Stainless Steel

Stainless Steel Grades and Properties

Stainless Steel grades are divided into 3 different groups according to the specific grade's micro structure, namely Austenitic, Ferritic and Duplex. The amount of each alloying element in the content of a stainless steel grade determines the micro structure.

Austenitic

The austenitic grade has various advantages, including:

  • Excellent corrosion resistance
  • Resistance against high temperature oxidation resistance.
  • Good strength
  • Excellent weldability
  • Excellent formability

The chemical composition consists of low carbon content, but include chromium and nickel.

Chemical Composition

Class Type C Si Mn P S N Cr Mo Nb Ni
Cr-Ni-Mn U-202 0.08 0.75 6.5 - 8.0 0.045 0.015 0.15 15.0 - 17.0 3.5 - 5.0
Cr-Ni U-301LN 0.03 1.0 2.0 0.045 0.015 0.07 - 0.20 16.5 - 18.0 6.0 - 8.0
U-304 0.07 0.75 2.0 0.045 0.015 0.10 18.0 - 19.5 8.0 - 10.5
U-304L ASTM 0.03 0.75 2.0 0.045 0.015 0.10 17.5 - 19.5 8.0 - 10.5
Cr-Ni-Mo U-316L-1.4404 0.03 0.75 2.0 0.045 0.015 0.10 16.5 - 18.0 2.0 - 2.5 10.0 - 13.0
U-316LN 0.03 0.75 2.0 0.045 0.015 0.12 - 0.16 16.5 - 18.0 2.0 - 2.5 8.0 - 10.5
Heat Resistance U-309S-1.4833 0.08 0.75 2.0 0.045 0.015 0.11 22.0 - 24.0 - 18.0 12.0 - 14.0
U-310S-1.4845 0.08 0.75 2.0 0.045 0.015 0.15 0.11 24.0 - 26.0 19.0 - 22.0

Mechanical Properties (Hot Rolled)

Class Type Tensile Strength(MPa) 0.2 Proof Stress (MPa) Elongation (% in 50mm) General Corrosion Properties Pitting Corrosion Properties Formability Properties Toughness Welding Properties
Cr-Ni-Mn U-202 515 205 40 Moderate Moderate Excellent Excellent Excellent
Cr-Ni U-301LN 630 - 830 330 45 Good Good Excellent Excellent Excellent
U-304 520 - 720 250 45 Good Good Excellent Excellent Excellent
U-304L-ASTM 500 - 700 200 45 Good Good Excellent Excellent Excellent
Cr-Ni-Mo U-316L-1.4404 520 - 680 220 45 Very Good Very Good Excellent Excellent Excellent
U-316LN 580 - 780 280 40 Very Good Very Good Excellent Excellent Excellent
Heat Resistance U-309S-1.4833 515 - 700 210 40 Very Good Oxidation Resistance Very Good Oxidation Resistance Very Good Very Good Good
U-310S-1.4845 515 - 700 210 40 Very Good Oxidation Resistance Very Good Oxidation Resistance Very Good Very Good Good

Ferritic

The following advantages and characteristics will be found in the ferritic grade:

  • The ferritic grae is magnetic
  • Good strength
  • The corrosion resistance is good
  • Heat treatment will not be able to harden the steel
  • The weldability is fair when welding thin gauges

Low carbon content and chromium will be found in the chemical composition

Chemical Composition

Class Type C Si Mn P S N Cr Mo Nb Ni
Utility 3CR12 0.03 1.0 2.0 0.040 0.030 10.5 - 12.5 0.3 - 1.5
Standard U-430 0.08 1.0 1.0 0.040 0.015 16.0 - 18.0 0.75
Moly U-434 0.08 1.0 1.0 0.040 0.015 16.0 - 18.0 0.9 - 1.25
U-436 0.08 1.0 1.0 0.040 0.015 0.040 16.0 - 18.0 0.8 - 1.25 7x(C+N)+0.1 to 0.8

Mechanical Properties (Hot Rolled)

Class Type Tensile Strength (MPa) 0.2 Proof Stress (MPa) Elongation (% in 50mm) General Corrosion Properties Pitting Corrosion Properties Formability Properties Toughness Welding Properties
Utility 3CR12 460 280 (<3), 300(≥3) 18 (≤4.5), 20(>4.5) Fair Fair Fair Good Good
Standard U-430 450-630 260 20 (≤1.27), 22(>1.27) Moderate Moderate Very Good Low Restricted
Moly U-434 450-630 280 22 Moderate Good Good Low Restricted
U-436 480-560 300 25 Very Good Very Good Very Good Low Restricted

Duplex

The duplex grade is a combination of the chemical composition of the Austenitic and Ferritic grades with the following advantages and characteristics

  • The corrosion resistance is excellent
  • Very good strength
  • Magnetic
  • Good weldability
  • Good formability
  • Cracking: stress and crevice corrosion

Chemical Composition

Class Type C Si Mn P S N Cr Mo Nb Ni
Lean U-2304 0.03 1.0 2.0 0.035 0.015 0.05 - 0.20 22.0 - 24.0 0.1 - 0.6 3.5 - 5.5
Standard U-2205 0.03 1.0 2.0 0.035 0.015 0.14 - 0.20 22.0 - 23.0 2.5 - 3.5 4.5 - 6.5

Mechanical Properties (Hot Rolled)

Class Type Tensile Strength 0.2 Proof Stress (MPa) Elongation (% in 50mm) General Corrosion Properties Pitting Corrosion Properties Formability Properties Toughness Welding Properties
Lean U-2304 630 - 800 400 25 Very Good Very Good Good Very Good Very Good
Standard U-2205 655 - 840 460 25 Excellent Excellent Good Very Good Very Good