SAE 1045 Steel – Chemical Composition, Properties and Uses

by AMC

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Posted on December 08, 2023 at 12:57 PM

SAE 1045, a widely utilized medium-carbon steel, stands out as a preferred choice globally. Renowned for its exceptional blend of high strength, weldability, and impact resistance, this common steel grade offers versatility and reliability. Moreover, its affordability enhances its popularity among consumers, making AISI 1045 a practical and cost-effective option for various applications.

Before making a purchase, it's crucial to learn about the SAE 1045 steel to ensure you acquire the right product for your needs. This article provides an in-depth exploration of SAE/AISI 1045 steel, covering its hot-rolled, normalized, and cold-rolled variants, and discuss some of the key characteristics to aid in making informed decisions about this versatile steel grade.

What does 1045 mean in steel?

• AISI or SAE Identification: Recognized by the American Iron and Steel Institute (A.I.S.I.) and the Society of Automotive Engineers (S.A.E.) as AISI or SAE 1045.
• Carbon Content: The first digit '1' in 1045 signifies that the steel is primarily composed of carbon.
• Alloy Components: The second digit '0' indicates that the steel has no significant alloying elements, making it a non-alloy or plain carbon steel.
• Carbon Percentage: The final two digits, '45,' specify the carbon content of the steel. In this case, 1045 steel contains 0.45 percent carbon.

SAE 1045 Carbon Steel Chemical Composition

Grade	C	Si	Mn	P	S
1045	0.43-0.50	0.15-0.35	0.60-0.90	≤0.04	≤0.05

SAE 1045 Steel Physical Property

Density, g/cm3

7.86
Melting point,℃	1433
Specific heat capacity，(0~100℃),J/(kg.k)	577.78(200℃)
Linear expansion coefficient,10^-6/k	0~100℃
	11.7
Poisson's ratio	0.269
Elastic Modulus,Mpa	209000
Shear modulus,Mpa	82300
Thermal conductivity,W/(m.K)	46.89(200℃)
Resistivity，10^-8 Ω.m	32.0(200℃)

SAE 1045 Mechanical Property

Tensile,Mpa	Yield,Mpa	Elongation,%	Reduction,%	Charpy Impact,J	Hardness,HBW
≥532	≥280	≥32	≥49	≥60	160-200

SAE 1045 Thermal Properties

Properties	Metric	Imperial
Thermal conductivity	51.9 W/mK	360 BTU in/hr.ft2.°F
Thermal expansion co-efficient (@0.000-100°C/32-212°F)	11.2 µm/m°C	6.22 µm/m°C

SAE 1045 Steel Heat Treatment

Normalizing Temperature: 830-880℃
Holding Time: The duration depends on the workpiece size and loading capacity. In our experience, shorter holding times are suitable for smaller SAE 1045 steel sizes. As the size increases, the holding time may be extended. However, an excessively prolonged holding time can result in coarse grains and material overburning, adversely affecting material properties. Cooling Method: Air cooling is recommended, and rapid cooling can be achieved by misting water. Caution should be exercised to avoid overly fast cooling, as it may lead to material cracking.

Rationale: Normalizing is a crucial heat treatment process for SAE 1045 steel.

• For general-purpose parts, normalizing can serve as the final heat treatment, ensuring the material meets specified properties.
• As a preparatory step for the final quenching and tempering heat treatment, normalizing helps refine grain structure and homogenize the material, establishing a favorable foundation for subsequent heat treatment processes.

Balancing the duration of holding time and cooling methods is essential to achieving the desired material properties without compromising structural integrity during the heat treatment of SAE 1045 steel.

SAE 1045 Steel Annealing

Purpose of Annealing Heat Treatment: The primary objective of annealing for SAE 1045 steel, based on our experience, is typically to soften surface hardness for improved machinability.

Annealing Temperature: The annealing temperature for SAE 1045 steel is typically maintained within the range of 820-840°C.

Holding Time: A sufficient holding time at the annealing temperature is essential to achieve the desired softening effect. The material is then allowed to cool to room temperature within the furnace.

Measured Surface Hardness: Post-annealing, the measured surface hardness of SAE 1045 steel usually falls below 200 HBW (Brinell Hardness), significantly facilitating subsequent processing and machining operations.

SAE 1045 Steel Quenching & Tempering (QT)

Application Scenario: Quenching and tempering (QT) heat treatment is recommended for SAE 1045 steel when it is utilized in critical structural components such as connecting rods, gears, bolts, and shafts operating under alternating loads. This process enhances the overall mechanical properties of SAE 1045 steel, ensuring it meets stringent performance requirements.

Quenching Parameters:

Quench Temperature: 820-840°C

Quench Medium: Water/Oil

Quenching Hardness: 55-60HRC

Tempering Parameters:

Tempering Temperature: 500-540°C

Tempering Hardness: 28-32HRC

Rationale:

Critical Components: Quenching and tempering are employed when normalizing alone cannot meet the performance requirements, particularly for critical structural parts subjected to alternating loads.

Comprehensive Mechanical Properties: The quenching process imparts high hardness to the material, enhancing its wear resistance, while tempering at a controlled temperature subsequently reduces brittleness and optimizes toughness, resulting in a balanced set of mechanical properties.

Tempering Benefits: The tempering stage is crucial for adjusting hardness, relieving residual stresses, and achieving the desired combination of hardness and toughness for the specific application

SAE 1045 Steel Tempering Temperature Vs Hardness

Grade	Quenching		Tempering Temperature,ºC
	Temperature,ºC	Hardness,HRC	150ºC	200ºC	300ºC	400ºC	500ºC	550ºC	600ºC
SAE 1045	840ºC	58-59	58	55	50	41	33	26	22

SAE1045 Steel Supply Form & Size & Tolerance

Surface Finish	Black-Forged	Black-Rolled	Turned	Grinding	Polished	Peeled	Cold Drawn
Tolerance	(0，+5mm)	(0，+1mm)	(0，+3mm)	Best h9	Best h11	Best H11	Best H11

Where to buy 1045 Steel?

Discover the convenience of shopping for AISI 1045 steel at amardeepsteel.com, where you have the flexibility to order any quantity, at any time, on any day. Benefit from some of the most competitive pricing available online.

Our inventory includes:

1045 Turned, Ground & Polished Round Bars: Precision-engineered for superior performance.

Hot-Rolled and Cold-Rolled Round Bars: Providing versatility for various applications.

Plate and Flat Bars: Available, with sizing options to meet your specific needs.

For a seamless experience, contact us, and our friendly customer support representatives will be delighted to assist you with your metal request. At GetMetals.com, we strive to make your AISI 1045 steel procurement hassle-free and cost-effective.

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