ThePipingMart Blog Grades AISI 309CB Stainless Steel (S30940) – Composition, Properties and Uses

AISI 309CB Stainless Steel (S30940) – Composition, Properties and Uses

309CB Stainless Steel

If you’re in the market for a stainless steel alloy that offers superior corrosion resistance and high-temperature strength, then look no further than 309Cb stainless steel. This alloy is specifically designed to resist oxidation and other forms of corrosion, making it an excellent choice for applications that require high levels of durability. Let’s take a closer look at its composition, physical properties, mechanical properties, and uses.

AISI 309CB Composition

AISI 309Cb (S30940) Stainless Steel is an austenitic chromium-nickel alloy composed of 26% chromium, 20% nickel, 2% molybdenum, and 0.15% carbon. It also contains trace amounts of elements like silicon, phosphorus, sulfur, nitrogen, titanium and aluminium. The addition of these elements helps enhance the properties of the alloy while also improving its weldability.

Element C Mn Si Cr Ni Nb S P
Percent 0.07 1.50 0.50 23.50 13.00 0.80 0.020 0.025

AISI 309CB Physical Properties

Grade 309CB has a melting point range between 2550F – 2635F (1399C – 1446C). Its density is 0.285 lb/in3 (8 g/cm3), and it has a modulus of elasticity in tension (E) of 28 x 106 psi (193 GPa). Its electrical resistivity at 68°F (20°C) is 29 μΩ•in2/m (0.68 μΩ•cm).

AISI 309CB Mechanical Properties

The ultimate tensile strength for this alloy is 80-95 ksi (551-655 MPa), while its yield strength is 40 ksi (~275 MPa). It has an elongation at a break rate between 45-55%. Its hardness ranges from 95 to 110 Rockwell B scale. Therefore, it can withstand high levels of stress without deforming or breaking under strain.

UTS Elongation
(MPa) (L= 5d)%
624 33.0

AISI 309CB Uses

This alloy can be used in many industries due to its excellent mechanical properties and corrosion resistance qualities. It’s frequently used in chemical processing equipment such as tanks and piping systems due to its ability to resist corrosion from harsh chemicals like acids and alkalis. It’s also commonly found in the aerospace industry because it can withstand extremely high temperatures without losing its strength or becoming brittle over time. Other applications include exhaust manifolds on cars and motorcycles as well as heat exchangers in power plants due to their excellent thermal conductivity properties.


309Cb stainless steel provides excellent corrosion resistance and high-temperature strength, making it perfect for use in chemical processing equipment tanks and piping systems as well as aerospace applications where extreme temperatures are common. Thanks to its composition, which includes trace amounts of elements like silicon, phosphorus, sulfur, nitrogen titanium, and aluminium, this stainless steel offers superior performance when compared with other alloys making it suitable for many industries where durability is essential for success, including automotive exhaust manifolds heat exchangers in power plants etc. If your application requires superior performance, then consider using 309cb stainless steel today!

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