ASTM A860/A860M is the standard specification by ASTM International covering wrought high-strength ferritic steel butt-welding fittings of seamless and electric fusion-welded construction. The fittings are designed for high-pressure transmission service and intended to be used with pipe manufactured to API 5L. The latest edition is A860/A860M-24 (2024).
Zhengzhou Huitong (HT Pipe) supplies ASTM A860 / SA-860 compliant wrought butt-weld fittings (elbows, tees, reducers, caps, stub ends) in all standard WPHY grades with full Mill Test Certificates (MTC) per EN 10204 3.1, Charpy V-Notch impact test reports, and complete traceability per ASTM A960.
1. Standard Scope & Designation
ASTM A860/A860M covers wrought high-strength ferritic steel butt-welding fittings for high-pressure transmission service. Fittings may be made from seamless pipe, electric fusion-welded pipe (with filler metal), or plate. The steel shall be completely killed and fine-grained. Fittings shall be suitable for welding to pipe and fittings of matching yield strength.
| Attribute |
Inch-Pound (A860) |
SI / Metric (A860M) |
| Issuing Body |
ASTM International |
ASTM International |
| Unit System |
Inch-Pound (ksi) |
SI (MPa) |
| Grade Designation |
WPHY-42 through WPHY-80 |
WPHY-290 through WPHY-550 |
| Dimensional Standards |
ASME B16.9, MSS SP-75 |
ASME B16.9, MSS SP-75 |
| Latest Edition |
A860/A860M-24 (2024) |
A860/A860M-24 (2024) |
| Governing General Req. |
ASTM A960 / A960M |
ASTM A960 / A960M |
Scope Statement (ASTM A860-24): "This specification covers wrought high-strength ferritic steel butt-welding fittings of seamless and electric-fusion welded construction, manufactured with a welding process that adds filler metal. These fittings are intended for high-pressure transmission service and are designed to be used with pipe manufactured to API 5L or comparable specifications."
2. WPHY Grades Covered by ASTM A860
ASTM A860 covers WPHSY (Wrought High Yield) grades corresponding to API 5L pipe grades. Each WPHY grade has a minimum yield strength matching the API 5L grade designation. All grades require Charpy V-Notch impact testing at -29C (-20F) and mandatory heat treatment. The material shall be completely killed and fine-grained.
| WPHS Grade |
API 5L |
Yield min ksi (MPa) |
Tensile min ksi (MPa) |
Typical Application |
| WPHY-42 |
X42 |
42 (290) |
60 (415) |
Standard high-pressure gathering lines |
| WPHY-46 |
X46 |
46 (315) |
63 (435) |
Moderate high-pressure transmission |
| WPHY-52 |
X52 |
52 (360) |
66 (455) |
Main transmission pipelines, onshore |
| WPHY-56 |
X56 |
56 (385) |
71 (490) |
High-pressure trunk lines |
| WPHY-60 |
X60 |
60 (415) |
75 (515) |
Most common grade; LNG, offshore |
| WPHY-65 |
X65 |
65 (450) |
77 (530) |
High-pressure offshore and onshore |
| WPHY-70 |
X70 |
70 (485) |
82 (565) |
Deepwater subsea, heavy-duty |
| WPHY-80 |
X80 |
80 (550) |
95 (655) |
Extreme high-pressure, critical |
WPHY-60 is the most widely used ASTM A860 grade. It provides an optimal balance of strength (60 ksi / 415 MPa min yield), toughness (CVN >= 27 J @ -29C), weldability (CE <= 0.42%), and cost-effectiveness. WPHY-60 fittings are specified for LNG terminals, offshore platforms, and long-distance high-pressure transmission pipelines worldwide.
3. Chemical Composition Requirements
Values are maximum unless shown as a range. The steel shall be completely killed and fine-grained. Carbon Equivalent (CE) formula: CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 shall not exceed 0.42%. Vacuum carbon-deoxidized steel (per Supplementary Requirement S3) shall have Si <= 0.10% max (heat) / 0.12% max (product).
