1137 Steel: Properties and Key Applications
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Table Of Content
Table Of Content
1137 Steel is classified as a medium-carbon alloy steel, primarily known for its excellent combination of strength, toughness, and wear resistance. The primary alloying elements in 1137 steel include carbon (C), manganese (Mn), and silicon (Si), which significantly influence its mechanical properties and performance in various applications.
Comprehensive Overview
1137 steel typically contains a carbon content of approximately 0.30% to 0.40%, which contributes to its strength and hardness. Manganese, usually present in the range of 0.60% to 0.90%, enhances hardenability and improves tensile strength. Silicon, often around 0.15% to 0.40%, serves to improve the steel's deoxidation during the melting process and contributes to its overall strength.
The most significant characteristics of 1137 steel include its good machinability, high strength-to-weight ratio, and excellent wear resistance. These properties make it suitable for various engineering applications, particularly in the automotive and manufacturing sectors.
Advantages of 1137 Steel:
- High Strength: Offers good tensile and yield strength, making it suitable for load-bearing applications.
- Wear Resistance: Excellent resistance to wear, making it ideal for components subjected to friction.
- Machinability: Generally easy to machine, allowing for efficient manufacturing processes.
Limitations of 1137 Steel:
- Corrosion Resistance: Moderate resistance to corrosion, which may necessitate protective coatings in certain environments.
- Weldability: While weldable, it may require preheating and post-weld heat treatment to avoid cracking.
Historically, 1137 steel has been utilized in various applications, including gears, shafts, and other components requiring high strength and durability. Its market position is solid, with a consistent demand in industries that prioritize performance and reliability.
Alternative Names, Standards, and Equivalents
| Standard Organization | Designation/Grade | Country/Region of Origin | Notes/Remarks |
|---|---|---|---|
| UNS | G11370 | USA | Closest equivalent to AISI 1137 |
| AISI/SAE | 1137 | USA | Medium-carbon alloy steel |
| ASTM | A108 | USA | Standard specification for cold-finished carbon steel bars |
| EN | 1.1181 | Europe | Equivalent grade with minor compositional differences |
| JIS | S45C | Japan | Similar properties, but with different carbon content limits |
The table above highlights various standards and equivalents for 1137 steel. Notably, while grades like S45C and 1.1181 may appear equivalent, they can differ in specific alloying elements and mechanical properties, which can affect performance in critical applications.
Key Properties
Chemical Composition
| Element (Symbol and Name) | Percentage Range (%) |
|---|---|
| C (Carbon) | 0.30 - 0.40 |
| Mn (Manganese) | 0.60 - 0.90 |
| Si (Silicon) | 0.15 - 0.40 |
| P (Phosphorus) | ≤ 0.04 |
| S (Sulfur) | ≤ 0.05 |
The primary role of the key alloying elements in 1137 steel is as follows:
- Carbon (C): Increases hardness and strength through solid solution strengthening and the formation of carbides.
- Manganese (Mn): Enhances hardenability and tensile strength, while also improving the steel's resistance to wear.
- Silicon (Si): Acts as a deoxidizer during steel production and contributes to the overall strength of the steel.
Mechanical Properties
| Property | Condition/Temper | Typical Value/Range (Metric) | Typical Value/Range (Imperial) | Reference Standard for Test Method |
|---|---|---|---|---|
| Tensile Strength | Annealed | 600 - 800 MPa | 87 - 116 ksi | ASTM E8 |
| Yield Strength (0.2% offset) | Annealed | 350 - 500 MPa | 51 - 73 ksi | ASTM E8 |
| Elongation | Annealed | 15 - 20% | 15 - 20% | ASTM E8 |
| Hardness (Rockwell C) | Annealed | 20 - 30 HRC | 20 - 30 HRC | ASTM E18 |
| Impact Strength | -40°C | 30 - 50 J | 22 - 37 ft-lbf | ASTM E23 |
The combination of these mechanical properties makes 1137 steel particularly suitable for applications involving dynamic loading and structural integrity requirements, such as in automotive components and machinery parts.
Physical Properties
| Property | Condition/Temperature | Value (Metric) | Value (Imperial) |
|---|---|---|---|
| Density | - | 7.85 g/cm³ | 0.284 lb/in³ |
| Melting Point/Range | - | 1425 - 1540 °C | 2600 - 2800 °F |
| Thermal Conductivity | 20°C | 45 W/m·K | 31 BTU·in/h·ft²·°F |
| Specific Heat Capacity | 20°C | 460 J/kg·K | 0.11 BTU/lb·°F |
| Electrical Resistivity | 20°C | 0.0006 Ω·m | 0.00002 Ω·in |
Key physical properties such as density and thermal conductivity are significant for applications where weight and heat dissipation are critical. The density of 1137 steel allows for robust designs without excessive weight, while its thermal conductivity ensures efficient heat transfer in applications like engine components.
