（1）Stainless steel plate

Chromium reacts with oxygen to form a dense chromium oxide passivation film, which prevents the internal metal from being corroded and has strong resistance to acids, alkalis, salts and humid environments. For instance, 304 stainless steel hardly rusts in humid air, while 316 stainless steel is resistant to seawater corrosion.

（2）Carbon steel plate

Lacking the protection of a passivation film, it is prone to rust (Fe₂O₃ · nH₂O) in damp, acidic or alkaline environments. Rust prevention is required through surface treatments such as painting and galvanizing.

2. Strength and toughness

（1）Stainless steel plate

Austenitic stainless steel (such as 304) : High toughness, medium strength, non-magnetic, suitable for stretching and stamping processing.

Martensitic stainless steel (such as 410) : It can be strengthened by heat treatment, with high strength (similar to carbon steel), but lower toughness.

（2）Carbon steel plate

Low-carbon steel (C≤0.25%, such as Q235) : Good toughness, low strength, and easy to process.

High carbon steel (C≥0.6%, such as T10) : It has high strength and hardness, but is brittle and prone to fracture.

3. Processing and welding performance

（1）Stainless steel plate

High processing difficulty: It has great toughness and is prone to sticking to the cutting tool during cutting, so special tools (such as ceramic tools) are required.

Welding requires special electrodes (for example, 308L corresponds to 304 stainless steel), and the temperature needs to be controlled to avoid intergranular corrosion.

（2）Carbon steel plate

Good processing performance: It can be easily cut, welded and forged, and can be processed with ordinary tools.

The welding is simple. Common electrodes (such as J422) can meet the requirements, and the process requirements are low.

4. Cost and Density

（1）Stainless steel plate

The cost is high (alloying elements such as chromium and nickel are expensive), and the density is approximately 7.93g/cm³ (such as 304).

（2）Carbon steel plate

Low cost (cheap raw materials), with a density of approximately 7.85g/cm³, offering high cost performance.

5. Appearance and Magnetism

（1）Stainless steel plate

The surface is bright and can be polished or brushed. Austenitic stainless steel (such as 304) is non-magnetic, while martensitic/ferritic stainless steel is magnetic.

（2）Carbon steel plate

The surface is dark grey, prone to oxidation and rust, and generally requires painting. All of them are magnetic.

6. Comparison of application scenarios

Application scenarios of stainless steel plates

Corrosion-resistant environments: chemical equipment, seawater engineering, food processing (such as storage tanks, pipelines), medical devices (to prevent bacterial growth).

Aesthetic and hygiene requirements: Kitchen utensils, architectural decoration (curtain walls, railings), bathroom facilities.

High-temperature environment: Boilers, heat exchangers (some stainless steels such as 310S have a temperature resistance of ≥1000℃).

Scenarios where carbon steel plates are applicable

Structural support and load-bearing: building frames, Bridges, mechanical bases (such as Q345B low alloy high strength steel).

Common mechanical parts: gears, shafts, bolts (surface rust prevention treatment required).

Low-cost demand scenarios: ordinary pipes, brackets, car bodies (galvanized carbon steel for rust prevention).