Ferrite testing is a fast, inexpensive, and accurate process that measures the percentage of ferrite in stainless steel–specifically austenitic and duplex stainless steel.
Acuren’s material testing technicians evaluate the ferrite content in your stainless steel microstructures to ensure proper toughness, corrosion resistance, and crack prevention.
Ferrite testing is used in a range of industries, including:
- Oil and gas
- Pulp and paper
- Power generation
- And other industries
What is Ferrite?
Ferrite is one of the metallurgical phases or components found in the microstructure of both austenitic and duplex stainless steels.
In austenitic stainless steel weld metal, ferrite influences:
- Mechanical properties
- Weldability (solidification cracking tendencies)
- Corrosion resistance
In duplex stainless steels, ferrite influences:
- Mechanical properties
- Corrosion performance
Proper ferrite content provides a balance between ductility, toughness, corrosion resistance and crack prevention.
What can Ferrite Testing do?
- Assess ferrite content in stainless steel welds and overlays in field and laboratory settings
- Determine ferrite content percentages of duplex stainless steel piping, pressure vessels, tanks, castings, mechanical components
- Satisfy the requirements of specification such as API 938C, API 582, NACE MR0175, NACE MR0103
Why Use Acuren for your Ferrite Testing needs?
Potential failures or increased maintenance costs due to in-service corrosion, cracking or poor mechanical properties, can be avoided by utilizing Acuren’s ferrite testing services.
Acuren has technicians and engineers throughout North America with decades of experience and can offer this service to a range of industries:
Expert ferrite testing technicians
Our technicians are qualified according to specific procedures within our documented quality program , and technicians are audited to ensure competence over time.
The Acuren technicians that perform this testing are often specific metallurgical technologists and understand what the results mean in relation to the material properties. Not all testing organizations have this level of rigor in their quality program, nor the level of expertise within their technician pool of resources.
Additionally, Acuren employs approximately 100 engineers which are trained and qualified to make recommendations for customers that need additional assistance when interpreting results or making decisions on the best course of action based on the findings of the test.
What is a desirable ferrite content percentage ?
The proper percentage of ferrite depends on the type of stainless steel you are working with.
Ferrite content in austenitic stainless steel
The presence of ferrite in the range of 4-8% in austenitic stainless steel welds is ideal. This percentage has proven effective in controlling micro-cracking of weld metal during cooling.
Ferrite content in duplex stainless steel
In duplex stainless steels, 35 to 65% ferrite is preferred, though 50% is optimum. This ensures corrosion resistance, toughness and strength.
How is ferrite content measured?
Testing ferrite content is fast, and results are immediate.
- A probe is placed on the material being investigated, and a closed magnetic circuit is formed. This allows us to measure the magnetic permeability
- This permeability is measured against standard percentages of other materials with known ferrite content.
- The permeability of the material being analyzed indicates the ferrite content percentage..
- The ferrite content is read from a digital-readout.
Does the testing damage the material?
The technique we use is nondestructive. The surface to be tested must be clean and smooth.
How accurate is ferrite testing?
Calibration pieces are used to ensure accuracy, but results can be influenced by shape, size and surface condition of the component. Typical accuracy within the industry is +/-5%.
Richardson Oilseed is one of Canada’s oldest and largest fully-integrated crushing, refining, processing and packaging operations. In the absence of timely manufacturer support for a critical equipment issue, the full time onsite Acuren Condition Monitoring Specialist was able to diagnose and provide a detailed correction path on a defective trunion bearing.
When our large refining customer was faced with the requirement to upgrade one of their major crude storage tanks they turned to Acuren’s expertise. We were able to eliminate the hydrostatic test activities through the application of Fitness For Service (FFS) Methodologies as permitted by API 653.