Welding of CRA Clad Materials Using the Three-Layer Approach

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Back to Core Research Programme AMorph – 4D Printing for Field Morphing Structures Automation of Composite and Hybrid Joining Process Coaxial Wire Additive Manufacturing Processes and In-Line Monitoring Tools Development of Coded Excitation Technique for Non-Metallic Pipes Inspection Development of Digital Twin technology as a demonstrator for real-time integrity assessment of crack growth in tensile specimens Development of Friction Stir Welding (FSW) for Hydrogen Fuel Storage Tanks Development of Leak-Before-Break Hydrogen Storage Composite Pressure Vessels With Polymeric Liner Establishing Assessment Methods for Determining Safe Service Limits of High-Temperature Materials in Extreme Environments Fracture toughness in aggressive environments: effect of crack monitoring techniques on test results In-process detection and non-destructive testing of electron beam weld imperfections Internal Bore Coatings for Applications in Corrosion and Hydrogen Environment Joining of Additively Manufactured Materials Long term behaviour of polymeric liner materials/coatings in hydrogen service Techniques for High Temperature Ultrasonic Inspection of Arc Welding Ultimate Leverage Fund

Project Code: 0903-02

Objectives

Review potential processes for mechanised three layer (intermediate buffer layer) welding of CRA clad components.

Carry out trials using pure Fe and pure Ni wires and shortlisted processes. Carry out inspection and metallurgical evaluation including mechanical strength testing as per DNV OS F101:2007.

Compare techno-commercially the approach of welding the entire joint using CRA weld metal vis--vis the three-layer approach.

Project Outline

Experimental trials will be carried out to evaluate the option of three layered girth welds in piping and establish the key parameters for achieving a weld that is fit-for-purpose. Feedback from the use of such welding procedures in stainless steel clad components suggests that the weldability of the buffer layer is very different to that of both high Nickel and carbon steel consumables, and that the weld pool is difficult to control (highly fluid). Quality control issues can arise with the use of three different consumables in the same joint, with the buffer layer having reduced mechanical properties compared to the high Nickel and carbon steel consumables and the base materials. Additionally, the interface of three consumables with two base materials and the different properties and characteristics of each, increases the likelihood of weld defects to occur. With so many interfaces, the resultant metallurgical microstructure analysis can be difficult to determine and control and the non-destructive examination of such welds will also become increasingly difficult. The use of such a three-layered weld might preclude the necessity for PWHT, which will also be reviewed as a part of the program. However, successful resolution of the above issues will provide improved fabrication options for future developments involving clad systems, particularly if PWHT can be avoided.

Relevant Industry Sectors

Oil and Gas, Power, Nuclear

Technical and Economic Benefits

Improved fabrication options for future developments involving clad systems.

Industrial Member Report

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Welding of CRA Clad Materials - Three Layer (Buffer Layer) Approach