The Wear Responses of the Welded Joints of ASTM A335 Gr. P11 Steels Affected by Accelerated Flow Corrosion.

Montero Montero,Camba Camba,Mier Mier,Filgueira Filgueira,García-Diez García-Diez

doi:10.3390/ma12213630

Abstract

This study shows the effects of wear on welded joints of ASTM A355 Gr. P11 “Seamless Ferritic Alloy-Steel Pipe for High Temperature Service” steels subjected to the welding procedures established by codes B31.1 and ASME III. The standard welding procedure establishes the following steps: a preheating process, welding and post-weld heat treatment. This generates a wear behavior that depends on the thermal cycles to which the different areas of the joint are subjected. The objective of this article was the study of the behavior against the flow-accelerated corrosion of the welded joints of a low alloy steel. There is the possibility of establishing welding procedures other than those established, while maintaining the safety ranges, depending on the field of application for the steel.

Highlights

In power plants, steam pipes are subject to conditions of use that imply the occurrence of the flow accelerated corrosion (FAC) phenomenon
Hardness was lower in the base metal (BM) zone and higher in the fusion zone (FZ) zone for both samples B and C
In sample A, the lowest hardness was obtained in the heat affected zone (HAZ) zone

Summary

Introduction

Steam pipes are subject to conditions of use that imply the occurrence of the flow accelerated corrosion (FAC) phenomenon. Different zones can be distinguished due to the influence of the chemical compositions of the steel and the filler metal, and the temperatures reached during the welding process [2,3,4,5]. Differences in the hardness values in the different zones are obtained [6,7] This hardness variation results in different wear rates caused by the steam flow, which can accelerate the corrosion inside the pipes [8,9,10]. The wear resistance of these three zones in a welded joint with the standard procedure was evaluated, since variations in the microstructure of the Materials 2019, 12, 3630; doi:10.3390/ma12213630 www.mdpi.com/journal/materials.

Material

Experimental Work

Results and Discussion

Microstructure

Sample

Conclusions