SAE 1087 is a high-carbon steel grade that occupies a unique position in the spectrum of carbon steels used across manufacturing industries. While not as widely discussed as its more common counterparts like 1045 or 1060, SAE 1087 offers a distinctive combination of strength, hardness, and wear resistance that makes it invaluable for specific engineering applications. This comprehensive guide explores the chemical composition, mechanical properties, machining characteristics, and practical applications of SAE 1087, providing engineers and procurement specialists with the technical depth needed to make informed material selection decisions. Understanding the nuances of this high-carbon steel is essential for anyone involved in precision CNC machining, fastener production, or spring manufacturing.
Chemical Composition of SAE 1087
The chemical composition of SAE 1087 defines its fundamental characteristics and determines how the material responds to heat treatment, machining, and forming processes. This high-carbon steel grade is part of the AISI/SAE 10xx series, which comprises plain carbon steels with manganese as the primary alloying addition.
Standard Composition Ranges
The nominal composition of SAE 1087 steel follows the specifications outlined by the Society of Automotive Engineers (SAE) and the American Iron and Steel Institute (AISI). The carbon content, which ranges from 0.85% to 0.90%, places this grade firmly in the high-carbon category, giving it exceptional hardness potential after heat treatment. The manganese content, typically between 0.60% and 0.90%, contributes to hardenability and helps control the effects of sulfur and phosphorus impurities during processing.
Typical composition values for SAE 1087 steel are presented in the table below. These values represent standard ranges; actual compositions may vary slightly depending on the specific manufacturer and the intended end-use application.
| Élément | Plage de composition (%) | Typical Value (%) |
|---|---|---|
| Carbone (C) | 0.85 – 0.90 | 0.87 |
| Manganèse (Mn) | 0.60 – 0.90 | 0.75 |
| Phosphore (P) | 0,040 max | 0.020 |
| Soufre (S) | 0.050 max | 0.025 |
| Fer (Fe) | Équilibre | ~98.3 |
Typical values based on standard SAE J403 specifications.
Rôle des éléments d’alliage
Carbon is the dominant alloying element in SAE 1087, and its relatively high concentration is responsible for the steel’s ability to achieve high hardness and strength through heat treatment. When carbon content exceeds 0.80%, the steel becomes increasingly capable of forming hard cementite (iron carbide) phases, which significantly enhance wear resistance at the expense of ductility and weldability.
Manganese serves multiple functions in this steel grade. It acts as a deoxidizer during steelmaking, improves hardenability by shifting the time-temperature-transformation (TTT) curves, and combines with sulfur to form manganese sulfide inclusions that improve machinability. The manganese content in SAE 1087 is carefully balanced to provide these benefits without promoting excessive grain growth during heat treatment.
Phosphorus and sulfur are considered impurity elements in SAE 1087. While they are kept to low maximums, sulfur can actually be beneficial in small amounts for chip breaking during machining operations. The relatively tight control of these elements ensures consistent mechanical properties across different heats and production batches.
Mechanical Properties of SAE 1087
The mechanical properties of SAE 1087 steel vary significantly depending on the heat treatment condition. In the as-rolled or normalized state, the material exhibits moderate strength and ductility. However, after proper quenching and tempering, SAE 1087 can achieve tensile strengths exceeding 1000 MPa, making it suitable for demanding structural and mechanical applications.
Properties in Different Heat Treatment Conditions
The table below summarizes the typical mechanical properties of SAE 1087 in various conditions. These values are representative and should be verified with specific material test certificates for critical applications.
| État | Résistance à la traction (MPa) | Limite d’élasticité (MPa) | Allongement (%) | Dureté (HB) |
|---|---|---|---|---|
| Hot Rolled | 690 – 760 | 415 – 480 | 12 – 15 | 200 – 220 |
| Normalisé | 760 – 830 | 450 – 520 | 10 – 12 | 220 – 240 |
| Quenched & Tempered (600°C) | 850 – 950 | 550 – 650 | 15 – 18 | 250 – 280 |
| Quenched & Tempered (400°C) | 1100 – 1250 | 900 – 1050 | 8 – 10 | 320 – 360 |
| Oil Quenched (as quenched) | 1800 – 2000 | 1400 – 1600 | 1 – 2 | 550 – 600 |
Typical values; actual properties depend on section size, quenching medium, and tempering parameters.
