1038 Steel: Properties and Key Applications Overview

1038 steel is classified as a medium-carbon alloy steel, primarily composed of iron with a carbon content of approximately 0.38%. This steel grade is known for its excellent strength and hardness, making it suitable for a variety of engineering applications. The primary alloying elements in 1038 steel include manganese, which enhances hardenability and strength, and silicon, which improves deoxidation during steelmaking.

Comprehensive Overview

The inherent properties of 1038 steel include good tensile strength, wear resistance, and the ability to be heat treated for enhanced performance. Its mechanical properties can be further optimized through processes such as quenching and tempering, which allow it to achieve a balance between hardness and ductility.

Advantages of 1038 Steel:
- High Strength and Hardness: Suitable for applications requiring high load-bearing capacity.
- Good Machinability: Can be easily machined into complex shapes.
- Versatile Heat Treatment: Can be tailored to meet specific performance requirements.

Limitations of 1038 Steel:
- Moderate Corrosion Resistance: Not ideal for environments prone to corrosion without protective coatings.
- Weldability Challenges: Requires careful consideration of welding techniques to avoid cracking.

Historically, 1038 steel has been utilized in various applications, including automotive components, machinery parts, and structural applications, due to its favorable mechanical properties and adaptability.

Alternative Names, Standards, and Equivalents

Standard Organization	Designation/Grade	Country/Region of Origin	Notes/Remarks
UNS	G10380	USA	Closest equivalent to AISI 1038
AISI/SAE	1038	USA	Commonly used in North America
ASTM	A29/A29M	USA	General specification for alloy steels
EN	1.0402	Europe	Minor compositional differences
DIN	C38	Germany	Similar properties, but different applications
JIS	S38C	Japan	Comparable but with slight variations in composition

The differences between equivalent grades can affect performance, particularly in terms of hardenability and weldability. For instance, while AISI 1038 and EN 1.0402 are similar, the latter may have slightly different mechanical properties due to variations in manufacturing processes.

Key Properties

Chemical Composition

Element (Symbol and Name)	Percentage Range (%)
C (Carbon)	0.35 - 0.42
Mn (Manganese)	0.60 - 0.90
Si (Silicon)	0.15 - 0.40
P (Phosphorus)	≤ 0.040
S (Sulfur)	≤ 0.050

The primary role of carbon in 1038 steel is to enhance hardness and strength through heat treatment. Manganese contributes to hardenability and improves the steel's toughness, while silicon aids in deoxidation during the steelmaking process.

Mechanical Properties

Property	Condition/Temper	Test Temperature	Typical Value/Range (Metric)	Typical Value/Range (Imperial)	Reference Standard for Test Method
Tensile Strength	Annealed	Room Temp	600 - 700 MPa	87 - 102 ksi	ASTM E8
Yield Strength (0.2% offset)	Annealed	Room Temp	350 - 450 MPa	51 - 65 ksi	ASTM E8
Elongation	Annealed	Room Temp	15 - 20%	15 - 20%	ASTM E8
Hardness (Brinell)	Quenched & Tempered	Room Temp	200 - 250 HB	200 - 250 HB	ASTM E10
Impact Strength	Quenched & Tempered	-20°C (-4°F)	30 - 50 J	22 - 37 ft-lbf	ASTM E23

The combination of high tensile and yield strength makes 1038 steel suitable for applications that require resistance to deformation under load, such as in structural components and machinery parts.

Physical Properties

Property	Condition/Temperature	Value (Metric)	Value (Imperial)
Density	-	7.85 g/cm³	0.284 lb/in³
Melting Point	-	1425 - 1540 °C	2600 - 2800 °F
Thermal Conductivity	20°C	45 W/m·K	31 BTU·in/ft²·h·°F
Specific Heat Capacity	-	0.46 kJ/kg·K	0.11 BTU/lb·°F

The density of 1038 steel contributes to its weight and structural integrity, while its melting point indicates its suitability for high-temperature applications. The thermal conductivity is significant for applications involving heat transfer.