| El. |
WPHY-42/46/52 |
WPHY-56 |
WPHY-60 |
WPHY-65 |
WPHY-70 |
WPHY-80 |
| C% |
0.25 |
0.22 |
0.20 |
0.20 |
0.20 |
0.20 |
| Mn% |
1.00-1.45 |
1.00-1.50 |
1.00-1.45 |
1.00-1.50 |
1.00-1.50 |
1.00-1.50 |
| P% |
0.030 |
0.030 |
0.030 |
0.030 |
0.030 |
0.030 |
| S% |
0.010 |
0.010 |
0.010 |
0.010 |
0.010 |
0.010 |
| Si% |
0.15-0.40 |
0.15-0.40 |
0.15-0.40 |
0.15-0.40 |
0.15-0.40 |
0.15-0.40 |
| Ni% |
0.50 |
0.50 |
0.50 |
0.50 |
0.50 |
0.50 |
| Cr% |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
0.30 |
| Mo% |
0.25 |
0.25 |
0.25 |
0.25 |
0.25 |
0.25 |
| Cu% |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
0.35 |
| Ti% |
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
| V% |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
0.10 |
| Cb% |
0.04 |
0.04 |
0.04 |
0.04 |
0.04 |
0.04 |
| V+Cb% |
0.12 |
0.12 |
0.12 |
0.12 |
0.12 |
0.12 |
Key Notes: CE formula: CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 shall not exceed 0.42% for weldability. Residual elements: Ni + Cr + Mo + Cu shall not exceed 1.0% combined. Vacuum carbon deoxidation (SR S3): Si <= 0.10% heat / 0.12% product.
4. Mechanical Property Requirements
All values are minimum requirements after required heat treatment. Testing per ASTM A370. Elongation applies to standard round specimen (4D gauge length). Hardness: maximum 22 HRC (235 HBW) per A960. Yield strength determined by 0.2% offset method.
| Grade |
Yield min ksi (MPa) |
Tensile min ksi (MPa) |
Elong. % |
Notes |
| WPHY-42 |
42 (290) |
60 (415) |
23 |
Lowest strength grade |
| WPHY-46 |
46 (315) |
63 (435) |
22 |
|
| WPHY-52 |
52 (360) |
66 (455) |
21 |
|
| WPHY-56 |
56 (385) |
71 (490) |
20 |
|
| WPHY-60 |
60 (415) |
75 (515) |
20 |
Most common |
| WPHY-65 |
65 (450) |
77 (530) |
20 |
|
| WPHY-70 |
70 (485) |
82 (565) |
18 |
|
| WPHY-80 |
80 (550) |
95 (655) |
18 |
Highest strength |
5. Charpy V-Notch Impact Test Requirements
All ASTM A860 WPHY fittings require mandatory Charpy V-Notch (CVN) impact testing at the standard test temperature of -29C (-20F). For electric fusion-welded fittings, both the base metal and the weld metal shall be impact tested. Testing per ASTM E23 on standard 10x10 mm specimens (subsize per ASTM A370 for thin sections).
| Parameter |
Requirement |
| Test Temperature |
-29C (-20F) |
| Min. Avg. Energy (3 specimens) |
20 J (15 ft·lbf) |
| Min. Single Specimen Energy |
14 J (10 ft·lbf) |
| Specimen Size |
10 x 10 mm (subsize allowed per A370) |
| Weld Metal Testing |
Required for electric fusion-welded fittings |
| Test Standard |
ASTM E23 |
Weld Metal Impact: For fittings made by the electric fusion-welding process, one set of Charpy impact tests shall be performed on both the base metal and the weld metal. The weld metal test verifies that the deposited filler metal maintains adequate toughness at the test temperature.
6. Heat Treatment Requirements
All ASTM A860 WPHY fittings shall be heat treated. The steel shall be completely killed and fine-grained. Heat treatment must be performed after all forming and welding operations. Fittings formed above the transformation temperature or made by the electric fusion-welding process shall be cooled to below the critical temperature before heat treatment.
| Heat Treatment |
Applicability |
Notes |
| Normalizing (N) |
All WPHY grades |
Refines grain, optimizes toughness |
| Quenching + Tempering (Q+T) |
All WPHY grades |
Higher strength grades preferred |
| Stress Relieving (SR) |
All WPHY grades |
Post-weld SR for welded fittings |
| Normalizing + Tempering (N+T) |
All WPHY grades |
Combined N + SR |
ASTM A960/A960M Compliance: Heat treatment shall be performed in accordance with ASTM A960/A960M. The heat treatment lot definition, qualification requirements, and temperature control tolerances are governed by A960.
