I. Classification by Material Grade

1. 304 Stainless Steel Pipe: A versatile stainless steel offering excellent corrosion resistance and workability, widely used in food processing, chemical, and medical industries.
2. 316 Stainless Steel Pipe: Enhanced with molybdenum over 304 stainless steel, it offers superior corrosion resistance, particularly suited for marine environments and highly corrosive chemical applications.
3. 321 Stainless Steel Pipe: Incorporates titanium for excellent intergranular corrosion resistance, making it ideal for equipment and piping in high-temperature environments.

II. Classification by Specifications

1. Outer Diameter: Common outer diameter specifications include 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 27mm, 32mm, 38mm, 42mm, 45mm, 48mm, 51mm, 57mm, 60mm, 76mm, 89mm, 108mm, 114mm, 133mm, 159mm, 168mm, 219mm, 273mm, 325mm, 377mm, 426mm, etc.

2. Wall Thickness: Wall thickness specifications vary depending on the outer diameter, typically ranging from 0.5mm to several tens of millimeters. For example, a stainless steel pipe with an outer diameter of 16mm may have wall thicknesses of 1mm, 1.2mm, 1.5mm, and so on.
3. Length: Stainless steel pipes are typically available in fixed lengths and custom lengths. Fixed lengths commonly include 3m, 4m, 6m, etc., while custom lengths are cut according to customer specifications.

Additionally, stainless steel pipes can be categorized into seamless pipes and welded pipes based on manufacturing processes; they can also be classified into decorative pipes, industrial pipes, fluid conveyance pipes, and others according to their applications. Different models and specifications cater to diverse fields and requirements.