Correlation of Mechanical Properties for Steel and Weld Regions

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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: 36205

Start date and planned duration: January 2025, 12 months

Objective

To identify whether a correlation between hardness and fracture toughness can be determined for steels.

Project Outline

TWI has previously developed correlations between hardness and yield strength for parent materials, weld metals and HAZs in C-Mn steels. These were originally published in TWI’s Industrial Member publication “Bulletin” and have subsequently been incorporated into selected British Standards (Hart, 1975, Pargeter, 1978, BSI, 2019)

Fracture toughness is said to decrease with increasing hardness, but this is quoted as a ‘rule of thumb’, with no manner of determining an approximate value of toughness from hardness. It is important to determine whether this correlation truly exists, or is limited to the findings associated with a single steel composition or could be applied more widely.

The existing body of information available from the TWI Research reports will be searched to identify data concerning hardness and fracture toughness. The data identified will be collated in a database and used to identify whether the correlation of hardness and toughness exists, and if so, develop a relationship to link these two properties.

Industry Sectors

- Oil and Gas

- Power

- Construction

Benefits to Industry

If the correlation can be determined, it would allow approximations of fracture toughness to be made from hardness data, which may arise from weld procedure qualification testing or from failure investigations, where the test material is limited.