AISI 8655H Steel

AISI 8655H Steel Product Information -:- For detailed product information, please contact sales. -: AISI 8655H Steel Synonyms -:- For detailed product information, please contact sales. -:

AISI 8655H Steel Product Information -:- For detailed product information, please contact sales. -: ### **Product Datasheet: AISI 8655H Hardenability-Controlled Alloy Steel** --- #### **1. Material Overview** **AISI 8655H** is a **medium-carbon, nickel-chromium-molybdenum (Ni-Cr-Mo) alloy steel** supplied under a **controlled hardenability specification**, as denoted by the **"H" suffix**. It shares the fundamental composition of standard AISI 8655 but is produced to meet specific **end-quench hardenability (Jominy test) band requirements** defined by SAE J1268. This grade represents the **premium execution** of the 86xx series, designed for applications where **predictable and consistent through-hardening in medium to large sections is absolutely critical**. It ensures uniform mechanical properties from surface to core, making it ideal for high-integrity, safety-critical components. #### **2. Key Material Concept: The "H" Guarantee** The **"H" designation** is the defining feature that differentiates this from standard 8655: - **Guaranteed Hardenability Band:** The steel's hardenability, as measured by the Jominy end-quench test, must fall within a predefined range published in SAE J1268. This ensures predictable depth of hardening and transformation behavior across different production lots. - **Chemical Composition as a Means, Not an End:** While the base chemistry is similar to 8655, the allowable ranges for elements like carbon, manganese, nickel, and chromium are **wider**. This allows the steelmaker to "tune" the composition to consistently hit the target hardenability band, rather than a narrow chemical bullseye. - **Result:** Manufacturers obtain a material with **eliminated heat treatment variability**, enabling optimized quench & temper cycles, reduced scrap rates, and guaranteed core properties in finished parts. #### **3. International Standard & Cross-References** - **Governing Standard:** **ASTM A304** - Standard Specification for Carbon and Alloy Steel Bars Subject to End-Quench Hardenability Requirements. - **Composition Reference:** **SAE J404** (Chemical Compositions of SAE Alloy Steels). - **Hardenability Band Standard:** **SAE J1268** (Hardenability Bands for Carbon and Alloy H-Steels). - **UNS Designation:** **H86550** - **Common Procurement Specification:** **ASTM A304, Grade 8655H**. - **European Equivalent Concept:** Similar to steels supplied to **EN 10083-1/4** with specified hardenability values (e.g., Jominy values for 34CrNiMo6), but no direct "H"-system equivalent exists. - **Japanese Equivalent:** No direct JIS equivalent for the H-band system. #### **4. Chemical Composition (% by Weight, per SAE J1268 for H-Steels)** *Ranges are wider than for non-H 8655 to facilitate hardenability band control.* | Element | Content Range (%) | Key Role & "H" Band Implication | | :--- | :--- | :--- | | **Carbon (C)** | **0.50 – 0.60** | Primary hardening element. The range allows adjustment to center the hardenability curve. | | **Manganese (Mn)** | **0.70 – 1.05** | Major hardenability enhancer. Its wider range is a primary control variable for the band. | | **Phosphorus (P)** | **≤ 0.035** | Impurity; kept low. | | **Sulfur (S)** | **≤ 0.040** | Impurity; kept low. | | **Silicon (Si)** | **0.15 – 0.35** | Deoxidizer; strengthens ferrite. | | **Nickel (Ni)** | **0.35 – 0.75** | **Crucial for toughness.** Its range is managed to ensure consistent core toughness within the band. | | **Chromium (Cr)** | **0.35 – 0.65** | Enhances hardenability and wear resistance. Range ensures band compliance. | | **Molybdenum (Mo)** | **0.15 – 0.25** | **Critical:** Provides deep hardenability, grain refinement, and **resists temper embrittlement**—a key advantage for achieving high toughness after tempering. | | **Iron (Fe)** | **Balance** | Base metal. | #### **5. Typical Physical & Mechanical Properties** **A. Physical Properties:** - **Density:** 7.85 g/cm³ (0.284 lb/in³) - **Modulus of Elasticity:** 205 GPa (29.7 x 10⁶ psi) - **Poisson’s Ratio:** 0.29 **B. Hardenability Band (Per SAE J1268 for 8655H):** *Example values from the standard band (actual certification required):* - **At Jominy Distance J4 (6.35mm):** 50-58 HRC - **At Jominy Distance J10 (15.9mm):** 42-52 HRC - **At Jominy Distance J16 (25.4mm):** 36-47 HRC *This data allows precise prediction of as-quenched hardness at any point in an actual part based on its cooling rate.