Spherical ASTM A228 Steel Powder (UNS K08500)

ASTM A228 Steel Spherical Powder (UNS K08500) Product Information -:- For detailed product information, please contact sales. -: ASTM A228 Steel Spherical Powder (UNS K08500) Synonyms -:- For detailed product information, please contact sales. -: -:- For detailed product information, please contact sales. -: Spherical ASTM A228 Steel Powder (UNS K08500) characteristics -:- For detailed product information, please contact sales. -: Spherical ASTM A228 Steel Powder (UNS K08500) Particle Size -:- For detailed product information, please contact sales. -: -:- -:- 0-15μm ,5-25μm, 15-45μm, 15-53μm,20-63um, 45-75μm, 45-105μm, 45-150μm ,75-150μm. (Various granularities can be customized according to customer requirements) -:- For detailed product information, please contact sales. -:

Spherical ASTM A228 Steel Powder (UNS K08500) Applicable processes -:- For detailed product information, please contact sales. -: Laser/electron beam additive manufacturing (SLM/EBM, 3D printing) Direct laser deposition (DLD) Used in thermal spray (TSA) Powder hot isostatic pressing (HIP) Metal injection molding (MIM) Powder metallurgy (PM) Laser cladding (LC), etc. -:- For detailed product information, please contact sales. -: Spherical ASTM A228 Steel Powder (UNS K08500) Chemical Composition -:- For detailed product information, please contact sales. -: -:- For detailed product information, please contact sales. -: ASTM A228 Steel (UNS K08500) Product Information -:- For detailed product information, please contact sales. -: # **Technical Datasheet: ASTM A228 / UNS K08500 High-Carbon Steel Wire (Music Wire / Piano Wire)** ## **1. Product Overview** **ASTM A228** (also designated **UNS K08500**) is a premium high-carbon, cold-drawn spring steel wire universally recognized as **"Music Wire"** or **"Piano Wire."** It represents the highest strength and most precise general-purpose spring wire available in the carbon steel family. This wire is characterized by its exceptionally high tensile strength, excellent fatigue life, fine surface finish, and consistent dimensional tolerances, achieved through specialized processing including patenting and severe cold drawing. It is supplied in the **"hard-drawn"** or **"spring tempered"** condition, meaning it is ready for spring coiling without further heat treatment (except for a low-temperature stress relief). The wire derives its properties from a combination of its chemistry and the intense cold work imparted during drawing. --- ## **2. Key International Standards & Designations** | Standard Type | Designation | Title / Description | | :--- | :--- | :--- | | **Primary Standard (USA)** | **ASTM A228/A228M** | Standard Specification for Steel, Spring Wire, Music Quality (Cold-Drawn), General Purpose | | **Unified Numbering System** | **UNS K08500** | Designation for the specific steel composition | | **SAE Specification** | **SAE J217** | Music Wire (Spring Quality) - Provides supplementary requirements | | **ISO Equivalent** | **ISO 8458-2** | Mechanical springs — Steel wire — Part 2: Oil-tempered or cold-drawn non-alloy steel wire (Type FD for cold-drawn, highest class) | | **European (EN) Equivalent** | **EN 10270-1:2011** | Steel wire for mechanical springs — Part 1: Patented cold-drawn unalloyed spring steel wire (Class SH - highest tensile) | | **Japanese (JIS) Equivalent** | **JIS G 3522** | Hard Drawn Steel Spring Wire (Similar grade) | --- ## **3. Chemical Composition** The composition is optimized for maximum strength through cold work while maintaining sufficient ductility for coiling. | Element | Composition Range (%) | Typical (%) | Metallurgical Role | | :--- | :--- | :--- | :--- | | **Carbon (C)** | 0.70 - 0.85 | 0.80 | Primary strengthening element; enables high strength after cold drawing. | | **Manganese (Mn)** | 0.20 - 0.60 | 0.45 | Enhances hardenability during patenting and contributes to strength. | | **Phosphorus (P)** | 0.025 max | 0.015 | Impurity; kept very low to prevent embrittlement. | | **Sulfur (S)** | 0.025 max | 0.015 | Impurity; controlled to ensure good fatigue performance. | | **Silicon (Si)** | 0.10 - 0.30 | 0.22 | Provides solid solution strengthening; improves elasticity. | | **Copper (Cu)** | **0.20 min** (often) | 0.25+ | **Distinguishing Feature:** Intentional addition to improve atmospheric corrosion resistance. | **Key Notes on Chemistry:** * The **minimum copper (Cu) content** is a defining requirement that differentiates A228 from other high-carbon spring wires (like A227). This provides a marginal but valuable improvement in rust resistance. * Steel is produced to a **"music quality"** cleanliness, meaning strict controls on non-metallic inclusions to ensure superior fatigue performance. --- ## **4. Physical & Mechanical Properties** ### **4.1 Typical As-Delivered Properties (Cold-Drawn Condition)** *Wire is supplied in a heavily cold-worked state, providing its final mechanical properties.* | Property | Description & Typical Values | | :--- | :--- | | **Tensile Strength** | **Extremely High.** Varies inversely with wire diameter.
