Stainless steel tube is a hollow, long, round steel product, primarily widely used in industrial pipelines for oil, chemical, light industry, and mechanical instruments, as well as in mechanical structural components. Additionally, due to its lighter weight while maintaining the same bending and torsional strength, it is also extensively used in the manufacturing of mechanical parts and engineering structures.
Stainless steel pipes can be categorized by composition into Cr series (400 series), Cr-Ni series (300 series), Cr-Mn-Ni series (200 series), and precipitation hardening series (600 series). 200 Series - Chromium-Nickel-Manganese Austenitic Stainless Steel; 300 Series - Chromium-Nickel Austenitic Stainless Steel.
301 - Excellent formability for molding products. Can be rapidly hardened through mechanical processing. Good weldability. Better wear resistance and fatigue strength than 304 stainless steel.
302----- Corrosion resistance similar to 304, with higher carbon content for improved strength.
303 - Added minimal amounts of sulfur and phosphorus make it easier to machine than 304.
304——also known as 18/8 stainless steel. The GB brand number is 0Cr18Ni9. 309—has better temperature resistance compared to 304.
316 - A widely used steel grade after 304, primarily used in industrial and equipment applications. The addition of molybdenum gives it a special corrosion-resistant structure. Due to its superior chloride corrosion resistance compared to 304 stainless steel pipes, it is also used as "shipboard steel." SS316 is typically used in nuclear fuel recovery units. 18/10 grade stainless steel pipes usually meet this application level as well.
Model 321 — Similar to 304 in all other performance aspects, except for the addition of titanium, which reduces the risk of weld seam rust.
400 series – Ferritic and Martensitic stainless steel.
408 - Good heat resistance, slight corrosion resistance, 11% Cr, 8% Ni.
409 — Economy Model (US/UK), commonly used for car exhaust systems, belongs to ferritic stainless steel (chrome steel).
410—Martensitic (high-strength chromium steel), good wear resistance, poor corrosion resistance.
416—Added sulfur to improve the material's processing properties.
420—“Tool Steel” Martensitic stainless steel, similar to early stainless steels like high-chromium Beryllium. Also used for cutting tools, capable of being highly polished.
430—Ferritic stainless steel, decorative, e.g., for automotive accessories. Good formability, but lower temperature resistance and corrosion resistance.
440—High carbon high-strength tool steel, with slightly higher carbon content. Proper heat treatment yields a higher yield strength and hardness up to 58HRC, classifying it among hard stainless steels. Common applications include razor blades. Three common grades are: 440A, 440B, 440C, and also 440F (easy to machine).
500 Series — Heat Resistant Chromium Alloy Steel
600 Series - Martensitic precipitation-hardening stainless steel tubes.