ASTM A105/A105M is the standard specification by ASTM International covering forged carbon steel piping components including flanges, fittings, valve bodies, and couplings for pressure-temperature service in piping systems. It is the most widely used material specification for carbon steel forgings in the oil, gas, power, and process industries. The companion specification ASME SA-105 adopts identical requirements for ASME BPVC compliance.
HT PIPE supplies ASTM A105 / SA-105 compliant forged carbon steel fittings and flanges with full Mill Test Certificates (MTC) per EN 10204 3.1.
1. Standard Scope & Designation
ASTM A105/A105M covers forged carbon steel piping components for pressure service at ambient and elevated temperatures:
| Product Category |
Products Covered |
Size Range |
Dimensional Standard |
| Forged Flanges |
Weld neck, slip-on, socket-weld, threaded, blind, lap joint |
NPS 1/2 – NPS 24 |
ASME B16.5 |
| Forged Fittings |
Elbows, tees, reducers, caps, couplings, laterals |
NPS 1/8 – NPS 4 |
ASME B16.11 |
| Valve Bodies & Parts |
Bodies, bonnets, stems, yokes for steel valves |
All sizes |
Per applicable valve spec |
| Piping Components |
Bends, pup pieces, collars, wyes |
NPS 1/2 – NPS 12 |
Per purchase order |
Scope Statement (ASTM A105-22): "This specification covers forged carbon steel piping components for ambient and high-temperature pressure systems. The forgings shall be made by open die, press, or closed die forging methods and shall be heat treated. Unless otherwise specified, all forgings shall be furnished in the annealed, normalized, or normalized and tempered condition."
| Designation |
Issuing Body |
Unit System |
Latest Edition |
| ASTM A105 |
ASTM International |
Inch-Pound |
A105/A105M-22 |
| ASTM A105M |
ASTM International |
SI (Metric) |
A105/A105M-22 |
| ASME SA-105 |
ASME (BPVC Sec. II Part A) |
Both |
2023 Edition |
2. Grades & Classes of ASTM A105
ASTM A105 has two main product classes differentiated by heat treatment:
2.1 Product Classes
| Class |
Heat Treatment |
Yield Strength |
Typical Use |
| A105 |
Annealed or normalized (producer's option) |
min. 250 MPa (36 ksi) |
General pressure piping, ambient temp |
| A105N |
Normalized (mandatory) |
min. 275 MPa (40 ksi) |
Higher toughness, elevated temp, code piping |
2.2 Supplementary Requirements (When Specified)
| SR |
Description |
Requirement |
| S1 |
Charpy V-notch impact testing |
CVN avg. 18 J (13 ft-lbf) min at test temp |
| S2 |
Low-temperature Charpy testing |
CVN at -46°C (or other specified temp) |
| S3 |
Drop weight test (Pellini) |
NDT per ASTM E208 |
| S5 |
Killed steel requirement |
Al ≥ 0.025% or specified deoxidization |
| S6 |
Coarse grain practice |
Al grain size 5 or coarser per ASTM E112 |
2.3 Related Carbon Steel Specifications
| Spec |
Product Form |
Heat Treatment |
Key Difference from A105 |
| A350 LF2 |
Forgings |
Normalized + tempered |
For cryogenic service to -50°C |
| A216 WCB |
Castings (not forgings) |
Annealed or N+T |
Castings vs forgings; not interchangeable |
| A234 WPB |
Butt-weld fittings |
Normalized or N+T |
BW fittings; similar composition to A105 |
| A106 Gr.B |
Seamless pipe |
As-reduced or normalized |
Pipe vs forgings; compatible for piping systems |
3. Chemical Composition — ASTM A105 Table 1
Heat analysis. Values are maximum unless shown as a range. For product analysis, refer to A105 Table 2 for tolerances.
| Element |
Grade A105 |
Grade A105N |
Notes |
| Carbon (C) |
≤ 0.35% |
≤ 0.30% |
Lower C in N-grade for improved weldability |
| Manganese (Mn) |
0.60 – 1.05% |
0.60 – 1.05% |
— |
| Phosphorus (P) |
≤ 0.035% |
≤ 0.035% |
Product analysis ≤ 0.040% |
| Sulfur (S) |
≤ 0.040% |
≤ 0.040% |
Product analysis ≤ 0.050% |
| Silicon (Si) |
0.10 – 0.35% |
0.10 – 0.35% |
— |
| Copper (Cu) |
≤ 0.40% |
≤ 0.40% |
— |
| Nickel (Ni) |
≤ 0.40% |
≤ 0.40% |
— |
| Chromium (Cr) |
≤ 0.30% |
≤ 0.30% |
— |
| Molybdenum (Mo) |
≤ 0.12% |
≤ 0.12% |
— |
| Vanadium (V) |
≤ 0.03% |
≤ 0.03% |
— |
Note on Weldability: A105 has carbon equivalent (CE) up to ~0.60% for A105 and ~0.52% for A105N. Preheating to 100–150°C is recommended for heavy sections (>50 mm) and for A105 forgings in general. Post-weld heat treatment (PWHT) at 600–650°C is recommended after welding to restore toughness in the HAZ.
