Military steel wire rope quality appraisal

As the core load-bearing component of military equipment, military steel wire rope is based on the core principle of twisting high-strength steel wire to form a flexible load-bearing structure. It is widely used in aerospace, ships, weapons and other fields. In the spacecraft launch system, it is responsible for the tasks of hoisting the launch vehicle and connecting the escape tower; on the navy ships, it is used in the carrier-based aircraft arresting cable and anchor chain system; in the army equipment, it is used as a key component of the armored vehicle towing and artillery stabilizing device. Compared with civilian steel wire ropes, military products have higher technical requirements.

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

With the modernization and upgrading of military equipment, cases of disputes over the quality of military steel wire ropes have gradually increased. The judicial dispute focuses on:

1, whether the product meets the mechanical performance indicators such as breaking tensile strength and number of twists stipulated in the contract;

2, whether there is any degradation due to steel wire material (such as 60Si2MnA Misuse of ordinary carbon steel), premature fracture caused by defects in the twisting process; whether the surface treatment process is up to standard (such as insufficient thickness of the galvanized layer);

3, and the correlation between quality problems and equipment accidents.

In such cases, the quality appraisal of military steel wire ropes needs to be combined with material composition analysis, mechanical property testing and failure mode analysis to provide a scientific basis for the court to determine the attribution of liability and ensure the quality and safety of national defense equipment.

Military wire rope quality identification technical methods include:

1. Macroscopic inspection: Visual inspection of the appearance, surface defects, diameter and pitch of the wire rope.

2. Tensile test: Place the steel wire rope sample on the tensile machine, apply a certain load to stretch it, and record its breaking load, yield strength, elongation and other indicators.

3. Bending test: Wrap the steel wire rope sample on a bending machine with a specified diameter, bend it a certain number of times, and observe its wire breakage, cracking, etc.

4. Fatigue test: Apply alternating load to the steel wire rope sample and conduct a certain number of fatigue cycles to evaluate its fatigue resistance.

An equipment manufacturing company of the applicant signed a "High Strength Steel Wire Rope Procurement Contract" with a special steel rope company of the respondent, agreeing to purchase 20 6×36WS+IWR steel wire ropes with a nominal diameter of 40mm for use in a certain type of equipment towing system. During use, many wire ropes broke prematurely, causing damage to the equipment. The manufacturing company believed that the wire rope had quality defects and demanded compensation for losses. The steel rope company argued that the breakage was caused by improper use, and both parties went to court.

Identification analysis results:

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

The steel wire material of the military steel wire rope involved in the case is 45 steel (contract requirements) 60Si2MnA), the tensile strength is only 1200MPa (standard ≥2000MPa); the thickness of the galvanized layer is only 50μm (standard ≥85μm), and red rust appears in the salt spray test for 480 hours; insufficient twisting tension causes the steel wire to loosen its strands, and the single-strand wire breakage rate reaches 8% (standard ≤5%).

The steel rope company failed to provide 60Si2MnA steel wire ropes according to the contract, and the galvanizing layer and phosphating process were not up to standard, which was the main reason for the equipment problems.

Military wire rope quality appraisal report should include the following content:

1. The purpose and basis of the appraisal.

2. Model, specification, manufacturer and other information of the equipment being identified.

3. Identification method.

4. Identification results (including whether there are quality problems, causes of problems, etc.).