I. Raw Material Procurement and Inspection
Raw materials are the bedrock of steel structure product quality. They mainly consist of steel (such as H - beams, channel steels, steel plates, etc.) and various accessories (bolts, connectors, etc.). These are sourced from well - known domestic steel mills and regular accessory suppliers to ensure consistent quality.
Upon arrival at the factory, raw materials are meticulously inspected following national standards. This inspection covers material testing, dimension verification, and other aspects. A detailed inspection report is generated for each batch.
II. Cutting
Cutting is the initial step in the production process. In line with the order drawings, raw materials are cut into the required sizes and shapes. The factory predominantly uses two cutting methods: laser cutting, which is applied to plate cutting and section - steel cutting, and flame cutting.
Laser cutting is characterized by high speed and precision. It is well - suited for thin steel materials with a thickness of ≤ 20mm. Post - cutting, the surface is flat, facilitating subsequent processing. Flame cutting, conversely, is appropriate for thick steel materials with a thickness > 20mm, such as large steel beams and columns. However, it has a slower cutting speed and slightly lower precision. Cutting complex and irregularly - shaped components may take longer.
III. Processing and Shaping
This is the core stage of steel structure production, involving processes like assembly welding, drilling, and bending.
Assembly
Positioning, leveling, and alignment are executed strictly according to the drawing dimensions. Deviations in the straightness, perpendicularity, gaps, and misalignment of components are closely monitored. It is essential to ensure components fit snugly, gaps are uniform, and positioning is accurate. Forced assembly and misaligned assembly are strictly prohibited, as assembly precision dictates overall component dimensions, welding deformation, and the subsequent installation qualification rate.
Welding
Two welding techniques, full welding and segment welding, are employed. The choice of technique depends on the stress requirements of the components. Welding operators are professionally trained to ensure that welding quality adheres to national standards, free from slag inclusions, pores, cracks, etc., with a smooth and flat appearance.
Bending
Cut steel pieces are bent into desired shapes such as U - shaped grooves and L - shapes as per the drawing specifications. Specialized bending equipment is utilized to ensure that the bending angle error remains within the allowable range. The precision of bending significantly impacts the subsequent assembly fit.
Drilling
Holes are drilled in the components according to assembly requirements. The accuracy of hole diameter and hole position must strictly follow the drawings to prevent any adverse effects on subsequent assembly.
IV. Surface Treatment
Surface treatment is of great significance for the service life of steel structure products, particularly in outdoor, coastal, or highly corrosive environments. The treatment mainly involves rust removal and subsequent painting or galvanizing.
Rust Removal
Two methods, shot blasting and sandblasting, are commonly used. Shot blasting is highly efficient and effective in thoroughly removing rust and scale from the steel surface, making it suitable for batch processing. Sandblasting, on the other hand, is more precise and is ideal for decorative steel structures with high surface finish requirements.
Painting / Galvanizing
After rust removal, the choice between painting and galvanizing is made based on customer needs. Painting is cost - effective and offers a wide range of color options, making it suitable for indoor or outdoor projects with general anti - corrosion requirements. Galvanizing, on the contrary, provides excellent corrosion resistance and a longer service life, making it suitable for outdoor, coastal, or highly corrosive environment projects.
V. Assembly and Inspection
This is the final quality - control phase before product dispatch. Components and parts that have undergone processing and surface treatment are assembled in accordance with the order drawings. The assembly precision is then inspected to ensure it meets the design requirements.
Post - assembly, dimension re - verification (checking key parameters such as component length, width, and angle) and quality inspection (including re - inspection of welding quality and surface treatment effect) are carried out. All inspections are conducted in line with international standards, and a detailed inspection report is issued for qualified products.
VI. Packaging and Out - of - stock
Shipping orders have stringent packaging requirements. Adhering to the principles of waterproofing, moisture - proofing, and rust - prevention, three types of packaging are used based on product type and transportation method:
Nude Packing
Suitable for large components like large steel beams and columns, only rust - proof oil is applied to the component surface. This method is suitable for sea or land transportation and has the lowest cost.
Packaging Film Wrapping
Ideal for small and medium - sized components, they are tightly wrapped with waterproof packaging film to prevent moisture and rust. The cost of this method is moderate.
Wooden Box Packaging
This is suitable for small accessories, precision components, or customers with high packaging demands. The wooden box is made of waterproof and moisture - proof materials to safeguard the product from collision - induced damage, though it comes at a relatively higher cost.