4. Mechanical Property Requirements (ASTM A105 Table 3)
All values are minimum requirements. Per ASTM A105/A105M-22.
| Property |
A105 |
A105N |
| Tensile Strength |
485 MPa (70 ksi) |
485 MPa (70 ksi) |
| Yield Strength (0.2% offset) |
250 MPa (36 ksi) |
275 MPa (40 ksi) |
| Elongation in 2 in. (50 mm) |
22% |
22% |
| Reduction of Area |
30% |
30% |
| Brinell Hardness (max) |
187 HB / 89 HRB |
187 HB / 89 HRB |
For forgings >635 mm (25 in.) in section thickness, refer to ASTM A105 Annex A1 for adjusted requirements.
Temperature Limits: A105 is limited to -29°C to +427°C (-20°F to +800°F). Below -29°C, supplementary impact testing (S1/S2) is required. For cryogenic service below -50°C, use A350 LF2. Above 427°C, use chrome-moly forgings (ASTM A182 F1, F5, F9).
5. Heat Treatment Requirements
| Condition |
Heat Treatment |
Typical Cooling |
Applicable To |
| Annealed |
Full anneal: heat to 870–925°C |
Furnace cool |
A105 (producer's option) |
| Normalized |
Normalize: heat to 900–955°C |
Air cool in still air |
A105 (producer's option) or A105N |
| Normalized + Tempered |
Normalize + temper at 590–680°C |
Air cool after tempering |
Heavy sections (>50 mm) for improved toughness |
Heat treatment shall be performed after final forging operations. All heat treatment must be recorded on the MTR.
6. Testing & Inspection Requirements
| Test |
Requirement |
Reference Standard |
| Chemical Analysis (Heat) |
One per heat; all elements per Table 1 |
ASTM A105 Table 1 |
| Tensile Test (Longitudinal) |
One per heat per heat treatment lot |
ASTM A370 |
| Hardness Test |
Brinell or Rockwell; one per lot |
ASTM E10 / E18 |
| Charpy Impact (CVN) |
Per Supplementary Requirement S1/S2 when specified |
ASTM E23 |
| Microstructure |
No internal imperfections; quality level per A788 |
ASTM A788 |
| Hydrostatic Test |
Flanges: 1.5× design pressure (B16.5) or seat test per purchase order |
ASME B16.5 |
| Visual & Dimensional |
Per B16.5 (flanges) or B16.11 (fittings) |
ASME B16.5 / B16.11 |
7. Dimensional Standards for ASTM A105 Products
| Product |
Dimensional Standard |
Size / Pressure Class |
Face / End Types |
| Forged Steel Flanges |
ASME B16.5 |
NPS 1/2 – NPS 24; Class 150–2500 |
RF, FF, RTJ, SW, THD |
| Socket-Weld Fittings |
ASME B16.11 |
NPS 1/8 – NPS 4; Class 2000/3000/6000/9000 |
Socket weld ends |
| Threaded Fittings |
ASME B16.11 |
NPS 1/8 – NPS 4; Class 2000/3000/6000/9000 |
NPT threaded ends |
| BW Fittings (Referenced) |
ASTM A234 WPB (not A105) |
NPS 1/2 – NPS 48 |
Beveled ends (BW) |
RF = Raised Face; FF = Flat Face; RTJ = Ring Type Joint; SW = Socket Weld; THD = Threaded. Note: Butt-weld fittings use ASTM A234 WPB, not A105 — they have a similar carbon steel composition but are formed by bending pipe/plate rather than forging.
8. Industries & Applications
| Industry |
Why A105 |
Typical Components |
| Power Generation (Steam) |
Cost-effective, good high-temp strength |
Boiler flanges, steam header fittings, turbine bypass |
| Oil & Gas Pipelines |
Widely available, Code-approved |
Wellhead flanges, pipe rack fittings, valve bodies |
| Refinery & Petrochemical |
Versatile carbon steel for moderate temps |
Process piping flanges, manifold fittings, couplings |
| HVAC & District Heating |
Economical for large quantities |
Condensate return lines, heating medium systems |
| Water & Wastewater |
Low cost, easy fabrication |
Pumping station flanges, tee fittings, reducer |
| Shipbuilding |
Naval-grade forgings for marine systems |
Engine room piping, ballast system fittings |
9. A105 vs A350 LF2 vs A216 WCB — Carbon Steel Comparison
| Criteria |
ASTM A105 / A105N |
ASTM A350 LF2 |
ASTM A216 WCB |
| Product Form |
Forgings |
Forgings |
Castings |
| Min. Tensile |
485 MPa (70 ksi) |
485 MPa (70 ksi) |
485 MPa (70 ksi) |
| Min. Yield |
250 / 275 MPa (36 / 40 ksi) |
250 MPa (36 ksi) |
250 MPa (36 ksi) |
| Max. Carbon |
0.35 / 0.30% |
0.30% |
0.30% |
| Heat Treatment |
Annealed or Normalized |
N+T (mandatory) |
Annealed or N+T |
| Min. Temp |
-29°C (no impact) / -46°C (with S2) |
-50°C (with impact) |
-29°C (no impact) |
| Max. Temp |
427°C |
427°C |
425°C |
| Typical Use |
General pressure piping |
Cryogenic & low-temp service |
Valve bodies, pump casings |
Important: A216 WCB is a casting, not a forging. WCB fittings are castings, not forgings. Using WCB castings where A105 forgings are specified is a common industry mistake. Forgings (A105) have better mechanical properties and structural integrity than castings due to grain flow from the forging process.
