An Overview of What is ASTM A105?
ASTM A105 is a standard specification developed by ASTM International for carbon steel forgings. It covers forged carbon steel components that are primarily used for piping systems in pressure systems at ambient and higher-temperature service.
It is widely used for flanges, fittings, valves, and other pressure-containing parts.
Key Highlights:
| Aspect | Details |
|---|---|
| Scope | Forged carbon steel piping components |
| Product Forms | Flanges, forged fittings, valves, and other piping parts |
| Material Type | Carbon Steel |
| Forging Method | Open die, closed die, or ring forging |
| Service Temperature Range | Suitable for ambient- and high-temperature service |
| Heat Treatment | Normally supplied in normalized, normalized and tempered, or quenched and tempered condition for certain sizes |
| Surface Finish | Machined or as-forged surfaces |
| Testing Required | Tensile testing, hardness testing, chemical composition testing |
Mechanical Properties:
| Property | Requirement |
|---|---|
| Minimum Yield Strength | 36,000 psi (250 MPa) |
| Minimum Tensile Strength | 70,000 psi (485 MPa) |
| Elongation | ~22% minimum in 2 inches |
| Hardness Limit | Max 187 HBW (Brinell Hardness) without heat treatment |
(For thicker parts or special service, normalization or heat treatment may be required to refine the grain structure and improve performance.)
Common Applications:
- Flanges (weld neck, slip-on, blind, etc.)
- Forged fittings (elbows, tees, reducers)
- Valves bodies and bonnets
- Pressure vessels
- High-pressure piping systems
Important Notes:
- ASTM A105 material is limited to components up to 4 inches (100 mm) in nominal thickness (for piping parts) unless specifically treated.
- For low-temperature service, ASTM A350 LF2 (not A105) is preferred because A105 doesn’t guarantee low-temperature toughness unless specified.
- It must meet chemical composition limits for carbon, manganese, phosphorus, sulfur, silicon, and others.
- No special impact test is required unless specified in the purchase order.
Chemical Composition (Typical Limits):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.35% |
| Manganese (Mn) | 0.60–1.05% |
| Phosphorus (P) | ≤ 0.035% |
| Sulfur (S) | ≤ 0.040% |
| Silicon (Si) | 0.10–0.35% |
Quick Comparison to Similar Specs:
| Specification | Key Difference |
|---|---|
| ASTM A105 | For general carbon steel forgings |
| ASTM A350 LF2 | For low-temperature carbon steel forgings |
| ASTM A182 F11/F22 | For alloy steel (used at high temperature) |
ASTM A53 vs ASTM A105 – Quick Comparison Sheet
| Feature | ASTM A53 | ASTM A105 |
|---|---|---|
| Scope | Standard for carbon steel pipes (seamless and welded) | Standard for carbon steel forgings (flanges, fittings, valves, etc.) |
| Form | Pipe (seamless, ERW, or furnace-welded) | Forged parts (flanges, fittings, valves, etc.) |
| Grades | Grade A and Grade B | Single grade (no division into A/B) |
| Types | Type F (furnace butt-welded), Type E (ERW), Type S (seamless) | Forged only |
| Typical Applications | Transport of fluids: water, gas, steam, air | Piping system components under pressure: flanges, fittings, valves |
| Material | Carbon Steel | Carbon Steel (higher carbon compared to piping steels) |
| Manufacturing Method | Hot forming (pipe rolling, welding) | Forging (open-die, closed-die, or ring forging) |
| Strength | – Grade A: ~48 ksi Tensile – Grade B: ~60 ksi Tensile | – Minimum Tensile Strength: ~70 ksi – Higher strength than A53 |
| Pressure Suitability | Medium pressures | High pressures |
| Temperature Suitability | Ambient and moderately elevated temperatures | Ambient and higher temperatures (normal service); not ideal for low temperatures unless specified |
| Surface Options | Bare, black-painted, or hot-dip galvanized | Machined or as-forged finish |
| Heat Treatment | Usually not heat-treated (unless specified) | May be normalized, normalized and tempered, or quenched and tempered |
| Testing Requirements | Hydrostatic test, non-destructive electric test, tensile test | Tensile, hardness tests; chemical composition checks |
| Common Standards Used With | API 5L, ASTM A106, ASTM A252 | ASME B16.5 (for flanges), ASME B16.11 (for fittings), etc. |
| Low-Temperature Service | Not specifically designed for low temperatures | Not ideal unless normalized; A350 LF2 is preferred for low temp |
| Primary Focus | Fluid transportation (pipes) | Pressure-retaining parts (flanges, fittings) |
Quick Summary:
- ASTM A53: Think pipes for moving fluids (low-medium pressure).
- ASTM A105: Think forged flanges and fittings to connect piping systems (higher pressure).