Production and progress work of plates for pipes with strength level of X80 and above

Abstract

The paper has compiled the actual status for grades X80 and X100 from a point of view of a plate manufacturer. An outlook for a possible extension of feasibility and further development is also given. It can be summarized: 1) plates for gas transporting pipes with strength level of grade X80 are nowadays available up to 25.4 mm and can be produced with the same reliability and reproducibility as lower grades; 2) extension of grade X80 to higher plate thickness even in combination with very low design temperature is practicable; 3) during development stages of grade X100 different approaches has been applied. The current preferred approach to produce plates for pipes with design temperature of 0 °C makes use of a low carbon content in combination with a medium carbon equivalent. So called HACCII process is applied to produce these plates. Plates in thickness up to 20 mm for pipe diameter up to 36¹¹ (~914 mm) have been produced with adequate properties; 4) further development is required and started to extent grade X100 to higher thickness, higher pipe diameter and lower design temperatures.