Session: MF-24-02 Matls & Fabrication for Refining-Design & Fabrication Issues Affecting Design Life

Paper Number: 121075

121075 - High Strength Alloys Sa537cl2 and Sa533tpc/ecl2 for Pressure Vessels Applications With Sour Service Requirements 

Steels for sour service applications represent a significant part of global steel business for Oil&Gas industry and some solutions have been successfully used for decades in projects. As of today, the most common materials are Carbon-Manganese (C-Mn) steels as per SA516 plate standard, low or mid-strength, with specific limitations on chemical composition and/or on mechanical properties, associated with specific testing to address the response of the alloys in H₂S containing environment.

 

Even if largely spread, these steel grades also have some drawbacks, mostly consisting in their ability to achieve low-temperature impact toughness. This is mainly due to the chemical balance and heat treatments to be done and imposed by the code and the standard. It can then be extremely challenging to provide materials compliant with some very stringent specifications when projects are located in cold environment remote locations, or when design conditions lead to very low minimum design metal temperatures (MDMTs).

 

A second limitation coming with C-Mn steels is the maximum allowable stresses that are quite low, due to the limitation of strength of theses grades in the standards. It is then sometimes critical for heavy equipments with large diameters and/or high internal pressure, to be able to meet mechanical properties for very thick sections. Reducing thickness can then be a smart solution to get improved designs, especially with up-to-date alloys with better chemical composition balance.

 

Optimization of higher strength alloys SA537cl2 (corresponding to a 420MPa yield strength class material) and SA533tpC/Ecl2 (corresponding to a 500MPa YS class material) has been done by Industeel and these high-strength steel grades have now a large return of experience from field. These alloys can provide higher allowable stresses, hence limiting the product thickness and also the weight, while providing better low-temperature toughness and excellent resistance to harsh sour service environments.

 

This paper provides a deep review of achievable properties with SA537cl2 and SA533tpC/Ecl2, and provides some insights on potential gains that can be expected when switching to these options instead of using conventional low strength Carbon-Manganese materials as per SA516 standard.

Presenting Author: Sylvain Pillot Industeel

Presenting Author Biography: – Master’s Degree in Mechanical Engineering and Materials Science obtained in 2001
– Worked for 16 years at Industeel Research Center as R&D Engineer and Department Head on product development for various applications linked to energy markets (high temperature creep service, cryogenics, refining, hydrogen, …) and hence gave many presentations on Pressure Vessels and Cryogenics materials at PVP, API, NACE, …
– Then worked for 6 years as Technology Coordinator for all Business Units of ArcelorMittal group, with a focus still on Energy Segments
– Now, since January 2023 responsible for marketing of Pressure Vessels and Cryogenic grades at Industeel, with a transverse role on product development for the Global Energy Transition markets.

Authors:

Sylvain Pillot Industeel
Ngomo Valéry Industeel