GB/T 45981.2-2025 in English
VALIDHeavy casting and forging for heavy-duty gas turbine—Part 2：Superalloy die forgings
- Issued on:2025-08-01
- Implemented on:2026-02-01
- File Format:PDF
- Delivery:Via email within 5 business days
$306.00
| Standard No: | GB/T 45981.2-2025 |
| Document status: | VALID |
| Title in English: | Heavy casting and forging for heavy-duty gas turbine—Part 2：Superalloy die forgings |
| Title in Chinese: | 重型燃气轮机用大型铸锻件 第2部分：高温合金模锻件 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 5 business days |
| Issued on: | 2025-08-01 |
| Implemented on: | 2026-02-01 |
| ICS Classification: | 77.140.85-Iron and steel forgings |
| Chinese Classification: | J32-Forging and pressing |
| Professional Classification: | GB-National Standard |
| Related Keywords: | heavy-duty gas turbine part
heavy-duty gas turbine industry heavy-duty gas turbine sector heavy-duty gas turbines forging process |
| Related Topics: | large gas mixture
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《GB/T 45981.2-2025重型燃气轮机用大型铸锻件 第2部分：高温合金模锻件》由TC506（全国大型铸锻件标准化技术委员会）归口，主管部门为中国机械工业联合会。
Introduction
Background of Standard Formulation and Technological Evolution
As the core power equipment of the energy efficient conversion and clean utilization system, the technological development level of heavy-duty gas turbines is directly related to the national energy security and green development strategy. With the rapid development of my country's heavy-duty gas turbine industry, the requirements for key component materials are increasing. The formulation of GB/T 45981.2-2025 is precisely to standardize the manufacturing process of large-scale high-temperature alloy forgings for heavy-duty gas turbines and improve product quality and reliability.
Technical Specifications for Core Materials
This standard focuses on standardizing three key high-temperature alloy materials: GH4169, GH4706 and GH4698. These materials undertake the manufacturing tasks of key components in heavy-duty gas turbines and need to maintain excellent mechanical properties and corrosion resistance under high temperature, high pressure and high stress environments.
| Material brand | Applicable temperature range (℃) | Main characteristics | Application parts |
|---|---|---|---|
| GH4169 | ≤650 | Excellent high temperature strength and oxidation resistance | Disc forgings, tie rod forgings |
| GH47 06 | ≤650 | Good endurance and creep resistance | Rim components |
| GH4698 | ≤750 | Excellent thermal fatigue performance | High-temperature turbine components |
Chemical composition control requirements
The standard strictly specifies the chemical composition of the three high-temperature alloys to ensure the basic performance of the materials. Taking GH4169 as an example, its nickel content is required to be controlled within 50.00%-55.00%, molybdenum content within 2.80%-3.30%, and niobium content within 4.75%-5.50%. Precise control of these elements is crucial to the material's high-temperature performance.
Key technologies of manufacturing process
Smelting process
The standard specifies the smelting methods of different alloys: GH4169 adopts vacuum induction melting + vacuum arc furnace remelting and other processes; GH4706 adopts vacuum induction melting + electroslag remelting + vacuum arc furnace remelting; GH4698 adopts vacuum induction melting + vacuum arc furnace remelting. These processes ensure the purity and structural uniformity of the material.
Forging process
During the forging process, the total forging ratio of GH4169, GH4706, and GH4698 alloy bars should be ≥4 to ensure that there are no shrinkage cavities and severe segregation in the forging body. The designed deformation requirement in each process of disc forging is not less than 30% to ensure structural uniformity and performance consistency.
Comparative analysis of heat treatment systems
| Material grade | Solution treatment | Aging treatment | Cooling method |
|---|---|---|---|
| GH4169 | 720℃±5℃，8h | 620℃±5℃，8h | Furnace cooling at 55℃/h |
GH4706Nondestructive Testing StandardsUltrasonic testing uses five levels of acceptance criteria, ranging from Level 1 (0.8mm equivalent flat-bottom hole) to Level 5 (3.2mm equivalent flat-bottom hole), to meet the quality requirements of different parts. During the inspection process, attention should also be paid to the spacing and length limits of multiple defect indications and long strip defect indications. Quality Control and Inspection RulesThe standard stipulates that forgings should be inspected and accepted piece by piece. If the chemical composition analysis results are unqualified, the forgings from the furnace are unqualified. If the mechanical properties are unqualified, re-inspection and repeated heat treatment are allowed, but repeated heat treatment can only be performed once. Implementation Recommendations and PrecautionsManufacturing Process ControlIt is recommended that manufacturers establish a comprehensive quality traceability system to monitor the entire process from raw material smelting to the final product. Special attention should be paid to the control of forging temperature and deformation to ensure structural uniformity. Improving Testing TechnologyIt is recommended to adopt advanced nondestructive testing technologies, such as phased array ultrasonic testing and computed tomography, to improve defect detection rates and accuracy. Technical Document ManagementPurchasers should clearly specify all technical requirements in the order contract, and suppliers must provide complete quality certificates, including key information such as smelting methods, heat treatment systems, and inspection results. Standardization Significance and Development OutlookThe implementation of GB/T 45981.2-2025 will effectively promote technological progress and quality improvement in my country's heavy-duty gas turbine industry. With the continuous development of new materials and new processes, the standard will continue to be revised and improved, providing technical support for the high-quality development of my country's energy equipment manufacturing industry. In the future, it is recommended to focus on the application of additive manufacturing technology in the manufacture of high-temperature alloy components and the innovative application of intelligent detection technology in quality monitoring, continuously enhancing my country's international competitiveness in the heavy-duty gas turbine sector. Sample only — not a preview of GB/T 45981.2-2025
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