AK Steel ASTM A 1011, Class 1 Formable, Grade 45K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA)

AK Steel ASTM A 1011, Class 1 Formable, Grade 45K 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 45K 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 45K 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 45K Hot-Rolled Medium/High Strength Low-Alloy Steel (HSLA) --- ### **1. Overview** AK Steel's ASTM A1011 **Grade 45K, Class 1 Formable** represents a specialized class of microalloyed High-Strength Low-Alloy (HSLA) steel engineered to deliver a robust 45 ksi minimum yield strength while simultaneously achieving superior formability characteristics. The "K" suffix denotes **microalloying with Columbium (Niobium) and/or Vanadium**, while the **"Class 1 Formable"** designation indicates this steel meets the most stringent requirements for enhanced ductility and forming within the A1011 specification. It is designed for applications where a high strength-to-weight ratio must be combined with the ability to undergo moderate to severe cold forming, making it ideal for complex structural components in weight-sensitive designs. --- ### **2. International Standards** This product is manufactured to meet the specific requirements of the following standard, which includes provisions for enhanced formability: * **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:** 45K (Microalloyed HSLA) * **Formability Class:** **Class 1 (Formable).** This class imposes stricter limits on tensile strength and ensures higher minimum elongation values compared to standard Class 2 (Structural) grades, prioritizing fabricability. --- ### **3. Chemical Composition (Typical, % by Weight)** The chemistry is a precise balance of microalloying elements designed to achieve strength through grain refinement and precipitation hardening, while maintaining a low carbon equivalent for formability and weldability. | Element | Content (Typical / Maximum) | Role & Implication | | :--- | :--- | :--- | | **Carbon (C)** | 0.10% - 0.15% max | Kept low to ensure excellent formability and weldability. Primary strength comes from microalloys. | | **Manganese (Mn)** | 1.00% - 1.40% | Solid solution strengthener; essential for hardenability and supporting microalloy effects. | | **Phosphorus (P)** | 0.035% max | Residual; kept low. | | **Sulfur (S)** | 0.035% max | Residual; controlled for improved transverse ductility. | | **Silicon (Si)** | 0.10% - 0.40% | Deoxidizer and solid solution strengthener. | | **Columbium (Cb/Nb)** | **0.005% - 0.05%** | **Key Microalloy.** Primary agent for grain refinement during hot rolling, contributing to strength and toughness. | | **Vanadium (V)** | **0.01% - 0.08%** (May be used) | **Microalloy.** Provides additional precipitation strengthening and grain refinement. | | **Aluminum (Al), Total** | 0.010% min | Grain refiner for fine austenite grain size. | | **Nitrogen (N)** | Controlled | Optimized to interact with microalloys. | | **Key Characteristic:** | **Low Carbon Equivalent (CE).** Typically ≤ 0.35, ensuring superior cold formability and weldability for a 45 ksi yield strength steel. | | --- ### **4. Physical & Mechanical Properties** The Class 1 Formable designation ensures mechanical properties are tailored for fabrication. | Property | Specification Minimum (ASTM A1011, Grade 45K, Class 1) | Typical Value / Description | | :--- | :--- | :--- | | **Yield Strength (min)** | 45 ksi (310 MPa) | | | **Tensile Strength** | **60 ksi max (415 MPa max)** | **Key Class 1 Feature:** A *maximum* tensile strength is specified to ensure a lower yield-to-tensile ratio (Y/T), which promotes better formability and more uniform deformation. Typically 55-60 ksi. | | **Yield-to-Tensile Ratio** | **Lower than Class 2** | Typically 0.75 - 0.82, indicating good strain distribution during forming. | | **Elongation in 2" (min)** | **Higher than Class 2** (e.g., 22-24% min) | **Key Class 1 Feature.** Guarantees superior ductility for stretching and drawing operations. | | **Plastic Strain Ratio (r̄-value)** | Not typically specified, but generally good | The fine-grained microstructure from microalloying contributes to good deep-drawing ability. | | **Strain Hardening Exponent (n-value)** | Not typically specified, but generally favorable | | | **Modulus of Elasticity** | 29,000 ksi (200 GPa) | | | **Notch Toughness** | **Excellent.** Fine-grained microstructure provides good impact resistance. | | | **Surface Finish** | Standard hot-rolled mill finish. | | --- ### **5. Key Features & Advantages** * **Optimized Strength-Formability Balance:** The core benefit. Delivers 45 ksi yield strength while being explicitly qualified for more demanding forming operations than standard structural HSLA grades. * **Excellent Weldability:** The low carbon equivalent allows for welding with minimal or no preheat in most thicknesses, simplifying fabrication. * **Superior Toughness:** The microalloyed, fine-grained ferrite microstructure provides excellent resistance to brittle fracture. * **Weight Reduction Potential:** The 45 ksi strength allows for down-gauging (using thinner material) compared to conventional steels, reducing part weight and material cost. * **Consistent Performance:** Controlled thermomechanical processing ensures uniform properties coil-to-coil. --- ### **6. Product Applications** ASTM A1011 Grade 45K Class 1 is specified for components requiring both higher strength and significant forming during manufacture. * **Automotive Structural Parts:** Frame rails, engine cradles, seat frames, and crossmembers that require both strength and complex shapes. * **Heavy Equipment Cab & ROPS Structures:** Operator cabins and Roll-Over Protective Structures that need high strength energy absorption and are formed from sheet. * **Agricultural Equipment:** Formed chassis components, fenders, and structural housings for combines and tractors. * **Construction & Mining Equipment:** Formed buckets, access doors, and guards that require durability and shape complexity. * **Material Handling:** Formed components for forklifts, loader arms, and conveyor systems. * **General Fabrication:** Any part where a designer wants a 45 ksi material but is concerned about forming limits of standard HSLA grades. --- ### **7. Fabrication & Processing Notes** * **Forming:** Excellent for cold forming, including bending, roll-forming, and moderate drawing. The lower Y/T ratio and higher elongation provide more uniform deformation and less springback than higher-strength steels. Recommended bend radii are typically 2-3x material thickness. * **Welding:** **Highly weldable.** Use standard low-hydrogen processes (GMAW, FCAW). Preheating is generally not required for thicknesses under 0.75". Use filler metals matching the 45-50 ksi strength level. * **Cutting:** All thermal cutting methods are suitable. Shearing may require higher tonnage than for mild steel. * **Surface Preparation:** Mill scale must be removed by pickling or abrasive blasting for painting or coating. * **Strain Aging:** While microalloyed steels are more resistant, it is good practice to complete forming and welding within a reasonable time if the part is to be painted or coated, to avoid potential for aging effects. --- **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)**. The MTR will confirm the **Grade (45K)** and **Formability Class (Class 1)**. It is crucial to specify **both** the grade and the formability class (e.g., "ASTM A1011, Grade 45K, Class 1 Formable") to ensure receipt of the correct material with the enhanced ductility properties. -:- For detailed product information, please contact sales. -: AK Steel ASTM A 1011, Class 1 Formable, Grade 45K Hot Rolled Carbon Steel, Medium/High Strength Low Alloy Steel (HSLA) Specification Dimensions Size： Diameter 20-1000 mm Length <4594 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 45K 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 45K 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 45K 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 45K 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 1065 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