Railway Weathering Wire Steel Quality Appraisal

railway weather-resistant welded wire steel is based on the core principle of synergistic corrosion resistance of alloy elements and welding metallurgical stability. By optimizing the proportion of copper, chromium, nickel and other weather-resistant elements and micro-alloying treatment, it achieves the synergy of weld strength, toughness and atmospheric corrosion resistance. It is widely used in fields such as railway bridges, catenary pillars, track welding and outdoor steel structures. In high-speed railway construction, it is used for welding repair of the steel structure of cross-river bridges; in electrified railways, it meets the weather resistance requirements of the catenary support structure; in heavy-haul railway scenarios, it ensures the fatigue resistance of track welded joints. Compared with ordinary welding wire steel, railway weather-resistant welding wire steel has the characteristics of strong resistance to salt spray corrosion, excellent low-temperature impact toughness, and low welding smoke. It is a key material for the long-term and safe operation of railway projects.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide quality appraisal services for railway weather-resistant welding wire steel. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for railway weather-resistant welding wire steel quality appraisal.

As the weather resistance requirements of railway projects have been upgraded, related quality dispute cases have increased significantly. The judicial dispute focuses on:

1. Disputes over performance indicators: whether the salt spray resistance test cycle of the weld meets the standard and whether the -40°C impact energy complies with the technical agreement;

2. Material defects: insufficient weather-resistant element content, welding wire The thickness of the copper plating layer is uneven;

3. Process problems: Insufficient smelting deoxidation leads to porosity >3%, improper wire rod drawing process causes surface micro-cracks;

4. Contract performance disputes: material substitution, welding wire diameter tolerance.

Railway weather-resistant welding wire steel quality identification technical methods mainly include:

1. Chemical composition analysis: Use a spectrometer or other analytical instruments to measure the chemical composition of the welding wire to ensure that it meets the standard requirements.

2. Mechanical performance testing: Test the strength, plasticity and toughness of the welding wire through tensile test, yield strength test, impact test and other methods.

3. Coating quality inspection: Evaluate the integrity, uniformity and thickness of the welding wire coating through microscopic inspection, coating thickness measurement and other methods.

4. Welding performance test: Use a welding simulation testing machine to simulate actual welding conditions and test the welding performance of the welding wire, including welding efficiency, molten pool stability and weld quality.

The applicant, a railway engineering bureau, and the respondent, a welding materials factory, signed the "ER55-Q Weather Resistant Welding Wire Procurement Contract", stipulating that the welds should be salt spray resistant for ≥ 600 hours. After construction, the bridge's welds showed rust and peeling, and the manufacturer argued that it was a defect in the coating process.

Identification and analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of "railway weather-resistant welding wire steel", contract technical agreements, on-site inspection case materials and other data, and made the following quality analysis opinions:

The involved wire had a Cu content of 0.18% (agreement ≥ 0.25%) and a Cr content of 0.45% (agreement ≥ 0.6%); the porosity of the weld was 4.2% (standard ≤ 2%), and red rust appeared in the salt spray test after only 380 hours; the local thickness of the copper-plated layer of the welding wire was only 3 μm (agreement 8-12 μm).

The appraisal conclusion concluded that the manufacturer failed to control the ingredients and coating process according to the agreement, and material defects were the main cause of corrosion failure.

Railway weather-resistant welding wire steel quality appraisal report mainly includes the following contents:

1. Client information

2. Appraisal equipment information

3. Appraisal basis (standard, power of attorney, etc.)

4. Identification method