* **C. Achievable Mechanical Properties (After Quench & Temper):** *For a properly heat-treated 50mm (2") round, oil quenched and tempered:* - **Tensile Strength:** 1000 – 1250 MPa (145 – 181 ksi) - **Yield Strength (0.2% Offset):** 850 – 1100 MPa (123 – 160 ksi) - **Elongation:** 13% – 18% - **Reduction in Area:** 50% – 60% - **Impact Toughness (Charpy V-notch):** **50 – 100 J (37 – 74 ft-lb)** at room temperature – exceptional for this strength level. - **Core Hardness Consistency:** Minimal variation from surface to center in sections within its hardenability capacity. #### **6. Processing & Fabrication Characteristics** - **Hardenability Performance:** **Excellent and Guaranteed.** The primary reason for selection. Provides reliable through-hardening for sections up to **~100-125 mm (4-5 inches)** in diameter with a vigorous oil quench. - **Machinability (Annealed):** **Fair.** Similar to standard 8655. The guaranteed "H" grade often comes with better consistency, aiding predictable tool life. - **Weldability:** **Poor.** Identical cautions apply as for standard 8655. Requires stringent preheat, low-hydrogen processes, and mandatory PWHT. Not recommended for primary welded structures. - **Heat Treatment Consistency:** **Superior.** The "H" band eliminates lot-to-lot variation, allowing for fixed, validated furnace cycles that minimize distortion and guarantee properties. #### **7. Primary Applications** AISI 8655H is specified for **critical, high-stress components** where performance uniformity is non-negotiable: - **Heavy-Duty Automotive & Truck:** **Critical axle shafts** (front/rear), **high-performance crankshafts**, **transmission gears**, and **heavy-duty suspension components**. - **Mining & Construction Equipment:** **Final drive gears**, **track rollers**, **shovel dipper arms**, and **crusher shafts**. - **Oil & Gas Industry:** **Large drill collar subs**, **mud pump crankshafts**, and **high-pressure wellhead components**. - **Power Generation:** **Large gear blanks** for wind turbine gearboxes, **generator shafts**, and **turbo-machinery components**. - **Defense & Aerospace (Landing Gear):** **Landing gear components**, **armored vehicle torsion bars**, and other high-integrity structural parts. - **Large Industrial Fasteners:** **Ultra-high-strength bolts** (ASTM A490, SAE Grade 8+) for critical structural connections. #### **8. Available Forms & Procurement** - **Common Forms:** Hot-rolled or forged rounds, squares, and billets. Typically supplied in the **annealed or normalized & tempered condition**. - **Critical Procurement Note:** Must be ordered explicitly to **ASTM A304, Grade 8655H**. - **Mandatory Certification:** The mill's **Certified Material Test Report (CMTR) must include both chemical analysis and the actual Jominy hardenability test results** proving compliance with the SAE J1268 band for 8655H. --- **Disclaimer:** The successful application of 8655H depends on **using the provided Jominy hardenability data to model the quenching process** for the specific part geometry. The "H" designation guarantees the *response to quenching*, not the final tempered properties, which are set by the tempering cycle. This is a premium material where the cost of failure or inconsistency justifies the specification. Always collaborate with the steel supplier's metallurgical team and your heat treater for critical components. -:- For detailed product information, please contact sales. -: AISI 8655H Steel Specification Dimensions Size： Diameter 20-1000 mm Length <5184 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 8655H Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 8655H Steel -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 8655H Steel -:- For detailed product information, please contact sales. -:

Packing of AISI 8655H Steel -:- 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 1655 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