GB/T 45857-2025 in English
VALIDTubular cored electrodes for electrogas welding
- Issued on:2025-08-01
- Implemented on:2025-11-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$262.00
| Standard No: | GB/T 45857-2025 |
| Document status: | VALID |
| Title in English: | Tubular cored electrodes for electrogas welding |
| Title in Chinese: | 气电焊用药芯焊丝 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 1~3 business days |
| Issued on: | 2025-08-01 |
| Implemented on: | 2025-11-01 |
| ICS Classification: | 25.160.20-Welding consumables |
| Chinese Classification: | J33-Welding and cutting |
| Professional Classification: | GB-National Standard |
| Related Keywords: | welding wire
welding wire tensile strength code scientific welding wire model compilation method self-shielded welding wire welding wire characteristics |
| Related Topics: | electric welding
Flux cored welding wire |
《GB/T 45857-2025气电焊用药芯焊丝》由TC55（全国焊接及相关工艺标准化技术委员会）归口，TC55SC1（全国焊接标准化技术委员会焊接材料分会）执行，主管部门为国家标准委。
Introduction
Standard Development Background and Technological Evolution
The release of the national standard GB/T 45857-2025, "Flux-cored Wire for Gas-Electrode Welding," marks a further improvement in my country's welding material standardization system. This standard, proposed by the National Technical Committee for Welding Standardization (SAC/TC55) and jointly drafted by 17 organizations including Tianjin Jinqiao Welding Materials Group Co., Ltd., will be officially implemented in 2025.
Gas-electric welding, as a highly efficient welding method, is widely used in shipbuilding, pressure vessels, steel structures, and other fields. This standard establishes a comprehensive set of technical specifications for flux-cored wire for gas-shielded and self-shielded gas-electric welding, requiring a minimum weld metal tensile strength of at least 430 MPa.
Key Points of Core Technology Innovation
This standard has achieved a number of innovative breakthroughs in technical content:
| Technical Dimension | Innovative Content | Technical Significance |
|---|---|---|
| Model Compilation System | Seven-part code system covering mechanical properties, welding methods, positions, shielding gas and chemical composition | Achieve accurate identification and classification management of welding wire properties |
| Impact toughness requirements | Introduction of optional code "U", and the impact absorption energy requirement is increased to 47J | Meet the welding needs of high-altitude and cold areas and special working conditions |
| Chemical composition control | 9 chemical composition classifications, including special alloy series such as M2T and N1M | Provide a variety of material options to adapt to different application scenarios |
| Detection method | X-ray inspection acceptance level adopts Level 1 standard in GB/T37910.1-2019 | Improve the accuracy and reliability of weld quality inspection |
Detailed explanation of welding wire model compilation
This standard establishes a scientific welding wire model compilation method, which fully describes the welding wire characteristics through seven parts:
Case analysis: Taking T49N3M2T-U model as an example:
- T: Indicates flux-cored wire
-
| Tensile Strength Code | Tensile Strength Range (MPa) | Yield Strength (MPa) | Elongation (%) | Applicable Fields |
|---|---|---|---|---|
| 43 | 430-600 | ≥280 | ≥22 | General steel structure, building frame |
| 49 | 490-670 | ≥355 | ≥20 | Shipbuilding, Bridge Engineering |
| 55 | 550-740 | ≥420 | ≥18 | Pressure vessels, heavy machinery |
| 62 | 620-820 | ≥500 | ≥16 | High-strength steel structures, special equipment |
Requirements for mechanical properties of weld metal
This standard sets clear requirements for the mechanical properties of weld metal, especially the impact toughness test adopts strict assessment standards:
| Impact requirement level | Test temperature | Number of specimens | Qualification standard | Application scenario |
|---|---|---|---|---|
| Basic requirements | As specified in Table 2 | 5 | Average value ≥27J, single value ≥20J | General working condition welding |
| U-grade requirements | As specified in Table 2 | 3 | Average value ≥ 47J, individual value ≥ 32J | Low-temperature environments, important structures |
The impact test temperature codes cover six temperature levels from -20°C to -60°C, meeting welding requirements under different climatic conditions.
Test Methods and Quality Control
This standard specifies detailed test methods to ensure the accuracy and reliability of test results:
Chemical Composition Analysis: Samples should be taken within a 5mm radius of the weld metal center. Welds within 50mm of the test piece's ends shall not be sampled. The analysis method agreed upon by both the supplier and the buyer shall be used during arbitration testing.
Mechanical properties test: The preparation requirements for gas-electric vertical welding specimens are strict. The welding wire and the test plate plane form an angle of 5°-15°, and the vertical distance between the end of the conductive nozzle and the lower edge of the shielding gas outlet in the slider is controlled at 20-30mm.
| Test items | Test methods | Implementation standards | Qualification standards |
|---|---|---|---|
| Dimensional inspection | Measurement with 0.01mm precision measuring tool | GB/T25775 | Meet tolerance requirements |
| Tensile test | Longitudinal tensile test of weld metal | GB/T2652 | Meet the requirements of Table 1 |
| Impact test | Charpy V-notch impact | GB/T2650-2022 | Complies with 5.3.2 |
| Radiographic Detection | X-ray Film Technology | GB/T3323.1 | Level 1 Acceptance Level |
Implementation Recommendations and Application Guidance
Based on the content of this standard, the following professional suggestions are provided for the implementation of welding projects:
1. Principles of Welding Wire Selection
- Select the matching welding wire tensile strength code according to the strength grade of the base material
- Determine the impact test temperature requirement considering the operating ambient temperature
- Select gas shielded or self-shielded welding wire according to the protection conditions
2. Key points of welding process control
- Strictly control the dry extension length of the welding wire within the range of 25-35mm
- Maintain the shielding gas flow rate at 25-35L/min
- The width of the forming groove of the water-cooled copper slider is 4-8mm larger than the groove width
3. Notes on quality inspection
- Mechanical property specimens should avoid the 50mm area at both ends of the specimen
- The shape and size of the notch of the impact specimen should be inspected under 50x magnification
- X-ray inspection should be completed before cutting the mechanical specimen
During the implementation of this standard, it is recommended that welding practitioners have a deep understanding of the model compilation rules and technical requirements, select appropriate welding wire products according to specific project needs, and strictly follow the test methods specified in the standard for quality inspection to ensure the quality of the welding project.
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