ABRASIVE CUTTING
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INTRODUCTION 
The first step in preparing a specimen for metallographic or microstructural analysis is to locate the area of interest. Sectioning or cutting is the most common technique for obtaining this area of interest. Proper sectioning has the following characteristics:
- Flat and cut close to the area of interest
- Minimal microstructural damage
- Smeared (plastically deformed) metal
- Heat affected zones (burning during cutting)
- Excessive subsurface damage (cracking in ceramics)
- Damage to secondary phases (e.g. graphite flakes, nodules or grain pull-out)
ABRASIVE BLADE SELECTION GUIDELINES
Selecting the correct abrasive blade is dependent upon the design of the cut-off machine and to a large extent the operator preference. Abrasive blades are generally characterized by bond type and hardness. Determing the correct blade is typically dependent upon the material or metal hardness and and whether it is a ferrous or a non-ferrous metal. In practice, it often comes down to smell and blade life because resin/rubber blades smell more because the rubber will burn slightly during cutting, however resin/rubber blades do not wear as fast and therefore last longer. On the other hand, resin blades generally do not produce the burnt rubber odor, but do break down faster. The resin blades also provide a modestly better cut because the cutting abrasive is continually renewed cuts cleaner.
Also note that in the past that resin/rubber blades have been more popular in the US market, however there has been more of a trend towards resin bonded abrasives. Conversely, resin bonded blades have typically been more widely used in the European market.
SUMMARY:
| Material | Composition | Recommended Blade |
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| Soft non-ferrous metals (aluminum, brass, zinc, etc.) | Alumina/ resin bonded | MAX-E |
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| Hard non-ferrou metals (titanium, zirconium, etc.) | Silicon carbide / resin-rubber bond | MAX-C |
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| Soft steels | Alumina/ resin bonded | MAX-E |
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| Hard and case hardened steels | Alumina/ resin bonded | MAX-D |
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| Universal thin resin/rubber blade | Alumina / resin-rubber bond | MAX-A |
ABRASIVE CUTTING PROCESS DESCRIPTION
Abrasive Sectioning - Abrasive sectioning is primarily used for ductile materials. Examples include metals, plastics, polymer matrix composites, metal matrix composites and rubbers. Proper selection of abrasive blades requires an understanding of the relationship between the abrasive particle, abrasive bonding and the specimen properties.
- Abrasive Type - Today's high performance abrasive blades use alumina abrasives because alumina is a moderately hard and relatively tough abrasive.
- Bonding Material - The hardness and wear characteristics of the specimen determine which resin system is the best for abrasive cutting. For hard materials, the specimen wears or breaks down the abrasive, thus to optimize sectioning, new abrasives must be constantly exposed. Therefore softer or more brittle resin systems must break down at a rate similar to how the abrasive fractures or dulls.
RECOMMENDED ABRASIVE CUTTING PROCEDURES
- Select the appropriate abrasive blade
- Secure specimen - improper clamping may result in blade and specimen damage
- Check coolant level and replace when low or excessively dirty. Since abrasive blades breakdown during cutting they produce a significant amount of debris.
- Allow blade to reach its operating speed before beginning the cut.
- A steady force or light pulsing action will produce the best cuts and minimize blade wear characteristics as well as the maintain sample integrity (no burning).
CUTTING FLUIDS
Lubrication during abrasive cutting and diamond wafer cutting are required to minimize damage and to remove the cutting debris or swarf. For abrasive cutters the proper cutting fluid can have the added benefit of coating the cast iron bases and fixtures to eliminate corrosion and rusting of the cutter.
Abrasive cutting fluid - The ideal cutting fluid for abrasive cutting is one that removes the cutting swarf and degraded abrasive blade material. It should have a relatively high flash point because of the sparks produced during abrasive sectioning.
ABRASIVE SECTIONING TROUBLE SHOOTING
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Symptom |
Cause |
Action |
Chipped or broken blade |
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Bluish color on specimen |
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ABRASIVE BLADE PRODUCT DESCRIPTIONS
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Abrasive Blades (32 mm / 1.25-inch arbor) (Qty 10 per package) |
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Description |
10-inch |
12-inch |
14-inch |
16-inch |
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Soft non-ferrous materials (aluminum, brass, zinc, etc.) |
MAX-C250 |
MAX-C300 |
MAX-C350 |
MAX-C400 |
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Hard non-ferrous materials |
MAX-C250 |
MAX-C300 |
MAX-C350 |
MAX-C400 |
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Soft steels |
MAX-E250 |
MAX-E300 |
MAX-E350 |
MAX-E400 |
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Case hardened steels |
MAX-D250 |
MAX-D300 |
MAX-D350 |
MAX-D400 |
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Hard steels |
MAX-D250 |
MAX-D300 |
MAX-D350 |
MAX-D400 |
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Universal Thin Blade |
MAX-A250 |
MAX-A300 |
MAX-A350 |
MAX-A400 |
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Abrasive Cutting Fluid |
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Description |
Quantity |
Part No. |
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MAXCUT Cutting Fluid (32 oz) |
32 oz |
MAXCUT-1000-32 |
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MAXCUT Cutting Fluid (1/2 gallon) |
1 gallon |
MAXCUT-1000-64 |
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MAXCUT Cutting Fluid (1 gallon) |
1 gallon |
MAXCUT-1000-128 |
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MAXCUT Cutting Fluid (5 gallons) |
5 gallons |
MAXCUT-1000-5G |
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MAXCUT 2 Cutting Fluid (32 oz) |
32 oz |
MAXCUT2-1000-32 |
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MAXCUT 2 Cutting Fluid (1 gallon) |
1 gallon |
MAXCUT2-1000-128 |
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MAXCUT 2 Cutting Fluid (1/2 gallon) |
1 gallon |
MAXCUT2-1000-64 |
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MAXCUT 2 Cutting Fluid (5 gallons) |
5 gallons |
MAXCUT2-1000-5G |
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