Exploring Equipment Used in Metallographic Preparation

Metallographic specimen preparation is a crucial step in materials analysis, revealing the internal structure and quality of a material. Depending on the material’s hardness or ductility, preparation techniques can vary significantly. Accurate preparation is essential for consistent and reliable microstructural examination.

What is Metallography?

Metallography, or microstructural analysis, involves examining the internal structure of materials (typically metals) under magnification. This process helps determine the material’s composition, processing history, and performance characteristics.

Common Metallographic Analysis Includes:

• Grain size and shape
• Porosity, voids, and cracks
• Phase distribution
• Dendritic structures
• Corrosion and intergranular attack (IGA)
• Coating thickness
• Welds and heat-affected zones (HAZ)
• Graphite nodularity
• Inclusion content and distribution
• Recast layers, carburization, decarburization
• Nitriding depth and HAZ sensitization
• Flow lines and filler orientation

Key Equipment Used in Metallographic Preparation

1. Sectioning (Cutting)

Metallurgical Cutting Machines

Sectioning is the first step in sample preparation. Cutting machines are designed to cut materials without altering their microstructure.

• Wet cutting uses coolant to reduce heat and prevent sample damage.
• Dry cutting is used for heat-tolerant materials.

Cutting Consumables

• Abrasive Blades (silicon carbide, alumina) and Diamond Wafering Blades (Diamond, CBN)
• Cutting fluids (cool, lubricate, and clear debris)
• Bond types (resin or rubber) affect cutting speed and blade life.

a. Trojan CT-2300 Manual Table Cut-off Machine

The CT-2300 is a compact, desktop Manual Cut-off Machine, widely used for cutting materials such as PCB boards, semiconductor components, wafer ceramics, quartz glass, and petrographic samples.

• Cutting Wheel Diameter: Ø180 mm
• Maximum Cutting Capacity: Ø30 mm
• Motor Power: 0.9 kW
• Speed Control: Adjustable from 200 to 3000 rpm
• Cutting Modes: Supports both dry and wet cutting

b. Trojan Beta-300 Pro Automatic Cut-off Machine

The Beta-300 Pro is a fully automatic vertical metallographic cutting machine featuring intelligent control, touchscreen operation, laser positioning, and a large worktable. Designed for heavy-duty samples, it offers multiple cutting modes and high repeatability for precise, consistent results.

• Max Cutting Diameter: Ø110 mm
• Cutting Wheel Size: Ø300 mm
• Motor Power: 4 kW – suitable for heavy-duty materials
• Fully Automatic 3-Axis Control (X-Y-Z) with laser positioning for precise, repeatable cuts
• 7" HD Touchscreen – save and customize up to 20 cutting programs
• Pulse Cutting with Auto Speed Adjustment – improves cut quality on hard materials
• Intelligent Cutting Force Adjustment – adapts to material hardness
• Multiple Cutting Modes – handles various sample types
• Quick-Release Vise System – fast and secure sample clamping

2. Specimen Mounting

Mounting stabilizes the specimen for further preparation and protects its edges. It also allows for easier handling and precise orientation during grinding and polishing.

Mounting Resin Types

1. Epoxy Resin: Low shrinkage, high adhesion, excellent chemical resistance
2. Acrylic Resin: Fast curing, good hardness, strong odor
3. Polyester Resin: Water-clear finish, ideal for display mounts

Mounting Equipment

• Mounting Press: Applies heat and pressure for compression mounting
• Accessories: Mounting molds, sample clips, mixing tools, and storage containers

TROJAN MT-1H Mounting Press

The MT-1H is a semi-automatic hot mounting machine with a 7-inch touchscreen and user-friendly interface. It uses hydraulic pressure and supports various thermosetting materials like epoxy, bakelite, and acrylic. Designed for high efficiency and quality, it offers programmable settings, real-time temperature/pressure display, cooling control, and quick sleeve replacement.

3. Grinding and Polishing

This step refines the sample surface to a mirror-like finish for microscopic analysis.

• Grinding removes surface damage and flattens the sample.
• Polishing eliminates fine scratches for high clarity.

Choosing the Right Abrasive Disc

• Hard materials: Prefer diamond abrasives
• Soft materials: Use silicon carbide or alumina

Automatic vs. Manual Metallographic Grinding and Polishing Machines

The decision to use an automatic or manual metallographic grinding and polishing machine depends on factors like sample volume, precision requirements, and budget.

Automatic Machines

• Ideal for high-throughput laboratories
• Offer consistent pressure, speed, and timing
• Reduce operator fatigue and ensure reproducibility

Manual Machines

• Suitable for low-volume or specialized work
• Allow fine control, especially important for delicate samples
• More affordable but require experienced handling

Trojan Alpha-108 Single Disc Grinder & Polisher

The Trojan Alpha-108 is a compact, single-disc grinder & polisher with an 8" (203mm) disc diameter. Ideal for general metallographic prep in low to medium workloads. Its simple design and smaller footprint suit labs with limited space.

Trojan Alpha-208 Double Wheels Grinder & Polisher

The Trojan Alpha-208 offers dual wheels, higher motor power, and advanced features like gesture controls and intelligent overload protection. It’s designed for high-volume labs needing faster, more flexible sample processing.

4. Etching

Etching enhances microstructural features by selectively attacking material surfaces. It reveals grain boundaries, phases, and other characteristics.

Etching Methods:

• Chemical Etching (most common)
• Electrolytic, thermal, plasma, and magnetic etching for specialized applications

5. Microscopy and Image Analysis

Once the specimen is properly prepared, it is examined using an optical microscope, a digital microscope, or a scanning electron microscope (SEM) to evaluate its microstructure.

Dino-Lite AM8917MZT Digital Microscope	Euromex Oxion Inverso Inverted Microscope

6. Hardness Testing

Hardness testing evaluates a material’s resistance to deformation, helping determine tensile strength, wear resistance, and ductility. It’s widely used in quality control and material comparison.

A. Rockwell Hardness (HR)

• Uses a steel ball or spheroconical penetrator
• Measures indentation depth under load
• Fast, widely used for metals

B. Brinell Hardness (BHN)

• Uses a 10 mm steel or tungsten carbide ball with a 3,000 kgf load
• Suitable for coarse-grained materials
• BHN can be correlated to tensile strength (empirically)

KING Portable Brinell Hardness Tester

C. Vickers Hardness (HV)

• Uses a diamond-shaped indenter
• Accurate for all metals, regardless of hardness
• Produces a Vickers Pyramid Number (HV or DPH)

TROJAN Distributor in Singapore

LFC PTE LTD is the authorized distributor of TROJAN Metallographic Equipment in Singapore. Our expert team can assist you in selecting the ideal metallographic equipment to meet your specific measurement needs.

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