86L20 Steel: Properties and Key Applications
Share
Table Of Content
Table Of Content
86L20 Steel is a low-alloy steel grade primarily classified as a medium-carbon alloy steel. It is characterized by its specific composition, which includes significant amounts of carbon, manganese, and chromium. The alloying elements in 86L20 contribute to its mechanical properties, enhancing its strength, toughness, and wear resistance.
This steel grade is known for its excellent machinability and weldability, making it a popular choice in various engineering applications. Its primary characteristics include good tensile strength, moderate hardness, and excellent ductility, which allow it to withstand significant mechanical stress without failure.
Advantages and Limitations
Advantages:
- High Strength-to-Weight Ratio: 86L20 offers a favorable balance of strength and weight, making it suitable for applications where weight reduction is critical.
- Good Machinability: This steel can be easily machined, allowing for efficient production processes.
- Weldability: It can be welded using standard techniques, which is advantageous for fabrication.
Limitations:
- Corrosion Resistance: Compared to stainless steels, 86L20 has limited resistance to corrosion, making it less suitable for harsh environments.
- Heat Treatment Sensitivity: The properties can vary significantly with heat treatment, requiring careful control during processing.
Historically, 86L20 has been utilized in various sectors, including automotive and machinery, due to its balance of properties and cost-effectiveness.
Alternative Names, Standards, and Equivalents
Standard Organization | Designation/Grade | Country/Region of Origin | Notes/Remarks |
---|---|---|---|
UNS | G86200 | USA | Closest equivalent to AISI 8620 |
AISI/SAE | 8620 | USA | Minor compositional differences to be aware of |
ASTM | A29/A29M | USA | General specification for alloy steels |
EN | 1.6523 | Europe | Equivalent grade in European standards |
DIN | 20MnCr5 | Germany | Similar properties, but with different alloying elements |
JIS | SCr420 | Japan | Comparable grade with slight variations |
GB | 20CrMn | China | Equivalent with minor differences in composition |
The table above highlights various standards and equivalents for 86L20 steel. Notably, while AISI 8620 is often considered an equivalent, it may exhibit slight variations in mechanical properties and chemical composition that could affect performance in specific applications.
Key Properties
Chemical Composition
Element (Symbol and Name) | Percentage Range (%) |
---|---|
C (Carbon) | 0.18 - 0.23 |
Mn (Manganese) | 0.60 - 0.90 |
Cr (Chromium) | 0.40 - 0.60 |
Mo (Molybdenum) | 0.15 - 0.25 |
Si (Silicon) | 0.15 - 0.40 |
P (Phosphorus) | ≤ 0.035 |
S (Sulfur) | ≤ 0.040 |
The primary alloying elements in 86L20 steel include carbon, manganese, and chromium. Carbon enhances hardness and strength, while manganese improves hardenability and toughness. Chromium contributes to wear resistance and overall strength, making it a critical element for applications requiring durability.
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 | 620 - 750 MPa | 90 - 110 ksi | ASTM E8 |
Yield Strength (0.2% offset) | Annealed | Room Temp | 350 - 450 MPa | 50 - 65 ksi | ASTM E8 |
Elongation | Annealed | Room Temp | 20 - 25% | 20 - 25% | ASTM E8 |
Hardness (Brinell) | Annealed | Room Temp | 200 - 250 HB | 200 - 250 HB | ASTM E10 |
Impact Strength | Charpy V-notch | -20 °C | 30 - 50 J | 22 - 37 ft-lbf | ASTM E23 |
The mechanical properties of 86L20 steel make it suitable for applications requiring high strength and toughness. Its tensile and yield strengths indicate that it can withstand significant loads, while its elongation percentage shows good ductility, allowing for deformation without fracture.
Physical Properties
Property | Condition/Temperature | Value (Metric) | Value (Imperial) |
---|---|---|---|
Density | Room Temp | 7.85 g/cm³ | 0.284 lb/in³ |
Melting Point/Range | - | 1425 - 1540 °C | 2600 - 2800 °F |
Thermal Conductivity | Room Temp | 45 W/m·K | 31.2 BTU·in/(hr·ft²·°F) |
Specific Heat Capacity | Room Temp | 460 J/kg·K | 0.11 BTU/lb·°F |
Electrical Resistivity | Room Temp | 0.00065 Ω·m | 0.00038 Ω·in |
The density of 86L20 steel indicates it is relatively heavy, which is typical for alloy steels. Its thermal conductivity is moderate, making it suitable for applications where heat dissipation is necessary. The specific heat capacity suggests it can absorb a reasonable amount of heat before experiencing significant temperature changes.
