ASTM A519 Grade 1045 Seamless Tube Supplier

Specification Chemical Composition Mechanical Properties

ASTM A519 Grade 1045 Specification

ASTM International has developed the ASTM A519 specification for seamless carbon and alloy steel mechanical tubing. The ASTM A519 Grade 1045 is a medium-carbon steel tube with the chemical and mechanical property requirements as listed in the table below. The ASME specification is ASME SA519 Grade 1045 which has the same chemical and mechanical requirements. Product may be procured to either standard.

Feature	Specification Details
Standard	ASTM A519
Grade	1045
UNS Number	G10450
SAE / AISI Equivalent	SAE 1045 / AISI 1045
ASME Equivalent	ASME SA519 1045
OD Range	6.35 mm to 406.4 mm (0.25 in to 16.00 in)
Wall Thickness Range	0.89 mm to 50.8 mm (0.035 in to 2.00 in)
Length	Random or cut to length as per requirement
Supply Conditions	Cold Drawn Seamless (CDS), Hot Finished Seamless (HFS), Normalised, Quenched and Tempered (Q+T)
End Finish	Plain end, bevelled end, threaded end

ASTM A519 Grade 1045 Chemical Composition

Grade 1045 derives its name from its nominal carbon content of approximately 0.45%. The elevated carbon percentage relative to lower grades such as 1020 and 1035 is the primary reason for its superior hardenability and quench and temper response. Manganese at 0.60 to 0.90% acts as a solid-solution strengthener and improves through-hardening during heat treatment. Phosphorus and sulfur are held to controlled maximums to preserve toughness and weldability.

Element	C	Mn	P (max)	S (max)	Si
Percentage (%)	0.43 to 0.50	0.60 to 0.90	0.040	0.050	0.15 to 0.35

ASTM A519 Grade 1045 Mechanical Properties

The table below is the complete condition matrix for ASTM A519 Grade 1045 seamless mechanical tubing. All strength values are shown in both MPa (metric) and ksi (imperial) to support global procurement and design verification. Select the supply condition that matches your application load requirement and heat treatment specification.

Condition	Yield MPa	Yield ksi	UTS MPa	UTS ksi	Elongation %	Hardness
Cold Drawn Seamless (CDS)	530	77	625	91	12	20 HRC
Hot Finished Seamless (HFS)	415	60	565	82	16	16 HRC
Normalised	450	65	585	85	16	17 HRC
Quenched and Tempered (Q+T)	620	90	760	110	14	24 HRC

Note: Values above are typical guaranteed minimums per ASTM A519. Actual test certificates (mill test reports) will be furnished with every shipment. For Cold Drawn Seamless Mechanical Tubing the CDS condition delivers the highest yield and hardness values without further heat treatment. For Hot Finished Seamless Mechanical Tubing the HFS condition provides improved ductility and elongation, which is preferred for applications requiring subsequent forming or machining.

ASTM A519 Grade 1045 vs 1040 Comparison

The most common grade selection decision in this carbon range is between 1040 and 1045. Both grades share the same manganese window and are governed by the same ASTM A519 specification. The difference lies in the carbon range: 1045 carries a higher minimum and maximum carbon content, which translates directly into higher yield strength, higher tensile strength, and a stronger response to quench and temper heat treatment. For full technical data on the lower grade, see the ASTM A519 1040 Seamless Tube product page.

Summary: Choose 1040 when strength requirements can be met without the full heat treatment cycle and cost savings on raw material are a factor. Choose 1045 when the application demands higher hardness in the CDS condition, a higher guaranteed minimum UTS, or a more predictable and consistent response to quench and temper. Components such as gears, hydraulic cylinder barrels, and heavy-duty shafts consistently favour 1045 for this reason.

ASTM A519 Grade 1045 vs 4130 Chromoly: When to Upgrade

When design loads exceed what Grade 1045 in Q+T condition can sustain, or when weight reduction is a project constraint, the next upgrade path is chromium-molybdenum alloy steel. ASTM A519 4130 Seamless Tube offers significantly higher yield strength in the normalised and Q+T condition, better low-temperature toughness, and superior fatigue performance in cyclic load applications. The trade-off is a higher base material cost and a mandatory preheat requirement above 93 degrees Celsius for wall thicknesses greater than 6 mm during welding. For applications such as hydraulic cylinders operating at moderate pressures, 1045 remains the preferred and more cost-effective choice. For aerospace sub-structures, motorsport chassis, and high-pressure hydraulic manifolds, 4130 is the correct specification.

ASTM A519 Grade 1045 Supply Conditions and Dimensional Availability

USA Piping Solution stocks and supplies ASTM A519 Grade 1045 seamless mechanical tubing across the dimensional range shown below. CDS tubes are produced by cold drawing a hot-rolled hollow to final dimensions, resulting in tighter tolerances, a superior surface finish, and higher as-drawn mechanical properties. HFS tubes are produced in the hot rolling mill and offer wider OD and wall ranges with good straightness and concentricity. Both CDS and HFS can be supplied in Normalised or Quenched and Tempered condition on request with full heat treatment certification.

Tolerances comply with ASTM A519 Table 1 for OD and wall thickness. Lengths are available in random mill lengths or cut to exact customer specification. Special requirements including ovality testing, hydrostatic testing, ultrasonic examination, and magnetic particle inspection are available on written request with appropriate lead time.

ASTM A519 Grade 1045 Seamless Tube Applications

Grade 1045 is one of the most widely specified medium-carbon grades in mechanical engineering. Its combination of machinability in the annealed and normalised condition and its excellent response to heat treatment makes it suitable for a broad range of precision machined and structural components.

• Drive shafts and transmission shafts in automotive and heavy equipment
• Hydraulic cylinder barrels and piston rods in medium-pressure fluid power systems
• Gear blanks, sprocket hubs, and ring gears for industrial machinery
• Precision guide pins, connecting rods, and machine tool spindles
• Structural tubing in mining, agricultural, and construction equipment frames
• Tooling mandrels, rolling mill arbors, and press tooling components

For reference articles covering the broader alloy steel product range, visit the Guide to Alloy Steel Pipes and the Types of Alloy Steel Classification blog posts on this site. Both have been updated to cross-reference the Grade 1045 product page for editorial authority.

ASTM A519 Grade 1045 is part of the broader Carbon Steel Pipes and Tubes product range available from USA Piping Solution. The carbon steel range covers a complete spectrum of specifications from low-carbon weldable grades through to the medium-carbon and alloy steel mechanical tubing products described on this page.

Other ASTM A519 Grades Available from USA Piping Solution

The ASTM A519 grade cluster covers low-carbon, medium-carbon, and chromoly alloy grades for the full range of mechanical tubing applications. Every grade listed below is available with the same supply conditions, certification, and dimensional range as Grade 1045. Select the grade page that matches your application requirement or contact us to discuss multi-grade procurement on a single purchase order.

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