Fatigue and Impact Resistance
SAE 1087 exhibits good fatigue resistance when properly heat treated, particularly in the quenched and tempered condition. The high carbon content promotes the formation of a fine, tempered martensite microstructure that can withstand repeated cyclic loading without crack initiation. This makes the material suitable for applications such as coil springs, clutch plates, and other components subjected to dynamic stresses.
Impact resistance, however, is a limitation of SAE 1087 in high-hardness conditions. The steel tends to exhibit lower Charpy V-notch impact values compared to lower-carbon grades like 1045 or alloy steels such as 4140. Engineers must carefully consider the operating temperature and potential for impact loading when specifying SAE 1087. In sub-zero environments, the ductile-to-brittle transition temperature can become a critical design factor.
Physical Properties and Thermal Characteristics
Beyond mechanical performance, the physical properties of SAE 1087 influence how the material behaves during machining, heat treatment, and in-service thermal cycling. These properties are essential for process engineers designing manufacturing workflows and product engineers evaluating application suitability.
Density, Thermal, and Electrical Properties
The physical properties of SAE 1087 are typical of high-carbon steels, with a density that remains essentially constant regardless of heat treatment condition. The thermal conductivity is moderate and decreases slightly with increasing temperature, which affects heat dissipation during machining and in-service performance.
| Propriété | Valeur | Unité |
|---|---|---|
| Densité | 7.85 | g/cm³ |
| Point de fusion | 1425 – 1460 | °C |
| Thermal Conductivity (at 20°C) | 45 – 50 | W/(m·K) |
| Thermal Conductivity (at 500°C) | 35 – 40 | W/(m·K) |
| Specific Heat Capacity (at 20°C) | 470 – 490 | J/(kg·K) |
| Electrical Resistivity (at 20°C) | 0.16 – 0.18 | µΩ·m |
| Mean Coefficient of Thermal Expansion (20-200°C) | 11.5 – 12.5 | ×10⁻⁶ /K |
| Mean Coefficient of Thermal Expansion (20-600°C) | 14.0 – 15.0 | ×10⁻⁶ /K |
Typical values for carbon steel with 0.85-0.90% carbon content.
Propriétés magnétiques
SAE 1087 is ferromagnetic at room temperature, exhibiting relative permeability values in the range of 100 to 500 depending on the microstructure and heat treatment condition. Quenched martensitic structures have lower permeability compared to annealed ferritic-pearlitic structures. This property may be relevant for applications where magnetic behavior is a design consideration, such as in electromagnetic actuators or sensor components.
The Curie temperature of SAE 1087 is approximately 770°C, above which the material loses its ferromagnetic properties and becomes paramagnetic. This is consistent with most plain carbon steels and is rarely a limiting factor in typical engineering applications.
Heat Treatment and Hardenability
Heat treatment is the critical process that unlocks the full potential of SAE 1087 steel. The high carbon content allows for significant hardening, but it also demands careful process control to prevent cracking, excessive distortion, or the formation of undesirable microstructures.
Recuit et normalisation
For optimal machinability, SAE 1087 is typically supplied in the annealed or spheroidized condition. Full annealing involves heating to approximately 760-790°C, holding for sufficient time to ensure complete austenitization, followed by very slow cooling in the furnace. This produces a soft, ferritic-pearlitic microstructure with hardness values around 180-200 HB, which is much easier to machine than the normalized or hardened condition.
Spheroidize annealing is particularly beneficial for this high-carbon steel grade. The process involves heating to just below the lower critical temperature (around 700°C) and holding for extended periods, followed by slow cooling. This transforms the lamellar pearlite into spheroidal cementite particles within a ferrite matrix, reducing hardness to approximately 160-180 HB and dramatically improving machinability and cold formability.
Normalizing, which involves air cooling from the austenitizing temperature, produces a finer pearlitic structure with higher strength but reduced machinability compared to annealed material. Normalizing is often used as a preparatory step before final hardening to refine the grain structure.
Trempe et revenu
Hardening of SAE 1087 requires austenitizing at temperatures between 790°C and 830°C, followed by rapid quenching in oil or a polymer quenchant. Water quenching is generally avoided for this steel grade due to the high risk of cracking caused by the severe thermal stresses and the high carbon content. The critical cooling rate to achieve full martensitic transformation is relatively low due to the high carbon and manganese content, making oil quenching effective for most section sizes.