**Typical Range:** 2250 - 3100 MPa (325 - 450 ksi).
**Example:** ~2800 MPa for 1.0 mm wire; ~2400 MPa for 3.0 mm wire. | | **Modulus of Elasticity (E)** | ~200 - 207 GPa (29 - 30 x 10⁶ psi) | | **Torsional Ducitlity** | Excellent for its strength. Must pass a specified minimum number of twists in a standardized test (per ASTM A228), proving its ability to be coiled without fracturing. | | **Surface Finish** | **Exceptionally smooth and bright.** Must be free of seams, scale, rust, and other defects detrimental to fatigue life. | | **Dimensional Tolerance** | Very tight tolerances (e.g., ±0.001" or ±0.025mm for common sizes), critical for precision spring manufacturing. | | **Decarburization** | Strictly controlled. Must be essentially free of total decarburization (ferrite ring) on the surface. | ### **4.2 Microstructure** Consists of a very fine, heavily deformed **pearlitic** or **cold-drawn patented** structure, which is responsible for its ultra-high strength. --- ## **5. Typical Product Applications** ASTM A228 is the material of choice for small, high-stress, dynamic springs where space is limited and performance is critical. * **Precision Mechanical Springs:** * **Compression & Extension Springs:** For valves, actuators, switches, and instruments. * **Torsion Springs:** In clutches, hinges, and electromechanical devices. * **Consumer & Industrial Products:** * Brush springs, snap-action springs, spring clips, retaining rings. * Springs in writing instruments, toys, appliances, and tools. * **Original Namesake Applications:** * **Piano Strings / Music Wire:** High-grade strings for musical instruments. * **Springs for Musical Instruments:** Reeds, triggers, etc. * **Specialized Uses:** * Valve springs for small engines. * Springs in medical devices and precision measuring equipment. * Used where the highest strength-to-size ratio is needed among non-alloy steels. --- ## **6. Manufacturing & Processing** * **Raw Material:** High-carbon steel rod. * **Key Process:** **Patenting** – a specialized isothermal heat treatment that produces a fine, uniform pearlitic structure ideal for severe cold drawing. * **Final Processing:** Repeated **cold drawing** through progressively smaller dies with intermediate anneals if necessary. This severe plastic deformation is what creates the ultra-high strength. * **Finishing:** May be supplied **bright** (uncoated) or with a very thin protective coating (e.g., tin, zinc, or phosphate) for storage. * **Spring Making:** Wire is **cold coiled** on spring coiling machines. A low-temperature **stress relief bake** (~230-260°C / 450-500°F for 30-60 minutes) is typically applied after coiling to stabilize spring geometry and relieve residual stresses. --- ## **7. Comparison & Selection Guide** * **vs. ASTM A227 (Hard-Drawn MB Grade):** A228 has higher and more consistent tensile strength, better surface finish, tighter tolerances, and includes copper for corrosion resistance. A227 is a more economical, general-purpose hard-drawn wire. * **vs. ASTM A229 (Oil-Tempered Wire):** A229 is heat-treated (quenched & tempered), not cold-drawn. A228 typically has higher tensile strength for a given diameter but may have slightly lower torsional ductility. A229 is often preferred for larger diameters and less complex shapes. * **vs. Alloy Spring Wires (e.g., ASTM A401):** Alloy wires (Cr-Si, Cr-V) offer better high-temperature performance and relaxation resistance. A228 is stronger at room temperature but loses strength more rapidly as temperature increases (>120°C / 250°F). --- ## **8. Important Design & Handling Notes** * **Temperature Limit:** Not recommended for continuous service above **120°C (250°F)**. Strength decreases and stress relaxation increases at elevated temperatures. * **Corrosion Resistance:** The copper addition provides only mild atmospheric corrosion resistance. For corrosive environments, stainless steel or coated springs are recommended. * **Formability:** Despite its high strength, it possesses excellent torsional ductility for coiling. However, bending or secondary forming after drawing is limited. * **Fatigue Life:** Excellent in clean, properly designed applications. Surface integrity is paramount—any nicks or scratches act as stress concentrators and drastically reduce fatigue life. ## **9. Conclusion** **ASTM A228 / UNS K08500 Music Wire** remains the benchmark for high-strength, precision carbon steel spring wire. Its unparalleled combination of ultra-high tensile strength, excellent fatigue resistance, fine surface finish, and dimensional precision makes it an indispensable material for engineers designing compact, high-performance springs for dynamic applications. When the design calls for the maximum force from the smallest possible spring in a benign to moderate environment, A228 is very often the premier and most reliable choice. -:- For detailed product information, please contact sales. -: ASTM A228 Steel (UNS K08500) Specification Dimensions Size： Diameter 20-1000 mm Length <5207 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: ASTM A228 Steel (UNS K08500) Properties -:- For detailed product information, please contact sales. -:

Spherical ASTM A228 Steel Powder (UNS K08500) Particle Size Description -:- For detailed product information, please contact sales. -: Applications of Spherical ASTM A228 Steel Powder (UNS K08500) -:- For detailed product information, please contact sales. -: -:- For detailed product information, please contact sales. -: Applications of ASTM A228 Steel Spherical Powder (UNS K08500) -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A228 Steel Spherical Powder (UNS K08500) -:- For detailed product information, please contact sales. -:

Packing of ASTM A228 Steel Spherical Powder (UNS K08500) -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and Steel Spherical Powder drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 1678 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition