Quality Control

Quality Control

China Loong Container Co., Ltd. applies structured quality control throughout material sourcing, fabrication, assembly, finishing, and shipment preparation. Our inspection procedures are adapted to the specifications of each order, including ISO shipping containers, dry van containers, high cube containers, flat rack and open top containers, storage containers, reefer containers, energy storage containers, and customized container buildings. The objective is to deliver consistent workmanship, reliable operation, and products that meet agreed technical and commercial requirements.

1. Incoming Material Inspection

Steel components, flooring materials, coatings, seals, locking hardware, insulation materials, and other purchased parts are checked before they enter production. Our inspectors compare incoming materials with approved drawings, purchase requirements, and internal inspection standards.

• Material verification: Material type, thickness, dimensions, surface condition, and supporting documentation are reviewed as applicable.
• Component inspection: Door gear, corner fittings, hinges, gaskets, fasteners, and other functional parts are checked for specification and visible defects.
• Specialized materials: Insulation systems, refrigeration-related components, electrical parts, and tank-related components are evaluated according to the relevant product configuration and order requirements.
• Nonconforming material control: Materials that do not meet the defined requirements are identified and separated for review, replacement, or corrective action.

2. In-Process Quality Control

Quality checks are performed at key production stages rather than relying only on final inspection. Production teams work from confirmed drawings and process instructions, while inspection personnel monitor critical dimensions, fabrication quality, assembly accuracy, and surface preparation.

• Cutting and forming: Panels, frames, rails, posts, and structural parts are checked for dimensions, alignment, and forming quality.
• Welding control: Weld location, continuity, appearance, and workmanship are inspected according to internal requirements and the intended application of the container.
• Frame and body assembly: Squareness, alignment, openings, connection points, and overall dimensions are reviewed during assembly.
• Surface preparation and coating: Cleaning, preparation, primer, topcoat application, color, coverage, and visible finish are checked subject to the specified coating system.
• Customized installations: Doors, windows, insulation, interior panels, ventilation, electrical systems, plumbing, and equipment mounting are inspected when included in container homes, container houses, portable units, or energy storage enclosures.

3. Finished Product Inspection

Each completed product is inspected against the approved order information before release. The inspection scope depends on the container type, intended use, and customer specification. Standard cargo and storage units are assessed differently from reefer containers, tank containers, energy storage containers, or highly customized structures.

• Dimensions and structure: Key dimensions, frame condition, panel alignment, floor installation, corner areas, and structural workmanship are reviewed.
• Door operation: Doors, hinges, locking rods, handles, retainers, and seals are checked for correct installation and smooth operation.
• Appearance: Surfaces are examined for visible dents, sharp edges, coating defects, contamination, and incomplete finishing.
• Weather protection: Seams, roof areas, door seals, and relevant openings may be checked for water resistance or sealing performance where required by the product specification.
• Functional systems: Refrigeration, ventilation, electrical, lighting, plumbing, insulation, access, and safety-related features are checked when they form part of the agreed supply scope.
• Markings and accessories: Identification plates, operating labels, warning labels, loose accessories, and optional equipment are verified against the order requirements.

4. Packaging and Pre-Shipment Check

Before dispatch, China Loong Container Co., Ltd. performs a final review to confirm that the products, quantities, accessories, markings, and shipment details correspond with the order. Because many containers are shipped as complete units, protection focuses on vulnerable surfaces, openings, fittings, equipment, and loose components.

• Interior and exterior areas are checked for cleanliness and foreign materials.
• Doors, windows, vents, hatches, and access panels are secured for transportation.
• Loose parts, documents, and accessories are counted, identified, and packed as appropriate.
• Finished surfaces and exposed components receive suitable protection based on the shipping method.
• Loading arrangements and securing points are reviewed to reduce the risk of movement or handling damage during transport.
• Pre-shipment inspection records and relevant product documents are prepared subject to the agreed order scope.

5. Feedback, Corrective Action, and Continuous Improvement

Quality management continues after shipment. Customer feedback is communicated to the relevant production, engineering, purchasing, and inspection teams for review. When an issue is reported, we assess the available order information, drawings, inspection records, photographs, and application conditions to identify the cause and determine an appropriate response.

Corrective actions may include process adjustment, additional inspection points, supplier review, drawing clarification, work instruction updates, or improved component protection. Findings from completed orders are used to strengthen future production control and support more consistent results across standard and customized container projects.