Zinc steel guardrail quality appraisal

zinc steel guardrail is based on the core principle of metallurgical combination of hot-dip galvanized layer and base material. By optimizing the zinc liquid composition, coating thickness and surface passivation process, it achieves the synergy of high corrosion resistance and structural strength. It is widely used in outdoor protection fields such as municipal projects, residential areas, and industrial parks. In construction projects, it is used for safety enclosures such as balconies and stairs; in the transportation field, it meets the weather resistance requirements of road isolation fences; in industrial scenes, it ensures anti-collision protection in equipment areas. Compared with traditional guardrails, zinc steel guardrails have the characteristics of uniform coating, strong adhesion, and excellent salt spray resistance. They are the key material for long-term anti-corrosion in modern outdoor protection projects.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide zinc steel guardrail quality appraisal services. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for zinc steel guardrail quality appraisal.

With the large-scale application of zinc steel guardrails, related quality dispute cases are increasing year by year. The judicial dispute focuses on:

1. Dispute over performance indicators: whether the actual thickness of the galvanized layer meets the standard and whether the impact strength meets the design value;

2. Material defects: the carbon content of the base material exceeds the standard and the aluminum element content in the zinc liquid is insufficient (resulting in

3, process problems: pickling residue caused blistering of the coating, and uneven thickness of the passivation film caused local corrosion;

4, contract performance dispute: the cross-sectional size of the delivered guardrail and the anti-corrosion process of the connectors were inconsistent with the technical agreement.

According to the "Technical Specifications for Zinc Steel Guardrails" (JC 327-2014):

1. Appearance inspection: Check whether there are scratches, dents, cracks and other defects on the surface of the guardrail.

2. Dimensional measurement: Measure the length, height, width and other dimensions of the guardrail and compare with relevant standards.

3. Material analysis: Use metallographic analysis, spectral analysis and other methods to identify the composition and organizational structure of guardrail materials.

4. Strength test: Evaluate the flexural strength, tensile strength and other properties of the guardrail through bending tests, tensile tests, etc.

A real estate company of the applicant signed a "Zinc Steel Guardrail Purchase Contract" with a guardrail manufacturer of the respondent, and it was agreed that the coating thickness should be ≥80 μm. Half a year after it was delivered for use, the guardrails of the community showed extensive rust, with a corrosion rate exceeding 40%. The real estate company alleged that the galvanizing process was not up to standard, and the manufacturer argued that it was caused by acid fertilizer pollution in the green belt.

identification analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of "zinc steel guardrail", contract technical agreement, on-site investigation case materials and other data, and made the following quality analysis opinions:

The average coating thickness of the guardrail columns involved in the case is only 65μm, and the missed plating area accounts for 12%; the carbon content of the base material is 0.25% (standard Q235B requirement ≤0.20%), resulting in an increase in the brittleness of the welding joint; the chromium content of the passivation film is only 12mg/m² (standard ≥20mg/m²), and the corrosion resistance is reduced.

The appraisal conclusion concluded that the manufacturer failed to control the coating thickness and base material composition in accordance with the agreement, and that process defects were the main cause of rust.

zinc steel guardrail 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