Stainless Steel and Nickel Alloys - Metallographic Sample Preparation
Stainless steel and nickel (Ni) Alloys can be prepared for metallurgical analysis using OnPoint Abrasives' procedure and consumable supplies. We have provided a step by step process for metallographic sample preparation of stainless steel and nickel (Ni) alloys.
Sectioning: Section specimen with MultiSec abrasive blade or multi-purpose diamond blade.
Mounting: For best results, compression mount specimen using EpoMount epoxy powder. The high hardness of the epoxy will offer superior edge retention and promote flatness across the entire surface of the mount. For samples that require castable mounting, we recommend using EpoPro liquid epoxy system.
Grinding and Polishing: In this section, we've provided two methods for preparing your specimen for analysis, Traditional Method and Advanced Method.
The Traditional Method uses a series of Silicon Carbide grinding papers to first planarize and grind the surface to around 3-5 micron (1200 grit), before moving to polishing steps using suspensions and cloths. This method is effective for general purpose metallography, although it can introduce some relief, or rounding of the specimen's edge.
TRADITIONAL METHOD FOR PREPARING STAINLESS STEEL & NICKEL ALLOYS FOR METALLOGRAPHIC ANALYSIS
|
Step | Abrasive | Surface | Lube | Load/Sample | RPM | Time |
1 | 240 Grit | CarbiPro SiC | Water | 6 lbs | 200 | Planar |
2 | 320 Grit | CarbiPro SiC | Water | 6 lbs | 200 | 1:00 |
3 | 400 Grit | CarbiPro SiC | Water | 5 lbs | 200 | 1:00 |
4 | 600 Grit | CarbiPro SiC | Water | 5 lbs | 200 | 1:00 |
5 | 800 Grit | CarbiPro SiC | Water | 5 lbs | 200 | 1:00 |
6 | 1200 Grit | CarbiPro SiC | Water | 5 lbs | 200 | 1:00 |
7 | 1µm Diamond | ProDac Cloth | Lubricant/Extender | 5 lbs | 150 | 2:00 |
8* | FinalFloc Cloth | - | 5 lbs | 150 | 2:00 |
*For the final step, alternate between the alumina and ProPrep colloidal silica at 20 second intervals. Finish with a large dose of alumina when 0:30 seconds remain.
Note: Clean specimen by gently scrubbing the surface with a cotton ball under running water. Repeat until all alumina is removed. Use of an ultrasonic cleaner is highly recommended for samples with high porosity content or intricate geometries.
Our Advanced Method uses one or two steps of SiC grinding paper to initially planarize the mounted specimen. This is followed by a series of "loose" abrasive polishing steps that utilize diamond and alumina suspensions along with polishing cloths. The less aggressive nature of this method preserves the specimen's edge and produces ultra-flat results. This can be critical for analysis such as coating thickness measurements or samples that are examined near the specimen's edge. It is viewed by many that the "advanced" methods of preparation offer superior results and higher consistency when compared to traditional methods.
ADVANCED METHOD FOR PREPARING STAINLESS STEEL & NICKEL ALLOYS FOR METALLOGRAPHIC ANALYSIS
|
Step # | Abrasive | Surface | Lube |
Load/Sample |
RPM | Time |
1 | 180 or 240 Grit | CarbiPro SIC | Water | 6 lbs | 200 | Planar |
2 | 320 Grit | CarbiPro SiC | Water | 6 lbs | 200 | 2:00 |
3 | 9µm Diamond | MasterPlan Cloth |
Lubricant/Extender |
5 lbs | 150 | 5:00 |
4 | 3µm Diamond | ProDac Cloth | Lubricant/Extender | 5 lbs | 150 | 3:00 |
5* | FinalFloc Cloth | - | 5 lbs | 150 | 2:00 |
*For the final step, alternate between the alumina and ProPrep colloidal silica at 20 second intervals. Finish with a large dose of alumina when 0:30 seconds remain.
Note: Clean specimen by gently scrubbing the surface with a cotton ball under running water. Repeat until all alumina is removed. Use of an ultrasonic cleaner is highly recommended for samples with high porosity content or intricate geometries.
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Diabrasive Premium Polycrystalline Diamond Suspension - All Variants
Diabrasive Premium Polycrystalline Diamond Suspensions are the ultimate solution for polishing of your metallographic specimens. Water soluble for ...
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