AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA)

AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) Product Information -:- For detailed product information, please contact sales. -: AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) Synonyms -:- For detailed product information, please contact sales. -:

AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) Product Information -:- For detailed product information, please contact sales. -: **Product Name:** AK Steel ASTM A1011, Class 1 Formable, Grade 50K Hot-Rolled Medium/High Strength Low-Alloy Steel (HSLA) --- ### **1. Overview** AK Steel's ASTM A1011 **Grade 50K, Class 1 Formable** is a premium microalloyed High-Strength Low-Alloy (HSLA) steel that achieves an exceptional balance between high strength and superior cold formability. With a minimum yield strength of 50 ksi (345 MPa), it belongs to the high-strength tier of hot-rolled products. The **"K" suffix** confirms microalloying with Columbium (Niobium) and/or Vanadium for grain refinement, while the **"Class 1 Formable"** designation indicates this steel meets the most stringent ductility and forming requirements within the A1011 specification. It is engineered for applications where significant weight reduction through down-gauging must be paired with the ability to create complex geometries through demanding forming operations. --- ### **2. International Standards** This product conforms to the following North American standard, specifically meeting its enhanced formability criteria: * **ASTM A1011 / A1011M:** Standard Specification for Steel, Sheet and Strip, Hot-Rolled, Carbon, Structural, High-Strength Low-Alloy and High-Strength Low-Alloy with Improved Formability. * **Grade:** 50K (Microalloyed HSLA Steel) * **Formability Class:** **Class 1 (Formable).** This classification imposes stricter limits on tensile strength and guarantees higher minimum elongation compared to the standard Class 2 (Structural), prioritizing manufacturability in complex parts. --- ### **3. Chemical Composition (Typical, % by Weight)** The chemistry is a sophisticated, low-carbon microalloyed design that prioritizes formability and weldability alongside strength. | Element | Content (Typical / Maximum) | Role & Implication | | :--- | :--- | :--- | | **Carbon (C)** | 0.08% - 0.14% max | Very low level for a 50 ksi steel, essential for excellent cold formability and weldability. Strength is derived predominantly from microalloying. | | **Manganese (Mn)** | 1.15% - 1.50% | Primary solid solution strengthener; supports hardenability and works synergistically with microalloys. | | **Phosphorus (P)** | 0.035% max | Residual; kept low. | | **Sulfur (S)** | 0.035% max | Residual; controlled for improved transverse properties. | | **Silicon (Si)** | 0.10% - 0.40% | Deoxidizer and solid solution strengthener. | | **Columbium (Cb/Nb)** | **0.02% - 0.06%** | **Critical Microalloy.** Primary agent for grain refinement and precipitation strengthening, enabling high strength with low carbon. | | **Vanadium (V)** | **0.03% - 0.08%** (Often used with Nb) | **Key Microalloy.** Provides potent precipitation strengthening via vanadium carbonitrides. | | **Aluminum (Al), Total** | 0.010% min | Grain refiner for fine austenite grain size. | | **Nitrogen (N)** | Controlled | Optimized to interact with microalloys for effective precipitation. | | **Key Characteristic:** | **Exceptionally Low Carbon Equivalent (CE).** Typically ≤ 0.38. This is the foundation of its superior formability and weldability for a 50 ksi yield strength steel. | | --- ### **4. Physical & Mechanical Properties** Properties are tailored for fabrication, with the Class 1 designation ensuring enhanced ductility. | Property | Specification Minimum (ASTM A1011, Grade 50K, Class 1) | Typical Value / Description | | :--- | :--- | :--- | | **Yield Strength (min)** | 50 ksi (345 MPa) | | | **Tensile Strength** | **65 ksi min, with a typical *maximum* limit enforced** | **Key Class 1 Feature.** A controlled upper limit on tensile strength (e.g., 75-80 ksi max) ensures a favorable, lower yield-to-tensile ratio (Y/T) for better formability. Typically 65-75 ksi. | | **Yield-to-Tensile Ratio (Y/T)** | **Lower than Class 2** | Typically 0.77 - 0.83. A lower ratio indicates better strain distribution during forming, reducing the risk of localized thinning or fracture. | | **Elongation in 2" (min)** | **Higher than Class 2** (e.g., 20-22% min, depending on thickness) | **Key Class 1 Feature.** Guarantees superior ductility for stretching and drawing operations, essential for complex parts. | | **Modulus of Elasticity** | 29,000 ksi (200 GPa) | | | **Notch Toughness** | **Excellent.