The processing technology of stainless steel products involves multiple stages, and the choice of each technology depends on the product's application, shape requirements, and performance needs. Here is a comprehensive analysis:

I. Selection of Stainless Steel Materials

Common Types
Austenitic (304, 316): Corrosion-resistant and non-magnetic, suitable for food and medical applications.
Martensitic (410, 420): Can be strengthened by heat treatment, used for cutting tools and mechanical parts.
Ferritic (430): Magnetic, oxidation-resistant, low cost, used for household appliances and decoration.
Duplex Steel (2205): High strength + corrosion resistance, used for chemical and marine environments.
Selection Criteria
Corrosion resistance, strength, processability, and cost.

II. Main Processing Technologies

1. Cutting and Material Preparation

Laser Cutting: High precision, suitable for complex shapes, thickness usually ≤20mm.
Plasma Cutting: Suitable for thick plates (≤50mm), low cost but slightly lower precision.
Water Jet Cutting: No thermal deformation, can cut ultra-thick plates (≤100mm), but slow speed.
Shearing Machine: Simple linear cutting, high efficiency, only for thin plates.

2. Forming Processing

Bending: Using a bending machine, need to pay attention to the minimum bending radius (e.g., radius of 304 stainless steel ≥ plate thickness).
Stamping: Suitable for mass production of shells and hardware parts, need to prevent cracking (e.g., use deep-drawing 304 material).
Spinning: Used for axially symmetric parts (e.g., stainless steel cups, lamp shades).
Rolling: Processing pipes and cylinders through a plate rolling machine.

3. Welding Processes

TIG Welding (Tungsten Inert Gas Welding): High-quality welds, suitable for thin plates (0.5~6mm).
MIG Welding: High efficiency, suitable for medium-thick plates, need to use stainless steel-specific welding wire (e.g., ER308).
Resistance Welding: Spot welding, seam welding, used for thin plate lap joints (e.g., water tanks).
Laser Welding: Precision welding, small heat-affected zone, but high equipment cost.

4. Surface Treatment

Mechanical Polishing: Divided into rough polishing and fine polishing, can achieve a mirror finish (Ra≤0.1μm).
Electrolytic Polishing: Removing burrs, improving corrosion resistance, suitable for complex parts.
Sandblasting/Brushing: Matte texture (commonly with 180~240 grit sand particles).
PVD Coating: Adding color (e.g., rose gold, black titanium) and wear resistance.
Passivation Treatment: Soaking in nitric acid or citric acid to enhance corrosion resistance (removing iron impurities).

5. Heat Treatment

Solution Treatment (Austenitic Steel): Fast cooling at 1050~1100℃ to eliminate processing stress.
Quenching and Tempering (Martensitic Steel): Increase hardness (e.g., 440C quenched HRC≥55).
Stress Relief Annealing: Slow cooling at 300~400℃ to prevent deformation.

III. Key Points to Note

Deformation Control
Use fixtures during processing to avoid heat concentration (e.g., segmented welding).
Symmetrical processing (e.g., symmetrical cutting or bending).
Corrosion Resistance Protection
Avoid carbon steel contamination (use dedicated tools and workbenches).
Welding should be followed by acid washing and passivation (especially for 316L welds).
Cutting Tools and Parameters
Turning/Milling: Use cemented carbide or coated tools, low speed with large feed.
Drilling: Use high-cobalt drill bits (e.g., M35), add cutting fluid to cool down.

IV. Typical Application Process Examples

Stainless Steel Sink
304 sheet metal → Laser cutting → Hydraulic stretching forming → Welding corners → Polishing → Electrolytic passivation.
Medical Instruments (Surgical Forceps)
420 Martensitic Steel → Precision stamping → Heat treatment (quenching + low-temperature tempering) → Electrolytic polishing → Sterilization and packaging.
Decorative Tubing
201/304 Tubing → Forming by bending machine → Welding → PVD titanium gold plating → Quality inspection.

V. Common Issues and Solutions

Scratches: Cover with protective film or switch to nylon fixtures.
Weld Rust: Check the compatibility of welding materials (e.g., use ER316L welding wire for 316L).
Cracking: Preheat martensitic steel before welding (150~200℃).
By reasonably selecting process combinations and parameters, the aesthetics, functionality, and cost of stainless steel products can be balanced. In actual production, the process chain needs to be adjusted based on sample testing.