Materialographic Preparation
Materialographic Preparation involves a sequence of techniques used to prepare the true structure of a specimen for analysis. Sectioning or cutting is where most specimen preparation for analysis begins, followed by mounting if it is required to help assist with mechanical preparation and/or analysis. Mechanical grinding and polishing are the key processes to produce reflective and deformation free surfaces.
For homogenous metals electrolytic preparation can be a substitute or supplement to mechanical processes. Etching is used to create contrast and reveal structural features within the surface.
It’s important to understand the principles of operation of each technique and how the different process parameters affect the specimen surface and material to help choose suitable consumables and methods to minimise deformation to the specimen surface and creation of artefacts during preparation.
Sequence of Processing Steps
Cutting
Equipment Name | Struers Accutom-50 | ||
|---|---|---|---|
Specifications | Cutting Speed | 300 – 5000rpm | |
| Feed Speed | 0.005 – 3.000 mm/s, adjustable in steps of 0.005 mm/s | ||
Max Positioning Speed | Y = 13 mm/s, X = 13 mm/s | ||
| Force Limits | Low = ~20N, Med = ~40N, High = ~60N | ||
| Positioning Range | Y direction = 105 mm (precision 0.1 mm), X direction = 60 mm (precision 0.005 mm) | ||
| Maximum length Cut-off sample | 30 mm, 140 mm at Ø 20 mm | ||
| Maximum length of sample to be clamped | 225 mm | ||
| Maximum Sample Cross Section | Ø127 mm cut-off wheel and Ø42 mm flange = Ø40 mm (without rotation), Ø 80 mm (with rotation) | ||
SOP | |||
Instruction manual | |||
Resources | |||
Booking address | *G SEBE ENG Lab Eqpmt KE2.101 Precision cut-off machine | ||
Heat Treatment
Information to come.
For assistance, contact the Materials team
Mounting
Equipment Name | Struers CitoPress-10 | ||
|---|---|---|---|
Specifications | Mounting Unit | Ø30 mm | |
| Mounting Pressure | 50 – 350 bar in steps of 25 bar | ||
Mounting Heating Time | 1 – 15 min in steps of 0.5 min | ||
| Mounting Heating Temperature | 80 – 180 °C in steps of 5°C | ||
| Mounting Cooling Time | 1 – 15 min in steps of 0.5 min | ||
| Mounting Cooling Rate | High = full flow (4.8L/min), Med = 20% of full flow, Low = 5% of full flow | ||
| Sensitive Option | Dual phase heating and pressure for fragile/porous specimens | ||
SOP | Hot mounting on CitoPress-10 SOP (PDF, 79.6 KB) | ||
Instruction manual | |||
Resources | How to Select a Mounting Method (PDF, 58.4 KB) About Mounting (PDF, 571.6 KB) Hot Mounting Resin Selection Guide | ||
Booking address | *G SEBE ENG Lab Eqpmt KE2.101.02 Hot-mounting press | ||
Mechanical/Electrolytic Preparation
Equipment Name | Struers LaboPol-21 & LaboForce-3 System | ||
|---|---|---|---|
Specifications | Cutting Speed | 300 – 5000rpm | |
| Feed Speed | 0.005 – 3.000 mm/s, adjustable in steps of 0.005 mm/s | ||
Max Positioning Speed | Y = 13 mm/s, X = 13 mm/s | ||
| Force Limits | Low = ~20N, Med = ~40N, High = ~60N | ||
| Positioning Range | Y direction = 105 mm (precision 0.1 mm), X direction = 60 mm (precision 0.005 mm) | ||
| Maximum length Cut-off sample | 30 mm, 140 mm at Ø 20 mm | ||
| Maximum length of sample to be clamped | 225 mm | ||
| Maximum Sample Cross Section | Ø127 mm cut-off wheel and Ø42 mm flange = Ø40 mm (without rotation), Ø 80 mm (with rotation) | ||
SOP | Grinding on LaboPol-21 SOP (PDF, 77.8 KB) | ||
Instruction manual | |||
Resources | See below | ||
Booking address | *G SEBE ENG Lab Eqpmt KE2.101.02 Grinding machine | ||
Equipment Name | Struers Tegramin | ||
|---|---|---|---|
Specifications | Disc Diameter | 250 mm | |
| Disc Speed | 40 – 600 rpm, variable | ||
Rotational Direction | Counter-clockwise | ||
| Head Speed | 50 – 150 rpm, variable | ||
| Rotational Direction | Clockwise or Counter clockwise | ||
SOP | Polishing on Tegramin-25 SOP (PDF, 77.7 KB) | ||
Instruction manual | |||
Resources | See below | ||
Booking address | *G SEBE ENG Lab Eqpmt KE2.101.02 Polishing machine | ||
Resources
Etching
This step is optional. Etchants are first categorised based on the size of the features to be revealed and analysed; macro or micro.
The etchant used depends on the microstructural features to be revealed. For Iron and Carbon steel, stainless steel and superalloys, microstructural features include:
- Bainite and granular bainite
- Ferrite grains and their grain boundaries, cold-worked ferrite, delta ferrite
- Carbides and their grain boundaries, carbide networks, sensitised carbides
- General alloy segregation
- Martensite structure, as quenched or tempered
- Pearlite
- Sigma phase.
For more information refer to the ES Laboratory website and for assistance, contact the Materials team
Analysis
Information to come.
For assistance, contact the Materials team