AISI 1340H Steel Rod/Bar

AISI 1340H Steel Rod, normalized at 870°C (1600°F), air cooled, 100 mm (4 in.) round Product Information -:- For detailed product information, please contact sales. -: AISI 1340H Steel Rod, normalized at 870°C (1600°F), air cooled, 100 mm (4 in.) round Synonyms -:- For detailed product information, please contact sales. -:

AISI 1340H Steel, normalized at 870°C (1600°F), air cooled, 100 mm (4 in.) round Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: AISI 1340H Steel, Normalized at 870°C (1600°F), Air Cooled, 100 mm (4 in.) Round Bar** **Overview** AISI 1340H steel in the **normalized at 870°C (1600°F) and air cooled** condition represents the highest level of material control for this medium-carbon manganese alloy steel in an extra-large **100 mm (4 in.) diameter**. The **"H"** (hardenability) designation is not merely beneficial but **essential** at this cross-section, as it guarantees the steel's transformation behavior within strict SAE J1268 limits. For a diameter of this magnitude, normalization is a critical stabilization process to homogenize severe segregation and relieve massive internal stresses from rolling. The H-grade assurance provides engineers with the unique capability to **accurately model and predict the through-thickness microstructure and property gradient**, making this the definitive choice for colossal, high-value components where failure from material inconsistency is unacceptable. **Key Features & Advantages** * **Predictable Property Gradient in Massive Sections:** The core value of the H-grade for a 100 mm bar is the guaranteed, calculable gradient of microstructure (fine pearlite at surface to coarse pearlite/bainite at core) and hardness. This allows for precise finite element analysis (FEA) and design based on known material behavior, not estimates. * **Essential Homogenization & Stress Relief:** The primary purpose of normalizing this large section is to create a **stable, uniform, and stress-relieved blank**. The H-grade ensures this outcome is consistent, preventing catastrophic distortion during machining and unpredictable performance in service. * **Foundation for Reliable Machining:** While machining is heavy and demanding, starting with an H-grade normalized bar ensures the material's hardness and structure are exactly as modeled. This allows for optimized, stable machining parameters and predictable tool life across the entire component and across multiple material lots. * **Verifiable Quality for Critical Applications:** The provision of Jominy hardenability data with the Certified Mill Test Report (CMTR) offers unparalleled traceability and proof of conformance, which is mandatory for components in regulated industries such as energy, defense, and heavy capital equipment. * **Risk Mitigation at Scale:** The premium for 1340H over standard 1340 is insignificant compared to the cost of a failed 100 mm diameter shaft, gear blank, or forging that could cause millions in downtime, repair, or liability. --- ### **1. Chemical Composition & Hardenability Conformance** The chemistry is tightly controlled to achieve a specific hardenability band. **For a 100 mm section, the Jominy hardenability curve is the single most important material specification.** | Element | AISI 1340H Range (%) | Key Function in Large Sections | | :--- | :--- | :--- | | **Carbon (C)** | 0.37 – 0.44 | Provides baseline strength. Its controlled level ensures predictable core strength and response to surface hardening. | | **Manganese (Mn)** | 1.60 – 2.00 | **The Critical Element.** This high, controlled manganese content is what makes 1340H viable at 100 mm. It provides the hardenability "reach" to influence microstructure deeper into the core during air cooling, preventing an excessively weak and soft center. | | **Phosphorus (P)** | ≤ 0.035 (max) | Residual, minimized for transverse toughness. | | **Sulfur (S)** | ≤ 0.040 (max) | Residual, kept low. | | **Silicon (Si)** | 0.15 – 0.35 | Deoxidizer and solid solution strengthener. | | **Iron (Fe)** | Balance | Base element. | **Hardenability Specification:** Produced to a specific **H-Band** per **SAE J1268**. The **CMTR must include the full Jominy end-quench hardenability curve.** **Key International Standard Equivalents:** * **UNS:** H13400 * **AISI/SAE:** 1340H (SAE J1868) * **ASTM:** **A304** (Standard for Hardenability Steel Bars) * **Quality Philosophy:** Aligns with **EN 10268** and similar standards requiring verified hardenability. --- ### **2. Typical Physical & Mechanical Properties (Normalized at 870°C / 1600°F, 100 mm dia.)** *The properties are dominated by the slow cooling rate at the core of a 100 mm bar. The H-grade defines the bounds of this gradient.