ASTM A519

Product introduction

1. Material Overview

ASTM A519 is the standard specification for Seamless Carbon and Alloy Steel Mechanical Tubing. Unlike pressure piping standards (e.g., A53, A106), A519 tubing is designed for mechanical and structural applications where precise dimensions, strength, and machinability are critical. It is commonly used in parts requiring further fabrication like machining, grinding, or heat treatment.

2. Chemical Composition by Grade

Grade (UNS No.)	C (%)	Mn (%)	P ≤ (%)	S ≤ (%)	Si (%)	Other Alloys	Common Analog
1020 (G10200)	0.18-0.23	0.30-0.60	0.040	0.050	0.10-0.30	-	Low-C Steel
1025 (G10250)	0.22-0.28	0.30-0.60	0.040	0.050	0.10-0.30	-	Low-C Steel
1035 (G10350)	0.32-0.38	0.60-0.90	0.040	0.050	0.10-0.30	-	Med-C Steel
1045 (G10450)	0.43-0.50	0.60-0.90	0.040	0.050	0.10-0.30	-	Med-C Steel
4130 (G41300)	0.28-0.33	0.40-0.60	0.035	0.040	0.15-0.35	Cr: 0.80-1.10, Mo: 0.15-0.25	Chromoly
4140 (G41400)	0.38-0.43	0.75-1.00	0.035	0.040	0.15-0.35	Cr: 0.80-1.10, Mo: 0.15-0.25	Chromoly
8620 (G86200)	0.18-0.23	0.70-0.90	0.035	0.040	0.15-0.35	Cr: 0.40-0.60, Ni: 0.40-0.70, Mo: 0.15-0.25	Case-Hardening

3. Mechanical Properties (Typical, Cold Drawn Condition)

Property	1020	1045	4130	4140	8620
Tensile Strength	70-85 ksi (480-585 MPa)	90-110 ksi (620-760 MPa)	90-110 ksi (620-760 MPa)	95-120 ksi (655-825 MPa)	75-90 ksi (515-620 MPa)
Yield Strength	60-70 ksi (415-485 MPa)	70-85 ksi (480-585 MPa)	70-85 ksi (480-585 MPa)	80-95 ksi (550-655 MPa)	55-65 ksi (380-450 MPa)
Elongation in 2"	15-25%	12-18%	15-20%	12-18%	18-25%
Hardness (Brinell)	150-180 HB	200-230 HB	200-230 HB	220-260 HB	170-200 HB
Machinability	Excellent (100% ref)*	Good (70%)	Good (75%)	Fair (65%)	Excellent (90%)

Note: Properties are for cold drawn (CD) condition. Hot finished (HF) properties are lower. Machinability rated vs. 1212 steel as 100%.

4. Graphical Strength Comparison (Cold Drawn Condition)

Tensile and Yield Strength Range by Grade
↑ Strength (ksi)
|
|130 ┼                                    ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ [4140 Tensile]
|    |                                    |
|120 ┼                         ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
|    |                         |          |
|110 ┼             ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ [1045/4130 Tensile]
|    |             |          |          |
|100 ┼             ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
|    |             |          |          |
|90  ┼▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ [8620 Tensile]
|    |▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓|
|80  ┼▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ [4140 Yield]
|    |▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓|
|70  ┼▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ [1020 Tensile]
|    |▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ [1045/4130 Yield]
|60  ┼▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ [1020 Yield]
|    |▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓|
|50  ┼▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ [8620 Yield]
|    |_______________________________________________________________
     1020       1045       4130       4140       8620
     
▓▓▓▓▓ = Tensile Strength Range   ░░░░░ = Yield Strength Range

5. Key Characteristics

Manufacturing Process: Exclusively seamless (no welded tube), produced via hot extrusion or piercing and cold drawing.
Dimensional Precision: Tighter OD/ID tolerances and smoother surface finish than structural or pressure pipe.
Condition: Typically supplied as cold drawn (CD) for higher strength and better finish, or hot finished (HF).
Heat Treatment Response: Excellent, especially alloy grades (4130, 4140, 8620) can be quenched and tempered to significantly higher strengths.
Primary Use: A component requiring secondary machining or fabrication, not for fluid conveyance under pressure.

6. Common Applications by Grade

Grade	Typical Applications
1020/1025	Shafts, pins, rollers, bushings, low-stress structural parts.
1035/1045	Higher-strength shafts, gears, spindles, bolts, hydraulic cylinders.
4130	Aircraft engine mounts, bicycle frames, race car roll cages, high-strength structural tubing.
4140	High-strength axles, bolts, connecting rods, tool holders, die blocks.
8620	Gears, pinions, camshafts, and other case-hardened components requiring a tough core and hard surface.

7. Comparison with Similar Tubing Standards

Property	ASTM A519 (Mechanical Tubing)	ASTM A53 (Pipe)	ASTM A500 (Structural Tubing)
Primary Purpose	Machined components, precision parts	Pressure conveyance, plumbing	Structural support, frames
Manufacture	Seamless only	Seamless or welded	Welded or seamless (Gr. D)
Dimensional Tolerance	Very tight (mechanical specs)	Standard pipe schedules	Structural tolerances
Surface Finish	Smooth (cold drawn)	Standard mill finish	Standard mill finish
Common Grades	1020, 1045, 4130, 4140	A, B	A, B, C, D
Pressure Rating	Not intended/rated for pressure	Rated for pressure service	Not for pressure

8. Fabrication & Processing Notes

Machinability: Carbon grades (1020, 1045) offer excellent machinability. Alloy steels (41xx, 86xx) require slower speeds/feeds.
Welding: Low-carbon grades (1020) weld easily. Medium-carbon (1045) and alloy grades require preheat, post-heat, and low-hydrogen electrodes.
Heat Treatment: Grades like 1045, 4130, and 4140 are routinely heat treated (quench & temper) after machining to achieve desired strength/hardness.
Cold Drawing: The CD process increases strength, improves surface finish, and tightens tolerances compared to hot-finished (HF) material.

9. Limitations and Important Notes

NOT A PRESSURE STANDARD: A519 tubing is not intended for pressure containment. Do not substitute it for pressure pipe (A53, A106) or pressure tubing (A179, A213) in pressure systems.
Condition Matters: Properties vary significantly between hot-finished (HF, as-rolled) and cold-drawn (CD, stress-relieved) conditions. Always specify.
Alloy Grades: Require specific thermal handling during welding and machining to avoid cracking or loss of properties.
Cost: Generally more expensive than standard pipe or structural tubing due to the seamless manufacturing process and tighter tolerances.

Note: ASTM A519 is a broad specification covering many grades. The specific chemical and mechanical requirements should be verified from the latest ASTM A519 standard for the ordered grade and condition. For critical applications, material certifications (mill test reports) are essential.

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