Widely used in petroleum,foodstuff,chemical industry,construction, electric power,nuclear,energy,machinery,biotechnology,paper
making,shipbuilding,boiler fields.
Pipes also can be made according to the customer's required.
Structural & Dimensional Advantages of 40x40mm Square Cross-Section
The fixed 40x40mm size is a "universal medium specification" for square pipes, with unique advantages in load-bearing, installation, and space utilization:
1. Optimized Load-Bearing for Medium-Duty Scenarios
The 40x40mm square cross-section has a uniform moment of inertia (higher than round pipes of the same outer diameter, e.g., φ40mm round pipe) and a flat stress surface. When used as a support (e.g., handrails, equipment frames), it can bear 15-20% more static load (e.g., 304 grade 40x40 pipe with 2mm wall thickness can bear ~500kg vertical load) than smaller square pipes (e.g., 30x30mm).
The square shape avoids rolling during installation, making it easier to fix with brackets or bolts—critical for applications like workshop shelves or exhibition stands.
2. Versatile Installation & Compatibility
Standardized Size: 40x40mm is a widely used specification in the industry, so it matches most standard stainless steel accessories (e.g., 40x40 corner brackets, square pipe connectors, end caps). No need for custom adapters, reducing installation time and cost.
Space-Saving Assembly: Flat sides enable tight right-angle connections or parallel splicing (e.g., forming a grid structure for partitions). Compared to round pipes, it reduces gaps between components by 30-40%, optimizing space in compact areas (e.g., small workshops, kitchen backyards).
Factories usually produce 40x40 square pipes with wall thicknesses of 1.0mm (light-duty), 1.5-2.0mm (medium-duty), and 2.5-3.0mm (heavy-duty), matching different load needs:
1.0mm: Suitable for decorative applications (e.g., indoor handrails, display racks) where weight is a priority.
1.5-2.0mm: Ideal for general industrial use (e.g., workshop equipment frames, conveyor supports) balancing weight and strength.
2.5-3.0mm: Used for heavy-duty scenarios (e.g., outdoor billboard frames, mechanical load-bearing parts) requiring high durability.
Merits of Welding Process
All 40x40 square pipes are manufactured via welded forming (common methods: TIG welding, laser welding), which brings unique advantages compared to seamless pipes:
1. Cost-Effectiveness & High Production Efficiency
Welded pipes are made by rolling stainless steel coils/sheets into a square shape and then welding the seam. The process is mature and suitable for mass production, so the cost of 40x40 welded square pipes is 20-30% lower than seamless ones—critical for large-volume procurement (e.g., construction projects, workshop renovations).
2. Stable Weld Quality (Factory-Standard Control)
Reputable manufacturers conduct strict quality checks on welds:
Non-Destructive Testing (NDT): Ultrasonic testing or X-ray inspection to eliminate defects like pores, cracks, or incomplete fusion.
Post-Weld Treatments: Annealing (to reduce internal stress) and passivation (to enhance weld corrosion resistance) ensure the weld strength and corrosion resistance are close to the base material. For 304/316 grades, the weld area can even pass salt spray tests (304: 48 hours no rust; 316: 100 hours no rust).
3. Consistent Dimensional Accuracy
Welding processes (especially laser welding) enable precise control of the 40x40mm cross-section (tolerance ≤ ±0.5mm) and wall thickness (tolerance ≤ ±0.1mm). This ensures uniformity when multiple pipes are assembled—avoiding gaps or misalignment in scenarios like grid partitions or frame structures.