10. Related Standards
| Standard |
Scope |
Relationship to A105 |
| ASME B16.5 |
Pipe Flanges & Flanged Fittings NPS 1/2 – 24 |
Dimensional standard for A105 flanges |
| ASME B16.11 |
Forged Fittings, SW & Threaded |
Dimensional standard for A105 fittings |
| ASTM A350 LF2 |
Forged Low-Temp Carbon Steel Pipe Components |
Cryogenic alternative to A105 |
| ASTM A234 WPB |
Piping Fittings of Wrought Carbon Steel (BW) |
BW fittings; not forging, but compatible |
| ASTM A216 WCB |
Carbon Steel Castings for Valves & Flanges |
Castings — different from A105 forgings |
| ASTM A106 Gr.B |
Seamless Carbon Steel Pipe for High-Temp |
Compatible pipe spec for A105 flanges/fittings |
| ASTM A182 F1 / F5 / F9 |
Alloy Steel Forgings (Cr-Mo grades) |
For temps above 427°C or aggressive media |
11. How to Order — Required Information
| No. |
Item |
Requirement / Example |
| 1 |
Specification |
ASTM A105 / A105N / ASME SA-105 |
| 2 |
Product Type |
Weld neck flange / elbow / tee / coupling |
| 3 |
Size / Pressure Class |
e.g., NPS 6, Class 300 (flange) or NPS 2, Sch 6000 (fitting) |
| 4 |
End Connection |
Weld neck / slip-on / socket weld / threaded / BW bevel |
| 5 |
Face Type |
RF (raised face), FF (flat face), RTJ (ring joint) |
| 6 |
Supplementary Tests |
Impact test (S1/S2), killed steel (S5), grain size (S6) |
| 7 |
Certification |
EN 10204 3.1 Certified Mill Test Report |
| 8 |
Quantity |
Pieces, sets, or weight (kg / MT) |
12. Frequently Asked Questions
Q: What is ASTM A105?
ASTM A105/A105M is the standard specification for forged carbon steel piping components including flanges, fittings, valve bodies, and couplings. It covers products for pressure-temperature service from -29°C to +427°C in ASME B31.1, B31.3, and BPVC piping systems. The companion specification ASME SA-105 adopts identical requirements for Code compliance.
Q: A105 vs A105N — which to choose?
A105N (normalized) is preferred for ASME Code piping applications because normalization provides superior toughness and more uniform microstructure, particularly for heavy-section forgings. The normalized condition also gives a higher minimum yield strength (40 ksi vs 36 ksi). For ambient-temperature, non-code applications, A105 (annealed) is acceptable and typically more economical.
Q: What are the mechanical properties of ASTM A105?
ASTM A105: minimum tensile strength 485 MPa (70 ksi), minimum yield strength 250 MPa (36 ksi), elongation min. 22% in 50 mm, reduction of area min. 30%, hardness max. 187 HB / 89 HRB. A105N increases yield to 275 MPa (40 ksi).
Q: Can ASTM A105 be welded?
Yes. A105 has a carbon equivalent (CE) of up to ~0.60% (A105) or ~0.52% (A105N), so preheating to 100–150°C is recommended for heavy sections (>50 mm wall or heavy flanges). Use AWS E7018 or E7018-1 electrodes for MMA welding. Post-weld heat treatment (PWHT) at 600–650°C for 1 hour per 25 mm thickness is recommended to restore HAZ toughness, especially for A105N or Code-stamped components.
Q: Can A105 be used at cryogenic temperatures?
A105 is limited to -29°C (-20°F) without impact testing. For service below -29°C, impact testing per Supplementary Requirement S1 (CVN 18 J at test temperature) or S2 (at -46°C) is required. For cryogenic service below -50°C, use ASTM A350 LF2 forgings instead, which are specifically designed for low-temperature service with mandatory impact testing.
Q: Is ASTM A105 the same as ASME SA-105?
Technically identical in chemistry and mechanical properties. ASME SA-105 is ASTM A105 adopted into ASME BPVC Section II Part A. SA-105 additionally requires Certified Material Test Reports (CMTR) with full traceability and authorized inspection for ASME Code-stamped pressure equipment. Most A105 forgings are dual-certified A105/SA-105 at no additional cost.
Request a Quote — ASTM A105 Forged Carbon Steel Fittings & Flanges
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