7. Testing & Inspection Requirements
| Test / Inspection |
Requirement |
Standard |
| Chemical Analysis (Heat) |
One per heat; all elements per grade limits |
ASTM A960 |
| Tensile Test (Room Temp.) |
One per lot; yield, tensile, elongation |
ASTM A370 |
| Charpy V-Notch Impact Test |
MANDATORY; base metal + weld metal |
ASTM E23 |
| Hardness Test |
Max 22 HRC (235 HBW) |
ASTM E10 / E18 |
| Radiographic Examination |
Full length of all welds |
ASTM E94 / ASME V Art. 2 |
| Hydrostatic Test |
Per dimensional standard |
ASME B16.9 / MSS SP-75 |
| PMI (Positive Material ID) |
Verify chemistry at delivery |
ASTM E572 |
| Visual & Dimensional |
Per ASME B16.9 or MSS SP-75 tolerances |
ASME B16.9 |
8. Product Types & Dimensional Standards
ASTM A860 fittings are manufactured to dimensional standards ASME B16.9 (standard sizes) and MSS SP-75 (large sizes). Butt-welding fittings differing from ASME B16.9 shall be furnished in accordance with Supplementary Requirement S58 of ASTM A960.
| Fitting Type |
Size Range |
Dimensional Standard |
| Elbows (90°, 45°) |
1/2\" to 48\" NPS |
ASME B16.9 / MSS SP-75 |
| Tees (Equal & Reducing) |
1/2\" to 48\" NPS |
ASME B16.9 / MSS SP-75 |
| Reducers (Concentric & Eccentric) |
1/2\" to 48\" NPS |
ASME B16.9 / MSS SP-75 |
| Caps |
1/2\" to 48\" NPS |
ASME B16.9 / MSS SP-75 |
| Stub Ends |
1/2\" to 48\" NPS |
ASME B16.9 Type A/B |
| Short Radius Elbows |
1/2\" to 24\" NPS |
ASME B16.28 |
| Dimensional Standard |
Size Range |
Schedule Range |
| ASME B16.9 |
1/2\" to 14\" NPS |
SCH 10, 20, 30, 40, 60, 80, 100, 120, 140, 160, XXS |
| MSS SP-75 |
14\" to 48\" NPS |
SCH STD, XS, 80, 120, 160, XXS |
9. Related Standards & Companion Specifications
| Standard |
Scope |
Relationship to A860 |
| ASTM A960 / A960M |
Common requirements for pipe fittings |
Primary governing general spec |
| API 5L |
Specification for line pipe |
Compatible pipe material |
| ASME B16.9 |
Factory-made wrought BW fittings (1/2\"-14\") |
Mandatory dimensional standard |
| MSS SP-75 |
High-test wrought fittings (14\"-48\") |
Large size dimensional standard |
| ASME B16.28 |
Wrought short radius elbows |
Short radius fitting dimensions |
| ASTM A370 |
Mechanical testing of steel products |
Required test method |
| ASTM E23 |
Notch bar impact testing |
Impact test method |
| ASME Section IX |
Welding procedure qualifications |
Welding qualification required |
10. A860 vs A234 vs A420 vs A694 — Butt-Weld Fitting Specifications Compared
| Criteria |
ASTM A860 |
ASTM A234 |
ASTM A420 |
ASTM A694 |
| Product |
BW Fittings |
BW Fittings |
BW Fittings |
Flanges & Forgings |
| Steel Type |
HSLA Ferritic |
Carbon & Alloy |
Carbon & Alloy (Low-Temp) |
Carbon & HSLA |
| Grades |
WPHY 42-80 |
WP 1-91, WPR 1-91 |
WPL 3, 6, 9 |
F42-F70 |
| Impact Test |
Mandatory |
Not Required |
Mandatory |
Not Required |
| Max Yield (ksi) |
80 (WPHY-80) |
30-65 |
30-35 |
70 |
| Heat Treatment |
Mandatory |
Required for alloy |
Mandatory |
Mandatory |
| Primary Use |
Hi-pressure transmission |
Process plant piping |
Low-temp service |
HP flanges |
Grade Selection: Choose A860 WPHY-60 for high-pressure transmission pipelines (X60 pipe). Choose A420 WPL6 for low-temperature service fittings. Choose A234 WPB/WPC for general process plant piping at moderate temperatures. Choose A694 F60 for forged flanges on transmission pipelines.
