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In modern industrial manufacturing, architectural decoration, household products, and even food processing, 304 stainless steel plates have become one of the most widely used stainless steel materials due to their excellent corrosion resistance, good processability, and high strength. When selecting 304 stainless steel plates, the choice of thickness specifications is crucial, as it not only directly affects the performance and safety of the final product but also relates to cost control and processing efficiency. Therefore, how to accurately match the thickness specifications of 304 stainless steel plates is a core issue that procurement and design personnel must thoroughly understand. I. Understanding the Basic Properties of 304 Stainless Steel Plates Before discussing thickness selection, it is essential to clarify the basic properties of 304 stainless steel. As an austenitic stainless steel, 304 stainless steel mainly consists of 18% chromium and 8% nickel (known as 18-8 stainless steel). It exhibits good oxidation resistance, acid and alkali corrosion resistance, as well as excellent weldability and hot/cold workability. It is widely used in kitchenware, medical equipment, chemical equipment, building curtain walls, elevator panels, food machinery, and other fields. However, even with the same material, plates of different thicknesses vary significantly in mechanical properties, bending strength, pressure resistance, and heat transfer efficiency. Therefore, thickness is not an isolated parameter but a key indicator closely linked to multiple factors such as service environment, load conditions, and processing technology. II. Common Standards and Expression Methods for Thickness Specifications The thickness of 304 stainless steel plates is usually marked in millimeters (mm), with a common thickness range from 0.3mm to 100mm. It can be specifically classified into the following categories: – **Thin plates**: 0.3mm – 3mm, often used in decorative panels, kitchenware, ventilation ducts, and other scenarios with low strength requirements. – **Medium plates**: 3mm – 12mm, widely applied in equipment casings, storage tanks, platform pedals, structural supports, etc. – **Thick plates**: Above 12mm, mainly used in high-strength demand scenarios such as pressure vessels, heavy machinery, ship components, and bridge supports. In addition, there are two ways to express thickness: “nominal thickness” and “actual thickness”. Due to tolerances in the production process, the actual thickness may be slightly lower than the nominal value. For example, a plate labeled 1.0mm may measure 0.97mm in actuality. Therefore, in high-precision applications, it is necessary to clearly specify the tolerance grade (e.g., Grade A or Grade B tolerance in the GB/T 709 standard) to avoid structural failure caused by insufficient thickness. III. Core Factors for Accurately Matching Thickness 1. Service Environment and Load Requirements This is the primary factor determining thickness. For instance, in outdoor building curtain walls, plates need to withstand wind pressure, rain and snow loads, and temperature changes, so a thickness of 1.5mm – 3.0mm is usually selected to ensure structural stability. In contrast, for indoor decoration, 0.5mm – 1.2mm is sufficient to meet visual and light-load needs. For load-bearing structures like work platforms or stair treads, mechanical calculations are required. Based on the span, support method, and expected load, the required section modulus is estimated using the bending stress formula (σ = M/W), and then the minimum thickness is derived. For example, a platform with a 2-meter span typically requires a medium plate of 4mm or more if it needs to bear a load of 200kg/m². 2. Processing Technology and Forming Requirements Different processing methods have specific requirements for thickness. Examples include: – **Bending processing**: Thin plates (<2mm) are easy to bend, but excessively thick plates require large-tonnage bending machines and are prone to springback. Generally, it is recommended that the bending radius be no less than 1.5 times the material thickness. - **Stamping forming**: Thin plates are more suitable for complex stamping parts, such as stainless steel sinks, with a common thickness range of 0.8mm – 1.2mm. - **Welded structures**: Welding of thick plates requires preheating and interlayer control to prevent cracks, while thin plates are prone to burn-through and require precise control of heat input. 3. Balance Between Cost and Economy Thickness directly determines material costs. Since 304 stainless steel is relatively expensive, blindly choosing excessively thick plates leads to resource waste. For example, the original design thickness of a certain equipment casing was 3mm; after optimization through finite element analysis, it was changed to 2mm, which still meets the strength requirements while reducing material costs by approximately 30%. Therefore, simulation analysis and actual testing should be combined to achieve a "just sufficient" thickness design. 4. Surface Treatment and Aesthetic Requirements In decorative applications, thickness affects the flatness and dent resistance of the plate. Thin plates are easily deformed by external forces, affecting appearance; while appropriate thickening can enhance texture. For example, elevator car panels often use 1.5mm – 2.0mm thickness, which not only ensures rigidity but also facilitates wire drawing or mirror finishing. 5. Industry Standards and Regulatory Requirements Certain industries have clear thickness regulations. For example, food machinery must comply with the GB 4806.9 standard, which requires smooth contact surfaces without dead corners, so plates with a thickness of 1.0mm or more are usually selected for easy cleaning. Pressure vessels, on the other hand, must follow the GB 150 standard, where the minimum thickness is calculated based on the design pressure, temperature, and medium, with consideration of corrosion allowance. IV. Practical Selection Suggestions and Processes 1. Clarify the application and working conditions: List the service environment, load type, temperature range, corrosive medium, etc. 2. Preliminary thickness estimation: Conduct a rough calculation by referring to similar cases or using engineering handbooks. 3. Conduct structural analysis: Use CAD/CAE software for stress simulation to verify the rationality of the thickness. 4. Consider processing feasibility: Communicate with the manufacturing department to confirm the thickness limitations for processes such as bending, cutting, and welding. 5. Compare cost and service life: Evaluate the total cost (material + processing + maintenance) under different thicknesses and select the solution with the best cost-effectiveness. 6. Request sample testing: For critical applications, ask suppliers to provide samples for actual assembly or performance testing. In summary, when selecting 304 stainless steel plates, thickness selection is by no means simply "the thicker the better" or "the thinner the more cost-saving". It is a systematic project that requires comprehensive consideration of multiple factors, including material properties, mechanical requirements, processing technology, cost control, and industry standards. Only through scientific analysis and accurate matching can the optimal use of materials be achieved while ensuring safety and functionality. It is recommended to fully communicate with professional engineers or the technical team of suppliers before procurement to obtain customized suggestions and avoid quality problems or resource waste caused by improper thickness.