Pipe Materials and Classification


🔷 Pipe Materials Classification

1. Metals
   ├─ Ferrous
   │  ├─ Iron
   │  │  ├─ Wrought Iron
   │  │  └─ Cast Iron (Gray, Ductile, White, Malleable)
   │  └─ Steel
   │     ├─ High Alloy (e.g., Stainless Steel)
   │     ├─ Medium Alloy (e.g., Cr-Mo)
   │     └─ Carbon Steel
   │         ├─ High Carbon (>0.6%)
   │         ├─ Medium Carbon (~0.3%)
   │         └─ Low Carbon (<0.3%)
   └─ Non-Ferrous (Nickel, Copper, Aluminum alloys)

2. Non-Metals
   ├─ Non-Plastic (Concrete, Glass)
   └─ Plastic (Thermoplastics, Thermosets, Fiber Reinforced)

🔶 Cast Iron Overview

Wrought Iron: Tough, ductile, corrosion-resistant (low carbon <0.05%)

Cast Iron Types:

Gray: Graphite flakes, easy to machine (ASTM A48)

Ductile: Graphite nodules, shock resistant (ASTM A395)

White: Cementite-rich, brittle

Malleable: Annealed white iron, tough yet ductile (ASTM A47)

🔷 Carbon Steel Insights

Composed of <2% C, with elements like Si, Mn, S, P

Common Standards: ASTM A106, ASTM A53, API 5L

Alloy Elements:

Element Role

C (Carbon) Strength & hardness, but affects ductility
Mn Deoxidizer, improves strength
Si Improves castability
Cr Corrosion resistance, hardness
Mo High-temp strength, creep resistance
Ni Fracture toughness, austenitic structure at high %
Cu Atmospheric corrosion resistance
V Grain refinement, hydrogen resistance

🔶 Essential Characteristics of Pipe Materials

1. Chemical – Elements, impurities, alloy content

2. Physical – Density, conductivity, thermal expansion

3. Microstructure – Grain size, phase composition

4. Mechanical – Yield, ultimate strength, toughness, ductility

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