Patent ID: 6089066
Filing Date: 2000-07-18
Classification: B21B

Abstract:
A process for producing a hot-finished tube of steel comprising the steps of:feeding a bloom to a three-roll rotary piercing mill, the bloom having been continuously cast from pretreated, degassed, and deoxidized liquid steel comprising one of carbon steel, alloyed steel and high-alloy steel, separated into charge lengths, and heated to a forming temperature;massively reducing the bloom in the three-roll rotary piercing mill for forming a massively reduced bloom by reducing a cross-sectional area of the bloom to an amount within the range including 50% to 80% of the original cross-sectional area of the bloom; andpiercing the massively reduced bloom with an axially fixed piercing mandrel in the three-roll piercing mill to form a hollow billet.