Corrosion Resistance
Corrosive Agent | Concentration (%) | Temperature (°C/°F) | Resistance Rating | Notes |
---|---|---|---|---|
Chlorides | 3-10 | 20-60 / 68-140 | Fair | Risk of pitting |
Sulfuric Acid | 10-20 | 20-40 / 68-104 | Poor | Not recommended |
Sodium Hydroxide | 5-10 | 20-60 / 68-140 | Fair | Susceptible to stress corrosion cracking |
86L20 steel exhibits moderate resistance to corrosion in various environments. It is particularly susceptible to pitting in chloride environments and shows poor performance in acidic conditions. Compared to stainless steels, such as 304 or 316, 86L20's corrosion resistance is significantly lower, making it less suitable for applications in highly corrosive environments.
In comparison to other alloy steels, such as AISI 4140, 86L20 may offer better machinability but at the cost of lower corrosion resistance. This trade-off should be considered when selecting materials for specific applications.
Heat Resistance
Property/Limit | Temperature (°C) | Temperature (°F) | Remarks |
---|---|---|---|
Max Continuous Service Temp | 400 °C | 752 °F | Suitable for moderate temperatures |
Max Intermittent Service Temp | 500 °C | 932 °F | Short-term exposure only |
Scaling Temperature | 600 °C | 1112 °F | Risk of oxidation beyond this temp |
At elevated temperatures, 86L20 steel maintains its mechanical properties up to a certain limit. However, beyond its maximum continuous service temperature, it may experience oxidation and loss of strength. This makes it suitable for applications that involve moderate thermal exposure but not for high-temperature environments.
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 may be required |
86L20 steel is generally considered to have good weldability. However, preheating is often recommended to prevent cracking, especially in thicker sections. Post-weld heat treatment can also enhance the properties of the weld joint.
Machinability
Machining Parameter | [86L20 Steel] | [AISI 1212] | Notes/Tips |
---|---|---|---|
Relative Machinability Index | 70 | 100 | Good for machining |
Typical Cutting Speed (Turning) | 30 m/min | 50 m/min | Adjust based on tooling |
86L20 steel offers good machinability, though it is not as easy to machine as some free-cutting steels like AISI 1212. Optimal cutting speeds and tooling should be employed to achieve the best results.
Formability
86L20 steel can be cold and hot formed, but care must be taken to avoid work hardening. The minimum bend radius should be considered during forming operations to prevent cracking.
Heat Treatment
Treatment Process | Temperature Range (°C/°F) | Typical Soaking Time | Cooling Method | Primary Purpose / Expected Result |
---|---|---|---|---|
Annealing | 600 - 700 / 1112 - 1292 | 1 - 2 hours | Air | Softening, improving ductility |
Quenching | 850 - 900 / 1562 - 1652 | 30 minutes | Oil or Water | Hardening |
Tempering | 400 - 600 / 752 - 1112 | 1 hour | Air | Reducing brittleness, improving toughness |
Heat treatment processes significantly affect the microstructure and properties of 86L20 steel. Annealing softens the material, while quenching increases hardness. Tempering is crucial to reduce brittleness and improve toughness, making it suitable for various applications.
Typical Applications and End Uses
Industry/Sector | Specific Application Example | Key Steel Properties Utilized in this Application | Reason for Selection |
---|---|---|---|
Automotive | Gears and Shafts | High strength, good machinability | Durability and performance |
Machinery | Crankshafts | Toughness, wear resistance | Reliability under load |
Oil & Gas | Valve Components | Corrosion resistance, strength | Performance in harsh environments |
Other applications include:
- Structural components in machinery
- Tooling and dies
- Fasteners and bolts
86L20 steel is chosen for these applications due to its balance of strength, toughness, and machinability, making it suitable for components that experience dynamic loads.
Important Considerations, Selection Criteria, and Further Insights
Feature/Property | [86L20 Steel] | [AISI 4140] | [AISI 8620] | Brief Pro/Con or Trade-off Note |
---|---|---|---|---|
Key Mechanical Property | Good strength | Higher strength | Moderate strength | 4140 offers higher strength but less machinability |
Key Corrosion Aspect | Fair | Fair | Good | 8620 has better corrosion resistance |
Weldability | Good | Moderate | Good | 4140 may require preheating |
Machinability | Good | Moderate | Good | 4140 is harder to machine |
Formability | Moderate | Poor | Good | 8620 is more formable |
Approx. Relative Cost | Moderate | Higher | Moderate | 4140 is generally more expensive |
Typical Availability | Common | Common | Common | All grades are widely available |
When selecting 86L20 steel, considerations include its mechanical properties, cost-effectiveness, and availability. While it offers good performance for many applications, alternatives like AISI 4140 or AISI 8620 may be more suitable depending on specific requirements, such as higher strength or better corrosion resistance.
In summary, 86L20 steel is a versatile medium-carbon alloy steel with a range of applications across various industries. Its balance of properties makes it a reliable choice for components that require strength, toughness, and machinability, while its limitations in corrosion resistance should be carefully considered in the selection process.