Vanadium - Transforming Possibilities

Application of V-N Microalloyed Technology on Section Steel

Abstract:

The production of the section steel can be backdated to a long time ago. With plenty of grades and sizes, they are widely used in many industries including construction, machinering manufacture, shipbuilding, railway, bridge, mining, defense and agriculture. Although the ratio between plate and long products has been increasing worldwide, the percentage of the section steel remains at a high level (30 – 60%). Except for a small amount which require for control-rolling, cooling or heat-treated after rolling, most of the section steels are supplied in the as-rolled conditions with lower requirements for properties and especially for the impact toughness.

Generally, the yield strength is typically lower than 235MPa, and no low-temperature impact requirement or only room temperature impact toughness requirement. However, the property requirements for section steel are increasing along with the extension of their application field, especially in high-end equipment manufacturing or project like large vessel and high-voltage transmission tower. Such requirements focus on higher yield strength (above 390 – 420 MPa), improved low-temperature toughness (impact at -20 or -40°C), larger sizes, and easier welding. The comprehensive properties of section steel improved rapidly with the progress of production equipment, process, quality and alloy designing, for instance the higher metallurgical quality of product; the enhanced automation, rolling and production capacity; application of new TMCP and microalloying technology.

Keywords:

 V-N microalloying technology, section steel, pass rolling, bulb flat steel, angle steel, H-beam steel