After quenching, the material is in a hard, brittle condition with hardness values typically exceeding 55 HRC. Tempering is mandatory to relieve internal stresses and restore some ductility while maintaining acceptable strength levels. Tempering temperatures range from 150°C to 650°C, with higher temperatures producing lower hardness but improved toughness. The table below provides guidance on achievable hardness values at various tempering temperatures.
| Tempering Temperature (°C) | Dureté (HRC) | Résistance à la traction (MPa) | Application typique |
|---|---|---|---|
| 150 – 200 | 55 – 58 | 1900 – 2100 | Cutting tools, wear parts |
| 300 – 350 | 48 – 52 | 1600 – 1800 | Springs, high-strength components |
| 450 – 500 | 40 – 45 | 1300 – 1500 | Structural parts, gears |
| 550 – 600 | 32 – 38 | 1000 – 1200 | Toughness-critical components |
Typical values for oil-quenched SAE 1087, 25mm round bar.
Considérations relatives à l’usinage et à la fabrication
Machining SAE 1087 presents unique challenges compared to lower-carbon steels. The high carbon content contributes to work hardening, abrasive wear on cutting tools, and the formation of difficult-to-control chips. However, with proper tooling selection and process parameters, excellent results can be achieved in CNC machining operations.
Choix des outils et paramètres d’usinage
For turning and milling operations on SAE 1087, carbide inserts with appropriate coatings are the standard choice. CVD-coated carbide grades with aluminum oxide (Al₂O₃) layers provide excellent resistance to the abrasive wear and high cutting temperatures encountered when machining this steel. For interrupted cuts or rigid setups, ceramic inserts can be used at higher cutting speeds, though they require greater machine stability.
Recommended cutting parameters for SAE 1087 in the annealed condition include cutting speeds of 60-90 m/min for carbide tools, feed rates of 0.15-0.30 mm/rev for roughing, and 0.05-0.15 mm/rev for finishing. Depth of cut should be limited to 2-4 mm for roughing operations to manage cutting forces and heat generation. When machining hardened material (above 45 HRC), CBN (cubic boron nitride) inserts are recommended, with reduced cutting speeds of 80-120 m/min and lighter depths of cut.
Chip Control and Surface Finish
The high carbon content of SAE 1087 produces stringy, continuous chips that can become entangled in the tooling and workpiece. Effective chip breaking is essential, achieved through the use of chip breaker geometries on the insert and appropriate feed rates. High-pressure coolant delivery at 50-100 bar can significantly improve chip evacuation and tool life by reducing the cutting temperature at the tool-chip interface.
Achieving good surface finish on SAE 1087 requires attention to cutting speed, feed rate, and tool nose radius. A larger nose radius (0.8-1.2 mm) generally produces better surface finish but increases cutting forces. For finishing operations, a final pass with a depth of cut of 0.25-0.50 mm and a feed rate of 0.05-0.10 mm/rev typically yields surface roughness values of Ra 0.8-1.6 µm. When machining this steel for precision components like Poissons de changement de vitesse usinés par CNC, tighter tolerances may require additional grinding or polishing operations.
Comparison with Related Steel Grades
Understanding how SAE 1087 compares to other carbon steel grades helps engineers select the optimal material for their specific application. The table below provides a comparison with several related grades commonly used in manufacturing.
SAE 1087 vs. 1060, 1070, and 1095
| Propriété | SAE 1060 | SAE 1070 | SAE 1087 | SAE 1095 |
|---|---|---|---|---|
| Carbon Content (%) | 0.55 – 0.65 | 0.65 – 0.75 | 0.85 – 0.90 | 0.90 – 1.03 |
| Tensile Strength (Q&T, MPa) | 800 – 1000 | 900 – 1100 | 1100 – 1250 | 1200 – 1400 |
| Hardness (Q&T, HRC) | 25 – 35 | 30 – 40 | 40 – 48 | 45 – 55 |
| Machinability (relative) | Bonne | Passable | Passable | Mauvaise |
| Soudabilité | Passable | Mauvaise | Mauvaise | Very Poor |
| Typical Cost (relative) | Faible | Low-Medium | Moyen | Medium-High |
Typical values for comparison purposes.
Selecting Between Grades
The choice between SAE 1087 and adjacent grades depends on the balance of strength, wear resistance, and manufacturability required. SAE 1060 offers better machinability and weldability but lower maximum hardness, making it suitable for general engineering components where moderate strength is sufficient. SAE 1095 provides higher maximum hardness and wear resistance but is significantly more difficult to machine and more prone to cracking during heat treatment.
