Stainless steel tubes are hollow, long, round steel bars, primarily widely used in industrial pipelines for oil, chemical, light industry, and mechanical instruments, as well as for mechanical structural components. Additionally, with equal bending and torsional strength, they are lighter in weight, making them extensively used in the manufacturing of mechanical parts and engineering structures.
Stainless steel tubes 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 better strength.
303-----Add a small amount of sulfur and phosphorus to make it easier to machine compared to 304.
304 - Also known as 18/8 stainless steel. The GB grade is 0Cr18Ni9. 309 - Offers better temperature resistance compared to 304.
316 - A widely used steel grade following 304, primarily for 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 commonly 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 that it has reduced the risk of weld seam corrosion due to the addition of titanium elements.
400 Series – Ferritic and Martensitic Stainless Steel.
408 - Good heat resistance, mild corrosion resistance, 11% Cr, 8% Ni.
409 — Affordable model (UK and US), commonly used for car exhausts, belongs to ferritic stainless steel (chromium steel).
410—Martensitic (high-strength chrome steel), good wear resistance, poor corrosion resistance.
416—Added sulfur to improve the material's workability.
420—"Tool Steel" Martensitic steel, similar to early stainless steels like high-chromium B AISI steel. Also used for knives, which can be polished to a very shiny finish.
430—Ferritic stainless steel, decorative, such as for automotive accessories. Good formability, but poor temperature resistance and corrosion resistance.
440—High-strength tool steel with slightly higher carbon content. After proper heat treatment, it achieves a high yield strength and hardness up to 58HRC, placing it among the hard stainless steels. Common applications include razor blades. There are three common types: 440A, 440B, and 440C, with 440F (easier to machine) also available.
500 Series - Heat Resistant Chromium Alloy Steel
600 Series - Martensitic precipitation-hardening stainless steel tubes.