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 |