AK Steel ASTM A 570, Grade 50 Hot Rolled Carbon Steel

AK Steel ASTM A 570, Grade 50 Hot Rolled Carbon Steel, Structural Quality (SQ) Product Information -:- For detailed product information, please contact sales. -: AK Steel ASTM A 570, Grade 50 Hot Rolled Carbon Steel, Structural Quality (SQ) Synonyms -:- For detailed product information, please contact sales. -:

AK Steel ASTM A 570, Grade 50 Hot Rolled Carbon Steel, Structural Quality (SQ) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AK Steel ASTM A570 Grade 50 (SQ) Hot Rolled Carbon Steel** **AK Steel ASTM A570 Grade 50 (Structural Quality - SQ)** is a **high-strength, hot-rolled carbon steel sheet and strip** engineered to deliver **50 ksi (345 MPa) minimum yield strength** for demanding structural applications. This grade represents a specialized extension of the A570 specification, utilizing advanced rolling and chemistry control to achieve strength levels typically associated with High-Strength Low-Alloy (HSLA) steels. It is designed for components requiring **enhanced load capacity and weight reduction** while maintaining the fundamental fabricability of carbon steel. The "SQ" designation confirms its production to standard Structural Quality requirements. --- ## **International Standard & Key Specifications** * **Primary Standard:** **ASTM A570/A570M** - Standard Specification for Steel, Sheet and Strip, Carbon, Hot-Rolled, Structural Quality. * **Quality Designation:** **Structural Quality (SQ)** - Standard commercial quality for structural applications. * **Governance:** Manufactured to standard hot-rolled mill practices with enhanced process controls. Dimensional tolerances reference **ASTM A568**. * **Technical Context:** While ASTM A570 officially lists Grades 30-45, **Grade 50 represents a proprietary extension** by specific producers like AK Steel. In broader industry practice, 50 ksi hot-rolled sheet is more commonly specified under **ASTM A1011 (HSLAS Grade 50)** or **ASTM A572 Grade 50**. * **Industry Alternatives:** For guaranteed 50 ksi properties with optimal weldability, **ASTM A1011 Grade 50** (HSLA) is the prevalent specification. --- ## **Chemical Composition (Weight %, typical)** To achieve 50 ksi yield strength while maintaining adequate weldability, this grade employs carefully optimized carbon-manganese balance with potential microalloy additions. | Element | Composition (%) | Role in Performance | | :--- | :--- | :--- | | **Carbon (C)** | 0.22 - 0.25 max | Primary strengthener; controlled at upper specification limits. | | **Manganese (Mn)** | 1.00 - 1.35 max | Critical for strength enhancement and transformation control. | | **Phosphorus (P)** | 0.04 max | Impurity, tightly controlled. | | **Sulfur (S)** | 0.05 max | Impurity, controlled for weldability. | | **Silicon (Si)** | 0.15 - 0.30 | Deoxidizer and solid solution strengthener. | | **Microalloys (V/Nb)** | 0.01 - 0.05 (may be added) | Often required for consistent 50 ksi yield via precipitation strengthening. | | **Carbon Equivalent (CE)** | **~0.40 - 0.48** | High; requires careful welding procedure control. | **Production Note:** Consistent achievement of 50 ksi yield in hot-rolled condition typically necessitates either: 1. Operating at the absolute upper limits of carbon/manganese ranges, or 2. Strategic addition of microalloying elements (vanadium/niobium) within permissible limits. --- ## **Typical Physical & Mechanical Properties (Hot-Rolled, Grade 50)** | Property | Value / Description | | :--- | :--- | | **Tensile Strength** | 480 - 655 MPa (70,000 - 95,000 psi) | | **Yield Strength (min)** | **345 MPa (50,000 psi)** | | **Elongation in 2-in (50 mm) (min)** | **18%** | | **Modulus of Elasticity** | ~200 GPa (29 x 10⁶ psi) | | **Density** | ~7.85 g/cm³ (0.284 lb/in³) | | **Formability** | **Moderate to Fair.** Suitable for simple bending operations. Minimum bend radius typically **2-3 × material thickness**. Significant springback expected. | | **Weldability** | **Requires strict procedures.