ASTM A618/A618M-21 is a standard issued by the American Society for Testing and Materials (US-ASTM) and is classified under the 23.040.10 iron and steel pipe category in the International Standard Classification. This standard deals primarily with requirements and specifications for high-strength structural pipes.
ASTM A618 high-strength structural pipe has excellent mechanical properties and welding performance to meet the needs of various high-strength structural applications. They are often used in bridges, buildings, highways, oil and gas transmission and other fields, where steel pipes are required to have excellent load-bearing capacity and corrosion resistance.
| ASTM A618 Chemical Requirements | ||||||||
| Composition, % | Grade Ia | Grade Ib | Grade II | Grade III | ||||
| Heat | Product | Heat | Product | Heat | Product | Heat | Product | |
| Carbon, max | 0.15 | 0.18 | 0.20 | . . . | 0.22 | 0.26 | 0.23A | 0.27A |
| Manganese | 1.00 max | 1.04 max | 1.35 max | 1.40 max | 0.85–1.25 | 1.30 max | 1.35 maxA | 1.40 maxA |
| Phosphorus, max | 0.15 | 0.16 | 0.025 | 0.035 | 0.025 | 0.035 | 0.025 | 0.035 |
| Sulfur, max | 0.025 | 0.045 | 0.025 | 0.035 | 0.025 | 0.035 | 0.025 | 0.035 |
| Silicon, max | . . . | . . . | . . . | . . . | 0.30 | 0.33 | 0.30 | 0.35 |
| Copper, min | 0.20 | 0.18 | 0.20B | 0.18B | 0.20 | 0.18 | . . . | . . . |
| Vanadium, min | . . . | . . . | . . . | . . . | 0.02 | 0.01 | 0.02C | 0.01 |
| A For each reduction of 0.01 % C below the specified carbon maximum, an increase of 0.05 % manganese above the specified maximum will be permitted up to 1.45 % for the heat analysis and up to 1.50 % for the product analysis.
B If chromium and silicon contents are each 0.50 % min, then the copper minimums do not apply. C For Grade III, columbium may be used in conformance with the following limits: 0.005 %, min (heat) and 0.004 %, min (product). |
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| ASTM A618 Tensile Requirements | ||||||
| Grades la, lb, and ll | Grade lll | |||||
|
Walls 3⁄4 in. [19.0 mm] and Under |
Walls over 3⁄4 to 11⁄2 in. [19.0 to 38.0mm], incl |
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| Tensile strength, min, ksi [MPa]A Yield strength, min, ksi [MPa]A Elongation in 2 in. or 50 mm, min, % Elongation in 8 in. or 200 mm, min, % |
70 50 22 19 |
[485] [345] |
67 46 22 18 |
[460] [315] |
65 50 20 18 |
[450] [345] |
| A For Grade II, when the material is normalized, the minimum yield strength and minimum tensile strength required shall be reduced by 5 ksi [35 MPa] | ||||||
