Session: MF-20-02 Material Quality and Failure Analysis-2

Paper Number: 125505

125505 - Metallurgical and Fracture Toughness Variability Characterization of 2.25cr 1 Mo Plate Steel for Hydroprocessing Reactors 

Fracture toughness and temper embrittlement susceptibility are pivotal factors influencing the mechanical integrity of hydroprocessing reactors within oil refineries and chemical plants. Moreover, they exert a notable impact on the minimum allowed pressurization temperature (MPT), thereby affecting the startup and shutdown times. Enhanced fracture toughness at low temperatures and heightened resistance to temper embrittlement lead to a lower permissible MPT setting. Temper embrittlement is the reduction in fracture toughness due to a metallurgical change that can occur in some low-alloy steels as a result of prolonged exposure in the temperature range of about 650 °F to 1070 °F (345 °C to 575 °C). This change causes an upward shift in the ductile-to-brittle transition. Although the loss of toughness is not evident at operating temperature, equipment afflicted by temper embrittlement becomes susceptible to brittle fracture during start-up and shutdown processes. The paper includes a literature review and describes the variability in fracture toughness of 2.25Cr 1Mo steel plate material in function of temperature. Additionally, it presents a case history where high variability was reported in weld deposits. Factors affecting fracture toughness and tempering embrittlement are analyzed and recommendations to maximize fracture toughness and reduce temper embrittlement susceptibility are included. Finally, the paper touches upon technology limitations as dictated by contemporary manufacturing practices. The characterization process incorporates optical microscopy, scanning electron microscopy, hardness, chemistry, impact testing and crack tip opening displacement measurements.

Presenting Author: Andres Acuna Ohio State University

Presenting Author Biography: Andres Acuna, a Ph.D. in Welding Engineering from The Ohio State University (2023) with a mechanical engineering background, brings over 12 years of oil and gas industry experience. He specializes in research and project management related to welding for pipelines, oil platforms, and refineries, dating back to 2008.

His recent projects include Hybrid laser arc welding for pipelines, GMA short-circuit control for pipeline root passes, examination of intermetallic precipitation kinetics in duplex stainless steels, analysis of sigma phase's impact on HDSS toughness, research on wire arc additive manufacturing using HDSS filler metal, CrMo low alloy toughness optimization, SAW flux moisture-diffusible hydrogen correlation, and reheat cracking on Nickel-base alloys.

Andres has recently joined Lincoln Electric's Consumable R&D team, focusing on material development and welding solutions for customers.

Authors:

Andres Acuna Ohio State University
Teresa Melfi Lincoln Electric
Bennik Wim Shell Sarnia Manufacturing Center
Jorge Penso Shell Global Solutions (US) Inc