** The fine-grained, acicular ferrite microstructure from microalloying provides outstanding impact resistance, even at lower temperatures. | | | **Fatigue Strength** | High | Good resistance to cyclic loading due to clean microstructure. | | **Surface Finish** | Standard hot-rolled mill finish. | | --- ### **5. Key Features & Advantages** * **Unmatched Strength-Formability Combination:** Delivers 50 ksi minimum yield strength while being explicitly qualified for severe forming operations, a rare and valuable combination. * **Outstanding Weldability:** The very low carbon equivalent allows for welding with minimal or no preheat in most thicknesses, dramatically simplifying fabrication and reducing costs. * **Superior Toughness:** The microalloyed, fine-grained structure provides best-in-class resistance to brittle fracture and excellent impact performance. * **Maximum Weight Savings:** The high strength allows for the most aggressive down-gauging, significantly reducing part weight, material usage, and lifecycle energy consumption. * **Consistent & Predictable Performance:** Advanced processing ensures uniform properties coil-to-coil and excellent dimensional consistency. --- ### **6. Product Applications** ASTM A1011 Grade 50K Class 1 is specified for the most challenging applications where high strength and complex forming are both required. * **Automotive Safety & Chassis Components:** Critical safety parts like door intrusion beams, bumper reinforcements, and complex subframe components requiring high strength-energy absorption and formed shapes. * **Heavy Truck & Trailer Components:** Formed main rails, crossmembers, and suspension components where weight reduction directly translates to increased payload. * **Construction & Agricultural Equipment:** Formed booms, arms, and cabs for excavators, loaders, and combines that require both lightweight design and durability. * **Material Handling Equipment:** Complexly formed parts for forklift masts, loader arms, and automated guided vehicle (AGV) frames. * **Off-Highway Vehicle Frames:** Structural members for recreational and utility vehicles that undergo significant forming during manufacture. * **Energy Sector Components:** Formed brackets, supports, and housings in wind turbines and other equipment where strength-to-weight is critical. --- ### **7. Fabrication & Processing Notes** * **Forming:** Excellent for demanding cold forming, including deep drawing, stretch forming, and roll-forming. The lower Y/T ratio and high elongation allow for more uniform metal flow. Minimum bend radii are typically 2.5x to 3x material thickness. Use of forming lubricants is recommended for complex shapes. * **Welding:** **Exceptionally weldable.** Use low-hydrogen processes (GMAW with 90/10 Ar/CO₂, FCAW-G). Preheating (50-150°F / 10-65°C) is generally only recommended for very thick sections (>1") or highly restrained joints. Matching-strength filler metals (70-80 ksi tensile) are typical. * **Cutting:** All thermal cutting methods (plasma, laser) are ideal. Shearing requires higher tonnage. * **Surface Preparation:** Mill scale must be removed via abrasive blasting or pickling for painting or coating. * **Springback:** Significant springback should be anticipated and compensated for in tooling design due to the high yield strength. --- **Disclaimer:** *This profile is a technical summary. AK Steel is now part of Cleveland-Cliffs Inc.* For engineering and procurement, always consult the latest official **ASTM A1011** specification and the certified **Mill Test Report (MTR)**. It is **critical** to specify both the **grade (50K)** and the **formability class (Class 1)** in procurement documents (e.g., "ASTM A1011, Grade 50K, Class 1 Formable") to ensure receipt of the material with enhanced ductility properties. The MTR will verify compliance with these specific requirements. -:- For detailed product information, please contact sales. -: AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) Specification Dimensions Size： Diameter 20-1000 mm Length <4595 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. -: AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) Properties -:- For detailed product information, please contact sales. -:

Applications of AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) -:- For detailed product information, please contact sales. -: Chemical Identifiers AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) -:- For detailed product information, please contact sales. -:

Packing of AK Steel ASTM A 1011, Class 1 Formable, Grade 50K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) -:- 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 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 1066 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