** High carbon equivalent necessitates preheat and low-hydrogen consumables for most applications. | --- ## **Product Applications** AK Steel A570 Grade 50 (SQ) is specified for heavy-duty structural applications where maximum strength from conventional hot-rolled carbon steel is required. **Primary Industries and Products:** 1. **Heavy Structural Systems:** * **Primary load-bearing beams and columns** in industrial structures * **Heavy-duty purlin and girt systems** for long-span buildings * **Equipment support frames and platforms** 2. **Transportation & Heavy Equipment:** * **Heavy truck chassis components and frame rails** * **Trailer main beams and structural members** * **Construction equipment frames and mounting brackets** 3. **Material Handling & Storage:** * **Extra-heavy-duty storage rack systems** * **Crane runway beams and support structures** * **Heavy industrial platforms and walkways** 4. **Construction & Infrastructure:** * **Heavy formwork and shoring systems** * **Bridge components and temporary structures** * **Heavy-duty sign and signal supports** --- ## **Advantages and Critical Fabrication Considerations** * **Advantages:** * **High Strength:** 50 ksi minimum yield provides maximum strength in carbon steel category * **Material Efficiency:** Enables lighter designs or higher load capacity * **Cost Optimization:** Potentially more economical than some HSLA alternatives * **Proven Performance:** Established material with predictable characteristics * **Critical Fabrication Considerations:** * **Welding Requirements:** **High carbon equivalent demands careful welding control.** Mandatory **preheat of 250-350°F (120-175°C)** for thicknesses >1/8" (3 mm). **Low-hydrogen processes essential** (E7018 electrodes, ER70S-6 wire with proper shielding). * **Limited Formability:** Reduced ductility compared to lower-strength grades. Complex forming operations risk cracking. * **Surface Preparation:** Mill scale must be thoroughly removed for coating adhesion. **Pickled and Oiled (P&O)** condition strongly recommended. * **Notch Sensitivity:** High strength increases susceptibility to crack initiation at sharp notches or weld defects. * **Alternative Materials:** For better weldability and formability at 50 ksi strength, **ASTM A1011 HSLAS Grade 50** or **ASTM A607 Grade 50** (HSLA steels) provide superior fabricability with lower carbon content. * **Quality Verification:** Require certified test reports to confirm 50 ksi yield strength is consistently achieved. **In summary, AK Steel ASTM A570 Grade 50 (SQ) represents a specialized high-strength carbon steel option for applications requiring 50 ksi yield strength. While offering potential cost advantages, it presents significant fabrication challenges in welding and forming that must be carefully managed. For most applications requiring 50 ksi strength with good weldability, industry-standard HSLA grades (A1011 Grade 50 or A572 Grade 50) generally provide a more balanced and reliable solution.** -:- For detailed product information, please contact sales. -: AK Steel ASTM A 570, Grade 50 Hot Rolled Carbon Steel, Structural Quality (SQ) Specification Dimensions Size： Diameter 20-1000 mm Length <4559 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 570, Grade 50 Hot Rolled Carbon Steel, Structural Quality (SQ) Properties -:- For detailed product information, please contact sales. -:

Applications of AK Steel ASTM A 570, Grade 50 Hot Rolled Carbon Steel, Structural Quality (SQ) -:- For detailed product information, please contact sales. -: Chemical Identifiers AK Steel ASTM A 570, Grade 50 Hot Rolled Carbon Steel, Structural Quality (SQ) -:- For detailed product information, please contact sales. -:

Packing of AK Steel ASTM A 570, Grade 50 Hot Rolled Carbon Steel, Structural Quality (SQ) -:- 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 1030 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