ASTM A470-8 1Cr-1Mo-0.25V Steel Capillary FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8)

ASTM A470-8 1Cr-1Mo-0.25V Steel Capillary FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8) Product Information -:- For detailed product information, please contact sales. -: ASTM A470-8 1Cr-1Mo-0.25V Steel Capillary FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8) Synonyms -:- For detailed product information, please contact sales. -:

ASTM A470-8 1Cr-1Mo-0.25V STEEL FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8) Product Information -:- For detailed product information, please contact sales. -: ## **Product Datasheet: ASTM A470-8 Class 8 1Cr-1Mo-0.25V Steel Forgings for Turbine Rotors and Shafts** **Product Overview** ASTM A470-8 Class 8 is a high-strength, vacuum-treated **1% Chromium - 1% Molybdenum - 0.25% Vanadium (1Cr-1Mo-0.25V) alloy steel** specifically engineered for **forged turbine rotors and shafts** operating in high-temperature steam environments. This grade represents a premium class of rotor steel, designed to deliver exceptional **creep strength, fracture toughness, and high-cycle fatigue resistance** under the extreme centrifugal and thermal stresses encountered in steam turbines. The addition of vanadium provides significant precipitation strengthening and refines the microstructure, making it suitable for the most demanding sections of intermediate and high-pressure turbine rotors. It is a critical material for modern, efficient fossil-fuel and nuclear power generation. **Key International Standards** * **Primary Standard:** **ASTM A470 / A470M** - Standard Specification for Vacuum-Treated Carbon and Alloy Steel Forgings for Turbine Rotors and Shafts. * **Governing Specification:** This product conforms to the requirements for **Class 8** within ASTM A470, denoting the specific 1Cr-1Mo-0.25V chemistry and associated mechanical properties. * **ASME Designation:** **SA-470 Class 8** - The ASME Boiler and Pressure Vessel Code designation. * **Mandatory Manufacturing Process:** **Vacuum degassing** is required to achieve extremely low levels of hydrogen, oxygen, and nitrogen, ensuring superior internal soundness and resistance to hydrogen embrittlement and temper embrittlement. * **Heat Treatment:** Forgings are supplied in a **quenched and tempered (Q&T)** condition, followed by a **stress relief heat treatment**. The exact thermal cycle is critical and proprietary to the forger to achieve the required property profile. **Chemical Composition (Weight % - ASTM A470 Class 8 Requirements)** | Element | ASTM A470 Class 8 Requirement | Typical Range / Aim | | :--- | :--- | :--- | | **Carbon (C)** | 0.20 - 0.30% | 0.22 - 0.28% | | **Manganese (Mn)** | 0.60 - 0.90% | 0.70 - 0.85% | | **Phosphorus (P)** | 0.012% max | ≤ 0.008% | | **Sulfur (S)** | 0.012% max | ≤ 0.006% | | **Silicon (Si)** | 0.15 - 0.35% | 0.20 - 0.30% | | **Chromium (Cr)** | **0.90 - 1.25%** | 1.00 - 1.20% | | **Molybdenum (Mo)** | **1.00 - 1.30%** | 1.05 - 1.20% | | **Vanadium (V)** | **0.20 - 0.30%** | 0.22 - 0.28% | | **Nickel (Ni)** | 0.50% max (residual) | ≤ 0.25% | | **Copper (Cu)** | 0.15% max (residual) | ≤ 0.10% | | **Tin (Sn)** | 0.015% max | ≤ 0.010% | | **Antimony (Sb)** | 0.0015% max | ≤ 0.0010% | | **Arsenic (As)** | 0.020% max | ≤ 0.015% | **Physical & Mechanical Properties** *Properties are location-dependent (surface, 1/4T, center) and are stringently tested. Values are typical for a mid-size rotor.* | Property | Typical Requirement (Surface / Body) | Key Performance Driver | | :--- | :--- | :--- | | **Tensile Strength** | 105 - 125 ksi (725 - 860 MPa) | High strength to withstand centrifugal loads. | | **Yield Strength (0.2% Offset)** | 90 ksi (620 MPa) min | Ensures no permanent deformation under stress. | | **Elongation (%)** | 16% min | Maintains ductility despite high strength. | | **Reduction of Area (%)** | 45% min | Critical for fracture resistance. | | **Charpy V-Notch Toughness (FATT)** | **FATT50 ≤ 200°F (93°C) typical.**
