Increasing Low-Temperature Toughness of 09Mn2Si Steel through Lamellar Structuring by Helical Rolling

Sergey Panin,Dmitry Moiseenko,Ivan Mishin,Alexander Yakovlev,Siegfried Schmauder,Ilya Vlasov,Julia Gomorova,Pavel Maksimov,Pavlo Maruschak

doi:10.3390/met11020352

Abstract

The aim of the paper was to investigate the helical rolling parameters (a number of passes) for the microstructural modification and the low-temperature impact toughness improvement of the 09Mn2Si High Strength Low-Alloyed (HSLA) steel. In order to achieve this purpose, work spent to crack initiation and propagation was analyzed and compared with patterns of fracture surfaces. The microstructure and impact toughness values were presented in the temperature range from +20 to –70°C. Also, the fracture mechanisms in individual regions on the fracture surfaces were discussed. In addition, a methodology for computer simulation of the process was developed and implemented within the framework of the excitable cellular automata method and its integration with the kinetic theory of fracture. Finally, a theoretical analysis of the effect of grain shapes and orientations on the strain response patterns of a certain meso-volume simulating the material after the helical rolling was carried out.

Highlights

The active development of the Arctic region justifies enhanced requirements for the mechanical properties of materials used for application in the cold climate
High strength low alloyed steels (HSLA) of the X52 grade, which have been used in the pipeline construction for a long time, continue to be of interest
Together with the retention of strain dislocation mechanisms in the steel after the helical rolling (HR) processing, it was possible to ensure the decrease in impact toughness steel with level, the decrease in the test compared to the KCV values at the as-received while there was notemperature significant decrease in impact as-received steel

Summary

Introduction

The active development of the Arctic region justifies enhanced requirements for the mechanical properties of materials used for application in the cold climate. To solve this issue, in particular upon the construction of pipelines, steels of new generations (the X80 and X100 grades, or higher) are being designed, which are characterized by a continuously increasing ratio between ductility and strength [1,2]. High strength low alloyed steels (HSLA) of the X52 grade, which have been used in the pipeline construction for a long time, continue to be of interest Their properties, especially impact toughness at low climatic temperatures, have to be improved.

Objectives

Methods

Results

Conclusion