Corrosion Resistance

Corrosive Agent	Concentration (%)	Temperature (°C)	Resistance Rating	Notes
Chlorides	3-5	25-60	Fair	Risk of pitting
Sulfuric Acid	10-20	25-50	Poor	Not recommended
Atmospheric	-	Varies	Fair	Requires protective coating

1038 steel exhibits moderate resistance to corrosion, particularly in chloride environments, where it is susceptible to pitting. Compared to stainless steels, such as 304 or 316, 1038 steel's corrosion resistance is significantly lower, making it less suitable for marine or chemical processing applications.

Heat Resistance

Property/Limit	Temperature (°C)	Temperature (°F)	Remarks
Max Continuous Service Temp	400	752	Suitable for moderate temperatures
Max Intermittent Service Temp	500	932	Short-term exposure only
Scaling Temperature	600	1112	Risk of oxidation beyond this temp

At elevated temperatures, 1038 steel maintains its strength but may experience oxidation if not properly protected. Its performance in high-temperature applications is adequate, but care must be taken to avoid prolonged exposure to extreme conditions.

Fabrication Properties

Weldability

Welding Process	Recommended Filler Metal (AWS Classification)	Typical Shielding Gas/Flux	Notes
MIG	ER70S-6	Argon + CO2	Preheat recommended
TIG	ER70S-2	Argon	Requires post-weld heat treatment
Stick	E7018	-	Good for thicker sections

Weldability of 1038 steel can be challenging due to its carbon content, which may lead to cracking if not properly managed. Preheating and post-weld heat treatment are recommended to mitigate these risks.

Machinability

Machining Parameter	[1038 Steel]	AISI 1212	Notes/Tips
Relative Machinability Index	70	100	Good for general machining
Typical Cutting Speed (Turning)	30-40 m/min	50-60 m/min	Use carbide tools for best results

1038 steel offers good machinability, though it is not as easy to machine as lower carbon steels. Optimal cutting speeds and tooling can enhance performance during machining operations.

Formability

1038 steel can be formed using both cold and hot processes. Cold forming is feasible but may require higher forces due to work hardening. Hot forming is preferred for complex shapes, allowing for better ductility and reduced risk of cracking.

Heat Treatment

Treatment Process	Temperature Range (°C)	Typical Soaking Time	Cooling Method	Primary Purpose / Expected Result
Annealing	600 - 700	1 - 2 hours	Air	Softening, improving ductility
Quenching	800 - 850	30 minutes	Oil/Water	Hardening
Tempering	400 - 600	1 hour	Air	Reducing brittleness

Heat treatment processes significantly alter the microstructure of 1038 steel, enhancing its hardness and strength while allowing for tailored mechanical properties.

Typical Applications and End Uses

Industry/Sector	Specific Application Example	Key Steel Properties Utilized in this Application	Reason for Selection
Automotive	Crankshafts	High strength, wear resistance	Load-bearing components
Machinery	Gears	Toughness, machinability	Complex shapes and durability
Construction	Structural beams	Strength, ductility	Load-bearing structures

Other applications include:
- Manufacturing of fasteners
- Production of axles and shafts
- Use in heavy machinery components

1038 steel is chosen for these applications due to its favorable balance of strength, toughness, and machinability, making it ideal for components that experience high stress.

Important Considerations, Selection Criteria, and Further Insights

Feature/Property	[1038 Steel]	[AISI 4140]	[AISI 1045]	Brief Pro/Con or Trade-off Note
Key Mechanical Property	High strength	Higher toughness	Moderate strength	4140 offers better toughness but lower machinability
Key Corrosion Aspect	Moderate	Fair	Fair	All require protective measures in corrosive environments
Weldability	Moderate	Good	Moderate	4140 is easier to weld than 1038
Machinability	Good	Moderate	Good	4140 is more challenging to machine
Formability	Moderate	Good	Good	4140 has better formability characteristics
Approx. Relative Cost	Moderate	Higher	Lower	1038 is cost-effective for many applications
Typical Availability	Common	Less common	Common	1038 is widely available in various forms

When selecting 1038 steel, considerations include its cost-effectiveness, availability, and suitability for specific applications. While it offers a good balance of properties, alternatives like AISI 4140 may be preferred in applications requiring higher toughness or better weldability.

In summary, 1038 steel is a versatile medium-carbon alloy steel that provides a strong combination of mechanical properties, making it suitable for a wide range of engineering applications. Its performance can be optimized through heat treatment and careful fabrication processes, ensuring it meets the demands of various industries.