Upper Shelf Energy ≥ 60 ft-lb. | **Fracture Appearance Transition Temperature (FATT)** is a key specification. Ensures rotor remains ductile at operating temperatures. | | **Creep Rupture Strength** | Defined per long-term testing (e.g., 100,000 hr life at design temp/pressure). | Vanadium carbides provide exceptional long-term creep resistance at temperatures up to ~1050°F (566°C). | | **Key Feature** | **High-Temperature Rotor Integrity:** Combines high tensile/creep strength with guaranteed **fracture toughness** (via FATT control) to ensure safe, reliable operation for decades under the combined assault of stress, heat, and steam. | **Product Applications** ASTM A470 Class 8 forgings are used exclusively for the most critical rotating components in large steam turbines. * **High-Pressure (HP) & Intermediate-Pressure (IP) Turbine Rotors:** For the high-temperature, high-stress sections of utility and industrial steam turbines. * **Turbine Generator Rotors (for smaller units).** * **Turbine Shafts and Spindles** requiring high strength and creep resistance. **Advantages & Fabrication Notes** * **Unmatched Property Uniformity:** Vacuum degassing and advanced forging practices ensure exceptional homogeneity, minimizing property scatter which is vital for rotor dynamics and life prediction. * **Resistance to Temper Embrittlement:** The extremely low levels of residual elements (P, Sn, Sb, As) are specified to minimize susceptibility to temper embrittlement during long-term service in the critical temperature range (700-1100°F / 371-593°C). * **Superior Creep and Fatigue Performance:** The synergistic effect of Cr, Mo, and V creates a stable microstructure of fine carbides that resist coarsening, providing excellent long-term creep and low-cycle fatigue strength. * **Complex, Proprietary Manufacturing:** Involves electric furnace melting, ladle refining, vacuum degassing, ingot casting, heavy forging under strict controls, and a precisely defined sequence of heat treatments (austenitizing, quenching, tempering, stress relieving). * **Non-Destructive Examination (NDE):** Subject to the most stringent NDE, including ultrasonic testing (UT) from multiple directions, magnetic particle inspection (MPI), and often advanced techniques like bore ultrasonic inspection for hollow rotors. **Disclaimer:** This datasheet describes a **specialized, high-integrity forging product** governed by a detailed standard. Procurement of A470-8 Class 8 forgings is a major capital project undertaken directly with a limited number of qualified heavy forge shops worldwide. Specifications will include not only chemistry and mechanical properties but also **FATT requirements, ultrasonic acceptance criteria, heat treatment charts, and residual stress limits**. All design, material selection, and manufacturing oversight must be performed by engineers specializing in rotating equipment. The properties and long-term behavior are validated through extensive testing, including simulated service condition tests. This material is not used for general fabrication. -:- For detailed product information, please contact sales. -: ASTM A470-8 1Cr-1Mo-0.25V STEEL FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8) Specification Dimensions Size： Diameter 20-1000 mm Length <4700 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. -: ASTM A470-8 1Cr-1Mo-0.25V STEEL FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8) Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A470-8 1Cr-1Mo-0.25V Steel Capillary FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8) -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A470-8 1Cr-1Mo-0.25V Steel Capillary FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8) -:- For detailed product information, please contact sales. -:

Packing of ASTM A470-8 1Cr-1Mo-0.25V Steel Capillary FORGINGS FOR TURBINE ROTORS AND SHAFTS (ASTM A470-8) -:- 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 Capillary 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 1171 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