SAE 1087 occupies a sweet spot for applications requiring high strength and wear resistance without the extreme brittleness and processing difficulty of 1095. It is often preferred for spring applications where the combination of high yield strength and acceptable fatigue life is critical. For components that require both the properties of SAE 1087 and complex geometries, precision CNC machining services can effectively produce parts from this material, as demonstrated in the manufacturing of various types of iron metals and steel components.
Typical Applications of SAE 1087
SAE 1087 finds its primary applications in components that demand high strength, good wear resistance, and the ability to withstand cyclic loading. The material’s properties make it particularly well-suited for the automotive, agricultural, and general engineering sectors.
Springs and Suspension Components
The most common application of SAE 1087 is in the production of coil springs, leaf springs, and torsion bars for automotive suspension systems. The high yield strength-to-weight ratio achievable through proper heat treatment allows for compact spring designs that can support substantial loads. The material’s fatigue resistance, when correctly processed, ensures reliable performance over millions of loading cycles. Spring manufacturers typically use SAE 1087 in the form of wire or bar stock, which is formed to shape before heat treatment.
For precision spring components that require tight dimensional tolerances, Comprendre les blocs de montage and associated hardware is essential, as these parts often interface with spring assemblies in mechanical systems.
Wear-Resistant and High-Strength Parts
Beyond springs, SAE 1087 is used for a variety of components requiring high surface hardness and wear resistance. These include clutch plates, cutting blades for agricultural implements, scraper blades, chisels, and various hand tools. In these applications, the steel is typically hardened to 50-55 HRC to provide a durable, wear-resistant surface while maintaining sufficient core toughness to resist fracture.
The material is also used in the manufacture of piano wire and music wire, where its high carbon content enables the production of thin, high-strength wire with excellent elastic properties. Additionally, SAE 1087 finds use in the production of needle rollers for bearings, where its hardness and fatigue resistance are advantageous.
Tuofa CNC: Precision Machining of SAE 1087
Tuofa CNC is a leading provider of precision CNC machining services, specializing in the fabrication of components from a wide range of materials, including high-carbon steels like SAE 1087. With advanced multi-axis CNC machining centers and a team of experienced engineers, Tuofa CNC delivers high-precision parts that meet the most demanding specifications.
Machining Capabilities for High-Carbon Steel
At Tuofa CNC Germany, our machining capabilities are specifically optimized for challenging materials like SAE 1087. We utilize rigid machine tools with high spindle torque to handle the cutting forces associated with high-carbon steel machining. Our tooling inventory includes a comprehensive selection of carbide and CBN inserts specifically designed for steel machining, ensuring optimal tool life and surface finish.
Our process engineers develop custom machining strategies for each SAE 1087 component, considering factors such as heat treatment condition, part geometry, and tolerance requirements. We employ high-pressure coolant systems to manage heat generation and chip evacuation, critical factors when machining this material. Whether producing small batches of prototype components or large production runs, Tuofa CNC ensures consistent quality and dimensional accuracy.
Assurance qualité et certification des matériaux
Tuofa CNC maintains a rigorous quality management system that includes material verification, in-process inspection, and final dimensional validation. For SAE 1087 components, we can provide material test certificates documenting the chemical composition and mechanical properties of the specific heat used for your parts. Our inspection capabilities include CMM (coordinate measuring machine) measurement, surface roughness testing, and hardness verification.
We understand that many of our clients in the automotive and industrial sectors require components that meet specific standards and regulations. Our team works closely with customers to ensure that all requirements are documented and met, from raw material sourcing through final packaging and delivery. For engineers seeking a reliable manufacturing partner for their SAE 1087 components, Tuofa CNC offers the technical expertise and production capability to bring designs to life with precision and efficiency.
Conclusion
SAE 1087 is a versatile high-carbon steel that offers an excellent balance of strength, hardness, and wear resistance for demanding engineering applications. Its chemical composition, with carbon content between 0.85% and 0.90%, enables substantial hardening through heat treatment while maintaining acceptable toughness when properly tempered. The material excels in spring manufacturing, wear-resistant components, and high-strength fasteners, though it requires careful attention to machining parameters and heat treatment practices. Compared to adjacent grades like 1060 and 1095, SAE 1087 provides a practical middle ground for applications requiring high performance without the extreme processing challenges of higher-carbon steels. By partnering with experienced CNC machining providers and following established best practices, engineers can successfully leverage SAE 1087 to produce reliable, high-performance components.