Metallurgical Analysis Skill

Purpose

The Metallurgical Analysis skill provides specialized capabilities for characterizing metallic materials through metallographic techniques, enabling systematic evaluation of microstructure, grain size, phase distribution, and inclusion content per industry standards.

Capabilities

• Metallographic preparation protocol selection
• Etching reagent selection for different alloys
• Grain size measurement (ASTM E112, intercept method)
• Phase fraction quantification (point count, image analysis)
• Inclusion rating (ASTM E45)
• Banding and segregation assessment
• Prior austenite grain boundary revelation
• Weld microstructure evaluation (HAZ mapping)

Usage Guidelines

Sample Preparation

1. Sectioning

   • Select appropriate cutting method (abrasive, EDM, precision saw)
   • Minimize heat input to prevent microstructural changes
   • Identify orientation relative to processing direction

2. Mounting

   • Choose mount type (hot compression, cold setting)
   • Add conductive filler for SEM/EBSD samples
   • Consider edge retention requirements

3. Grinding and Polishing

   • Follow systematic grit progression (120 to 1200 to diamond)
   • Use appropriate lubricant and rotation direction
   • Verify scratch-free surface before etching

Etching Selection

Alloy System	Etchant	Purpose
Carbon steels	2% Nital	General microstructure
Stainless steel	Vilella's	Martensitic structures
Aluminum	Keller's	Grain boundaries, precipitates
Titanium	Kroll's	Alpha-beta microstructure
Copper	FeCl3/HCl	Grain boundaries
Nickel superalloys	Glyceregia	Gamma prime, carbides

Grain Size Measurement

1. ASTM E112 Methods

   • Comparison method: Match to standard charts
   • Planimetric method: Count grains in known area
   • Intercept method: Count grain boundary intersections

2. Calculation

   • Apply magnification correction
   • Use minimum 5 fields for statistical validity
   • Report ASTM grain size number with standard deviation

3. Special Cases

   • Duplex structures: Report both phases separately
   • Elongated grains: Measure aspect ratio
   • Prior austenite: Use specific etchants (picric acid based)

Inclusion Rating (ASTM E45)

1. Method Selection

   • Method A: Worst field rating
   • Method D: Quantitative measurement
   • Specify inclusion type (A, B, C, D sulfides, oxides)

2. Reporting

   • Include severity (thin, heavy) and length
   • Note distribution (random, stringer, cluster)
   • Compare to specification limits

Process Integration

• MS-002: Electron Microscopy Characterization
• MS-017: Root Cause Failure Analysis

Input Schema

{
  "sample_id": "string",
  "alloy_system": "steel|aluminum|titanium|copper|nickel",
  "alloy_grade": "string",
  "analysis_type": "grain_size|phase_fraction|inclusion|weld_eval",
  "magnification": "number",
  "etchant_used": "string"
}

Output Schema

{
  "sample_id": "string",
  "grain_size": {
    "astm_number": "number",
    "average_diameter": "number (microns)",
    "standard_deviation": "number",
    "method": "string"
  },
  "phase_fractions": [
    {
      "phase": "string",
      "fraction": "number (percent)",
      "morphology": "string"
    }
  ],
  "inclusion_rating": {
    "method": "string",
    "type_a": "number",
    "type_b": "number",
    "type_c": "number",
    "type_d": "number"
  },
  "observations": "string"
}

Best Practices

1. Document complete preparation procedure for reproducibility
2. Use consistent magnification within a comparative study
3. Apply appropriate etching time - under-etched is better than over-etched
4. Verify grain boundaries are fully revealed before measurement
5. Use image analysis software for quantitative phase measurements
6. Include representative micrographs in reports

Integration Points

• Connects with Electron Microscopy for high-resolution analysis
• Feeds into Failure Analysis for metallographic investigation
• Supports Mechanical Testing for structure-property correlation
• Integrates with Heat Treatment Optimization for process development