Corrosion Resistance
| Corrosive Agent | Concentration (%) | Temperature (°C) | Resistance Rating | Notes |
|---|---|---|---|---|
| Chlorides | 3-10 | 20-60 | Fair | Risk of pitting |
| Sulfuric Acid | 10-30 | 20-40 | Poor | Not recommended |
| Sodium Hydroxide | 5-20 | 20-60 | Fair | Susceptible to SCC |
1137 steel exhibits moderate corrosion resistance, particularly in environments with chlorides and alkaline substances. It is susceptible to pitting corrosion and stress corrosion cracking (SCC) in certain conditions. Compared to grades like AISI 4140, which has better corrosion resistance due to its higher chromium content, 1137 steel may require protective coatings or treatments in corrosive environments.
Heat Resistance
| Property/Limit | Temperature (°C) | Temperature (°F) | Remarks |
|---|---|---|---|
| Max Continuous Service Temp | 400 | 752 | Suitable for moderate heat |
| Max Intermittent Service Temp | 500 | 932 | Short-term exposure only |
| Scaling Temperature | 600 | 1112 | Risk of oxidation beyond this temp |
At elevated temperatures, 1137 steel maintains its strength but may begin to lose hardness and toughness. Oxidation can become a concern, particularly above 600 °C, necessitating careful consideration in high-temperature applications.
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 | Post-weld heat treatment needed |
1137 steel is weldable but requires preheating to minimize the risk of cracking. Post-weld heat treatment is also recommended to relieve residual stresses and improve toughness.
Machinability
| Machining Parameter | [1137 Steel] | AISI 1212 | Notes/Tips |
|---|---|---|---|
| Relative Machinability Index | 70 | 100 | Good machinability, but harder than 1212 |
| Typical Cutting Speed (Turning) | 30 m/min | 50 m/min | Use high-speed steel tools |
Optimal machining conditions include using sharp tools and appropriate cutting speeds to achieve the best surface finish and tool life.
Formability
1137 steel exhibits good formability, suitable for both cold and hot forming processes. However, care must be taken with bend radii to avoid cracking, especially in cold forming applications.
Heat Treatment
| Treatment Process | Temperature Range (°C) | Typical Soaking Time | Cooling Method | Primary Purpose / Expected Result |
|---|---|---|---|---|
| Annealing | 600 - 700 | 1 - 2 hours | Air | Softening, improved ductility |
| Quenching + Tempering | 850 - 900 | 30 minutes | Oil | Increased hardness and strength |
During heat treatment, 1137 steel undergoes metallurgical transformations that enhance its mechanical properties. Quenching followed by tempering can significantly increase hardness while maintaining toughness.
Typical Applications and End Uses
| Industry/Sector | Specific Application Example | Key Steel Properties Utilized in this Application | Reason for Selection |
|---|---|---|---|
| Automotive | Gears | High strength, wear resistance | Essential for durability |
| Manufacturing | Shafts | Toughness, machinability | Critical for performance |
| Aerospace | Structural components | Strength-to-weight ratio | Important for efficiency |
Other applications include:
- Machine components
- Fasteners
- Tooling
1137 steel is often chosen for its balance of strength and machinability, making it ideal for components that require both durability and ease of manufacturing.
Important Considerations, Selection Criteria, and Further Insights
| Feature/Property | [1137 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 is harder to machine |
| Key Corrosion Aspect | Moderate | Good | Fair | 4140 has better corrosion resistance due to chromium |
| Weldability | Moderate | Good | Fair | 4140 may require more preheat |
| Machinability | Good | Fair | Excellent | 1045 is easier to machine |
| Approx. Relative Cost | Moderate | Higher | Lower | Cost considerations vary by application |
| Typical Availability | Common | Less common | Very common | 1045 is widely available |
When selecting 1137 steel, considerations include its mechanical properties, cost-effectiveness, and availability. While it offers a good balance of strength and machinability, alternatives like AISI 4140 may be preferred in applications requiring higher toughness or corrosion resistance. Additionally, 1137 steel's moderate weldability and machinability make it suitable for various manufacturing processes, though care must be taken to avoid issues during fabrication.