4.2.2 Austenitic Grades

Austenitic grades contain 8% to 18% of nickel in addition to typically 18% to 20% chromium. They cannot be hardened by heat treatment, but can be hardened by cold working, and excellent properties are developed in the grades with lower nickel content. This class is highly resistant to many acids, and alloys in this family exhibit excellent impact toughness at cryogenic temperatures, as low as liquid nitrogen (-200°C or -325°F). Alloys with higher (25%) chromium can be used at temperatures up to 1095°C (2000°F) without excessive scaling. Two types, 304L and 316L have carbon contents below 0.03%, and are specified where welding is required and postannealing is impractical.

Commonly used austenitic forging grades include:

SAE
No
AMS
No
Percent Composition
Cb Cr Mo Ni Ta Ti  
302 A4732     18     8  
304 A4732     18     9  
310 5651     25     20  
316 5648     18 2.5   12  
321 5645     18     9 1
347 5653     18     10 1

 

1 Indicates minor amounts, depending on carbon content
2 ASTM specification

SAE standards list several other grades that have special purposes and, while not as commonly forged, are just as forgeable as these listed grades. 303 is not a common forging alloy because its sulphur causes problems.

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Austenitic grades contain 8% to 18% of nickel in addition to typically 18% to 20% chromium. They cannot be hardened by heat treatment, but can be hardened by cold working, and excellent properties are developed in the grades with lower nickel content. This class is highly resistant to many acids, and alloys in this family exhibit excellent impact toughness at cryogenic temperatures, as low as liquid nitrogen (-200°C or -325°F). Alloys with higher (25%) chromium can be used at temperatures up to 1095°C (2000°F) without excessive scaling. Two types, 304L and 316L have carbon contents below 0.03%, and are specified where welding is required and postannealing is impractical.

Commonly used austenitic forging grades include:

SAE
No
AMS
No
Percent Composition
Cb Cr Mo Ni Ta Ti  
302 A4732     18     8  
304 A4732     18     9  
310 5651     25     20  
316 5648     18 2.5   12  
321 5645     18     9 1
347 5653     18     10 1

 

1 Indicates minor amounts, depending on carbon content
2 ASTM specification

SAE standards list several other grades that have special purposes and, while not as commonly forged, are just as forgeable as these listed grades. 303 is not a common forging alloy because its sulphur causes problems.

Return to Table of Contents

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Austenitic grades contain 8% to 18% of nickel in addition to typically 18% to 20% chromium. They cannot be hardened by heat treatment, but can be hardened by cold working, and excellent properties are developed in the grades with lower nickel content. This class is highly resistant to many acids, and alloys in this family exhibit excellent impact toughness at cryogenic temperatures, as low as liquid nitrogen (-200°C or -325°F). Alloys with higher (25%) chromium can be used at temperatures up to 1095°C (2000°F) without excessive scaling. Two types, 304L and 316L have carbon contents below 0.03%, and are specified where welding is required and postannealing is impractical.

Commonly used austenitic forging grades include:

SAE
No
AMS
No
Percent Composition
Cb Cr Mo Ni Ta Ti  
302 A4732     18     8  
304 A4732     18     9  
310 5651     25     20  
316 5648     18 2.5   12  
321 5645     18     9 1
347 5653     18     10 1

 

1 Indicates minor amounts, depending on carbon content
2 ASTM specification

SAE standards list several other grades that have special purposes and, while not as commonly forged, are just as forgeable as these listed grades. 303 is not a common forging alloy because its sulphur causes problems.

Return to Table of Contents

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