* | Property | Typical Value / Description | Engineering Implication | | :--- | :--- | :--- | | **Density** | 7.85 g/cm³ | - | | **Tensile Strength** | 560 – 720 MPa (81 – 104 ksi) | Core strength is at the lower end. Design must account for this gradient. | | **Yield Strength (0.2% Offset)** | 320 – 480 MPa (46 – 70 ksi) | Core yield strength is significantly lower than surface. | | **Elongation (in 50mm)** | 15% – 20% | - | | **Reduction of Area** | 30% – 45% | - | | **Brinell Hardness (HB)** | **175 – 215** | **Predictable Gradient:** Surface: ~200-215 HB, Mid-Radius: ~185-200 HB, Core: ~175-190 HB. | | **Core Microstructure** | Coarse Pearlite + Ferrite (possibly with some upper bainite). | This is a **normalized** structure for this size, not an annealed one. It has good toughness. | | **Machinability** | Moderate to Difficult (~40-45% of 1212). Consistency allows for stable heavy machining. | | --- ### **3. Product Applications** AISI 1340H normalized 100 mm round bar is specified for the most critical, large-scale components across heavy industry. * **Mega-Shafting for Heavy Industry:** Main turbine rotors, generator shafts, large marine propulsion shafts, and rolling mill work rolls. * **Critical Gear Blanks for Mining & Energy:** Stock for the largest gears in ball mills, draglines, and wind turbine gearboxes where core integrity is as vital as surface hardness. * **Forging Blanks for Ultra-High-Strength Parts:** Mandatory starting stock for giant open-die forgings like pressure vessel shells, large crankshafts, and structural components for nuclear or hydroelectric applications. * **Back-Up Rolls & Large Cylinders:** For steel mills and heavy presses where uniformity prevents premature spalling or failure. * **Defense & Aerospace Primary Structures:** Large landing gear components, armament trunnions, and other safety-critical parts requiring full material certification. * **Any application where the component cost, system criticality, or consequence of failure justifies the highest level of material predictability.** --- ### **4. Heat Treatment Philosophy & the H-Grade Imperative** * **Normalization as a Final Bulk Treatment:** For a 100 mm diameter, normalization is typically the **final bulk heat treatment**. Attempting to through-harden to martensite is impractical and dangerous (extreme quench severity required, high risk of cracking). The H-grade defines the **as-normalized** condition as a reliable engineering state. * **Surface Hardening is the Complement:** Components made from this material often receive **flame or induction hardening** on wear surfaces. The predictable, tough normalized core provided by the H-grade is the perfect substrate for a hard case. * **The Jominy Curve as a Design Blueprint:** For this diameter, the Jominy data is used to: 1. **Accurately map the as-normalized hardness gradient** for stress and load modeling. 2. **Verify the material's capability** to meet the design's core property requirements *in its normalized state*. 3. **Disqualify unsuitable lots** before they enter expensive manufacturing. * **The Non-Negotiable Comparison:** * **Standard AISI 1340 (100mm):** Effectively **unqualified for critical engineering use**. The risk of segregation, unpredictable core properties, and hidden stress is unacceptably high. * **AISI 1340H (100mm):** The **only responsible choice** for a designed component. It provides a verified, stable, and predictable material condition. * **Mandatory Process & Documentation:** * **Stress Relieving:** After heavy rough machining, a **subsequent stress relief** (e.g., 595-650°C) is **strongly recommended** to ensure dimensional stability during final machining. * **Certification:** The **CMTR with Jominy data is the material's passport**. It is required for design validation, manufacturing process qualification (e.g., NADCAP, ASME), and provides legal and technical traceability for the life of the component. -:- For detailed product information, please contact sales. -: AISI 1340H Steel, normalized at 870°C (1600°F), air cooled, 100 mm (4 in.) round Specification Dimensions Size： Diameter 20-1000 mm Length <5030 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. -: AISI 1340H Steel, normalized at 870°C (1600°F), air cooled, 100 mm (4 in.) round Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 1340H Steel Rod, normalized at 870°C (1600°F), air cooled, 100 mm (4 in.) round -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 1340H Steel Rod, normalized at 870°C (1600°F), air cooled, 100 mm (4 in.) round -:- For detailed product information, please contact sales. -:

Packing of AISI 1340H Steel Rod, normalized at 870°C (1600°F), air cooled, 100 mm (4 in.) round -:- 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 Rod 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 1501 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