Stress corrosion cracking occurs in systems made from carbon steel, stainless steel, and other metals, and it requires expert inspection and analysis to find and analyze it. G2MT Labs uses state-of-the-art technology for stress corrosion cracking (SCC) inspection; new technologies that allow early detection and repair/monitoring of areas that are susceptible to SCC. As the name implies, stress corrosion cracking  is intimately tied to stress levels in pipelines and SCC can often go unnoticed to the naked eye while microscopic damage occurs underneath the surface.
Is it really stress corrosion cracking?
Identifying stress corrosion cracking is a challenge because the worst damage usually happens below the surface where it remains unseen. There is also a long-standing debate on the naming of corrosion, which includes a variety of more specific type with names such as sulfide stress corrosion cracking, hydrogen-assisted stress corrosion cracking. An enormous amount of failures have been attributed to stress corrosion cracking over the last century.
Certain areas of pipelines are more susceptible to SCC, particularly welds and areas of pipeline damage such as dents, bends, and gauges. Nondestructive inspection techniques must be able to accurately distinguish between seam welds and other pipeline features, and then discern SCC from those signals. Our SCC inspection experts have the experience to find SCC and provide an effective RBI or FFS analysis to help you determine how to proceed.
Hydrogen-Induced Stress Cracking
In many cases, “SCC” is really hydrogen-induced stress cracking: hydrogen absorbed in the metal (from fabrication, welding, cathodic protection, or corrosion) collects in high-stress areas. Stress corrosion cracking commonly occurs in brass, steels, stainless steels, aluminum alloys, copper, and titanium.
Stress Corrosion Cracking Testing and Analysis
To determine what is present, we offer a variety of destructive and nondestructive analytical services:
- Field Metallographic Replication
- NDE Services including UT, Eddy Current, and PMI
- Fitness-for-Service and RBI Programs
- NACE Stress Corrosion Cracking Testing
How to Prevent Stress Corrosion and Hydrogen-Induced Cracking
Stress corrosion cracking requires stresses and a corrosive environment. When these are present, it is up to the plant operators to select appropriate materials that are cost-effective. These are the basic steps for controlling SCC:
- Selection of Materials – The susceptibility to SCC is known for many environments and materials, and can be used to select appropriate materials with resistance to SCC.
- Design – Appropriate design can practices can reduce the highest stresses in the structures.
- Control of Stresses – Stress relief heat treatments, surface processing (shot peening and similar processes), and hydrostatic testing can all reduce the susceptibility to SCC.
- Control of Environment – Many times this is not possible, but the environment factor can be modified by inhibitors, coatings, and potential control, among other methods.
To learn how our stress corrosion cracking analysis team can help you, please call us at 888-308-9084 or go here:LET'S GET STARTED!
Stress Corrosion Cracking Resources
- Overview of Stress Corrosion Cracking PDF
- SCC at Corrosion Doctors
- NACE SCC Page
- Stress Corrosion Cracking Lecture PDF
Stress Corrosion Cracking poetry (from the corrosion clinic website):
The image of stress corrosion I see
Is that of a huge unwanted tree
Against whose trunk we chop and chop,
But which outgrows the chips that drop;
And from each gash made in its bark
A new branch grows to make more dark
The shade of ignorance around its base,
Where scientists toil with puzzled face.
(by S P Rideout 1967)