What are the requirements for materials for customized processing of sheet metal cabinets?

The customized processing of sheet metal cabinets requires strict materials, and it is necessary to comprehensively consider the use environment, functional requirements, structural strength and cost of the cabinets. The following details the requirements to be met by materials from multiple dimensions:

A, mechanical properties requirements

Sheet metal cabinets need to bear their own weight, the weight of internal equipment and possible external impact and vibration, so the mechanical properties of materials are the basis:

Strength: Sufficient tensile strength and yield strength are required to ensure that the cabinet will not deform or collapse when carrying equipment (such as servers and switches). Common materials such as cold-rolled steel plate (tensile strength 375-500MPa) and hot-rolled steel plate (tensile strength 370-500MPa) can meet most load-bearing requirements.

Stiffness: the elastic modulus of materials should be moderate to ensure the stability of the cabinet structure, and it is not easy to bend or twist due to external forces (such as handling and installation). For example, the elastic modulus of steel plate is about 200GPa, which is much higher than that of aluminum alloy (69GPa), so it is suitable for scenes with high rigidity requirements.

Toughness: under low temperature or impact environment (such as outdoor cabinet), the material should have certain toughness to avoid brittle fracture. Low carbon steel (carbon content ≤0.25%) has good toughness, while high carbon steel is easy to embrittle and is rarely used for cabinet processing.

Second, the corrosion resistance requirements

Cabinets are often exposed to different environments (such as indoor humid environment, outdoor wind and rain, industrial dust), and the corrosion resistance of materials directly affects the service life:

Adaptability to natural environment: ordinary cold-rolled steel plates can be used for indoor cabinets (which need to be painted for rust prevention); Outdoor cabinets shall be resistant to ultraviolet rays and rain, and galvanized steel plates (with zinc layer thickness ≥ 80g/m) and stainless steel (such as 304 stainless steel, which contains 18% chromium and 8% nickel and has strong acid and alkali resistance) shall be preferred.

Special requirements of industrial environment: In high salt fog environment such as chemical industry and coastal areas, it is necessary to adopt 316 stainless steel (containing 2-3% molybdenum, and its chloride ion corrosion resistance is better than 304), or carry out phosphating+plastic spraying treatment on the steel plate (coating thickness ≥60μm).

Third, the processing technology adaptability requirements

Sheet metal processing involves cutting, bending, welding, stamping and other processes, and the materials should have good processability:

Cutability: steel plate with thickness ≤10mm is suitable for laser cutting (smooth incision); Hot-rolled steel plate with thickness > ＞10mm needs plasma cutting, which requires less material impurities (such as sulfur content ≤0.045%) to avoid cracks during cutting.

Flexibility: the material should be sufficiently plastic and not easy to crack when bending. For example, the elongation of cold-rolled steel plate is ≥20%, which is suitable for complex bending forming (such as corner and column bending of cabinet); However, high-hardness steel plates (such as spring steel) are not suitable for cabinet processing because of their poor plasticity and easy to break when bending.

Weldability: ensure that the weld is firm and free of air holes when welding. Low carbon steel (carbon content ≤0.25%) has the best weldability, stainless steel needs argon arc welding to avoid oxidation, and aluminum alloy needs special aluminum welding wire and welding process (such as MIG welding).

Punchability: When used to punch cooling holes and mounting holes, the material should have good ductility to avoid burr or deformation during stamping. The zinc layer of galvanized steel plate should be firmly combined with the substrate to prevent the zinc layer from falling off during stamping.

Four, appearance and surface treatment compatibility requirements

The appearance quality of the cabinet affects the overall aesthetics of the equipment, and the materials should be convenient for subsequent surface treatment:

Surface flatness: the surface roughness Ra of cold-rolled steel plate is less than 1.6 μ m, which is suitable for painting and plastic spraying (uniform coating adhesion); The surface of hot rolled steel plate is rough (Ra≤6.3μm), so it needs to be polished before treatment, otherwise coating bubbles will easily appear.

Adhesion of coating: the surface of the material should be clean and free of oil stains, and the zinc layer of galvanized sheet should be chromated (passivated) to enhance the adhesion with paint.

V. Functional special requirements

According to the specific functions of the cabinet (such as heat dissipation and electromagnetic shielding), the materials shall meet the additional requirements:

Heat dissipation: When used in scenes with high heat dissipation requirements such as server cabinets, aluminum alloy (thermal conductivity is 202 w/(MK), which is much higher than that of steel (45 w/(MK)), but it needs to be matched with reinforcing ribs to make up for the lack of rigidity.

Electromagnetic shielding: In communication, medical treatment and other scenes where electromagnetic interference needs to be prevented, the material should have conductivity, and steel plate (conductivity is about 5.96× 10s/m) should be preferred, and the gap should be sealed by welding (to avoid electromagnetic wave leakage), or electromagnetic shielding coating (such as copper-nickel alloy coating) should be adopted.

Six, cost and economic requirements

On the premise of satisfying the performance, it is necessary to balance the material cost:

Cost-effective selection: cold-rolled steel plate (about 4000-6000 yuan/ton) is preferred for ordinary indoor cabinets, and the cost-effective ratio is higher than that of stainless steel (about 18000-22000 yuan/ton for 304 stainless steel); For temporary cabinets with low rust prevention requirements, hot-rolled steel plates can be selected (the price is 10-15% lower than that of cold rolling).

Material utilization rate: the plate size should be adapted to the processing equipment (for example, the standard plate width is 1220mm and 2440mm), so as to reduce cutting waste and cost.

summary

The selection of customized materials for sheet metal cabinets should be "as needed": cold-rolled steel plates and painting can be selected at room temperature; Outdoor or humid environment is preferred with galvanized sheet or 304 stainless steel; 316 stainless steel for highly corrosive environment; Lightweight or heat dissipation needs to consider aluminum alloy. At the same time, it is necessary to give consideration to processing performance and cost to ensure that the cabinet not only meets the functional requirements, but also has economy.