11. How to Order — Required Information
| No. |
Item |
Requirement / Example |
| 1 |
Specification |
ASTM A860/A860M or ASME SA-860 |
| 2 |
Grade |
e.g., WPHY-60 (most common), WPHY-65, WPHY-70 |
| 3 |
Fitting Type |
Elbow 90°, Elbow 45°, Tee, Reducer, Cap, Stub End |
| 4 |
NPS & Schedule |
e.g., NPS 12 SCH 40, NPS 24 SCH XS, NPS 6 x 4 Reducer |
| 5 |
Dimensional Standard |
ASME B16.9 (NPS 1/2 to 14\") or MSS SP-75 (NPS 14 to 48\") |
| 6 |
Construction |
Seamless or Electric Fusion-Welded (EFW) |
| 7 |
Heat Treatment |
Normalized (N), Q+T, N+T, or Stress Relieved (SR) |
| 8 |
Supplementary Requirements |
S3 (Vacuum deoxidation), S58 (Non-B16.9 dimensions), S60 (Hydrostatic test) |
| 9 |
Certification |
EN 10204 3.1 CMTR with CVN test results |
| 10 |
Quantity |
Pieces (pcs); with tolerance if applicable |
Download ASTM A860 / A860M Standard (PDF)
The official ASTM A860/A860M-24 (2024) PDF is available from our HT Pipe Download Center. The document includes full mechanical property requirements, chemical composition limits, mandatory Charpy impact test Table, heat treatment requirements, and supplementary requirements per ASTM A960/A960M.
Go to Download Center | Request MTC / Quotation
12. Frequently Asked Questions
Q: What is ASTM A860 WPHY-60 used for?
ASTM A860 WPHY-60 is used for wrought butt-weld fittings (elbows, tees, reducers, caps) in high-pressure oil and gas transmission pipelines. WPHY-60 corresponds to API 5L X60 pipe and is specified for long-distance transmission pipelines, LNG terminal piping, offshore platform pipelines, and high-pressure gathering systems. It is the most common ASTM A860 grade due to its optimal balance of strength (60 ksi / 415 MPa yield), toughness (CVN >= 20 J @ -29C), weldability (CE <= 0.42%), and cost.
Q: What is the difference between ASME B16.9 and MSS SP-75 for A860 fittings?
ASME B16.9 covers factory-made wrought butt-welding fittings from NPS 1/2 to NPS 14. MSS SP-75 covers high-test wrought fittings from NPS 14 to NPS 48. Both standards define dimensions (OD, wall thickness, center-to-end dimensions, bevels), but MSS SP-75 has a different schedule numbering system (STD, XS, 80, 120, 160, XXS) compared to B16.9 (SCH 10 through XXS). For A860 WPHY fittings larger than NPS 14, MSS SP-75 dimensions apply.
Q: What impact test is required for ASTM A860 electric fusion-welded fittings?
For A860 fittings made by the electric fusion-welding process, one set of Charpy V-Notch impact tests shall be performed on both the base metal AND the weld metal. The test temperature is -29C (-20F). The minimum average absorbed energy for 3 specimens is 20 J (15 ft·lbf); no single specimen may be less than 14 J (10 ft·lbf). This dual testing requirement ensures that both the parent steel and the deposited filler metal maintain adequate toughness in service.
Q: Can ASTM A860 WPHY-60 fittings be welded to API 5L X60 pipe?
Yes. ASTM A860 WPHY fittings are specifically designed to be compatible with API 5L line pipe of the corresponding grade. WPHY-60 fittings are intended for use with API 5L X60 pipe. Both the fitting and pipe have matching yield strength (60 ksi / 415 MPa min) and compatible chemistry (CE <= 0.42%). Welding procedures must be qualified per ASME Section IX, and the filler metal selection should match the mechanical properties of the base metal.
Q: What is the carbon equivalent (CE) requirement for ASTM A860?
ASTM A860 requires CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 to not exceed 0.42% for weldability. This strict CE limit ensures that WPHY fittings can be successfully welded in the field without preheating or post-weld heat treatment in most cases. Vacuum carbon-deoxidized steel (per Supplementary Requirement S3) further restricts Si to <= 0.10% (heat) / <= 0.12% (product) for enhanced toughness and cleanliness.
Q: Why does ASTM A860 require mandatory impact testing while ASTM A234 does not?
ASTM A860 fittings are specified for high-pressure transmission pipelines where cyclic loading, stress concentrations at fittings, and potential brittle fracture are critical concerns. The mandatory Charpy V-Notch impact test at -29C (-20F) verifies that the material has adequate notch toughness to resist fracture under these conditions. ASTM A234 fittings are typically used in process plant piping where lower stress levels and more predictable loading reduce fracture risk, so impact testing is not required unless specified by the purchaser.
Request a Quote — ASTM A860 WPHY Butt-Weld Fittings
Zhengzhou Huitong (HT Pipe) supplies ASTM A860 / SA-860 compliant wrought butt-weld fittings in all standard WPHY grades (WPHY-42, WPHY-52, WPHY-60, WPHY-65, WPHY-70, WPHY-80) with full EN 10204 3.1 CMTRs, Charpy impact test reports, and competitive lead times from our manufacturing facility in China.
