its customers, with the plant it has available, at lowest total overall cost. In rare cases new plant may be installed to enable specifications to be achieved. This paper attempts to summarise the specification requirements of steels required for different applications and to indicate the roles of the individual microalloying elements, including their merits and disadvantages, in the production of steels under varying conditions. It discusses how the alloys can be used most effectively to produce steels with various combinations of mechanical properties in different plants. The selection of steel composition results from (a) customer requirements, (b) process development, (c) our knowledge of the factors controlling the structure of steel and its relation to properties, and (d) steelmaking and rolling plant available. These are summarised in Fig. 1 and may be called the weft and warp of steel development.

In the last twenty years high strength low alloy steels, or microalloy steels as they are sometimes called, have become accepted for a wide range of structural applications, ranging from reinforcing bars to pipelines. Other properties are often required together with strength, but these vary widely with the application. The selection of steel composition and rolling/heat treatment procedures is also controlled by the steelmaking, rolling and heat treatment facilities available at the steel plant and the fabrication facilities of contractors. No one microalloying element finds universal application for any one product throughout the world. Every steel plant has to determine for itself the alloy composition and production processes which will combine to enable it to meet the specifications laid down by its customers, with the plant it has available, at lowest total overall cost. In rare cases new plant may be installed to enable specifications to be achieved. This paper attempts to summarise the specification requirements of steels required for different applications and to indicate the roles of the individual microalloying elements, including their merits and disadvantages, in the production of steels under varying conditions. It discusses how the alloys can be used most effectively to produce steels with various combinations of mechanical properties in different plants. The selection of steel composition results from (a) customer requirements, (b) process development, (c) our knowledge of the factors controlling the structure of steel and its relation to properties, and (d) steelmaking and rolling plant available. These are summarised in Fig. 1 and may be called the weft and warp of steel development.

Keywords

Microalloying elements, High strength low alloy steels, Steel composition, Mechanical properties, Steel development

Microalloying elements, High strength low alloy steels, Steel composition, Mechanical properties, Steel development