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A-21
A-21® is an advanced martensitic stainless steel with high surface hardness, core strength, toughness, ductility, and corrosion resistance. It is the only stainless carburizing steel that remains stainless where carburized.
Melt-type(s): VIM-VAR
Other name(s): N/A
Comparable grade(s): 9310, Jethete® M152, CX13VDW, XD16N, XD15NW®, Cronidur® 30 (AMS 5898), N360 (AMS 5898)
STANDARDS
| Type | Specifications |
|---|---|
| AMS | Pending |
| UNS | S41429 |
SIZES AVAILABLE
| Form | Size range |
|---|---|
| Bar | 1.125" - 7.000" |
CHEMICAL COMPOSITION
| Element | Range (%) |
|---|---|
| Al | 0.05 max |
| B | 0.01 max |
| C | 0.13 max |
| Co | 1.00 max |
| Cr | 10.50 - 14.00 |
| Cu | 0.50 max |
| Fe | Balance |
| Mn | 0.75 max |
| Mo | 0.40 - 0.80 |
| Nb | 0.20 max |
| Ni | 2.00 - 3.00 |
| P | 0.03 max |
| S | 0.03 max |
| Si | 1.00 max |
| Sn | 0.02 max |
| Ti | 0.15 - 0.75 |
| V | 0.25 max |
CHARACTERISTICS
| High temperature | Stainless | Through-hardened | Nitriding | Carburizing | Induction |
|---|---|---|---|---|---|
CHARACTERISTICS
| Characteristic | Value |
|---|---|
| High temperature | |
| Stainless | |
| Through-hardened | |
| Nitriding | |
| Carburizing | |
| Induction |
ADDITIONAL INFO
Mechanical property data for A-21®, provided by Carpenter, is listed below. QT160/130 = quenched & tempered and nitriding applications; C190/170 = carburized applications (VAR & VIM-VAR):
| Spec | Tensile KSI | Tensile MPa | Yield KSI | Yield MPa | Elongation % | R of A | HBW |
| QT160 | 160 | 1103 | 150 | 1034 | 16 | 50 | 33-38 |
| QT130 | 130 | 896 | 125 | 862 | 18 | 60 | 29-34 |
| C190 | 190 | 1310 | 145 | 1000 | 12-14 | 40-45 | 39 |
| C170 | 170 | 1172 | 135 | 1034 | 12-14 | 40-45 | 35 |
A-21® was tested against CPM S90V, Pyrowear® 675, and BG-42® in salt fog corrosion tests in the carburized and heat-treated condition. It performed well in humidity, salt spray, and stress corrosion cracking tests, and had moderate performance in sour oil/gas tests. The table below shows testing results:
| Corrosion Test | Average Corrosion Rate |
| ASTM B117 (Salt Fog) Quenched and tempered, salt bath nitrided |
None |
| ASTM D1735 (Humidity) Carburized, salt bath nitrided |
None |
| ISO 15156 (Sulfide Stress Cracking) Room temperature |
No failure |
| ASTM G129 (Stress Corrosion Cracking) Room temperature |
None |
Heat Treatment
Heat treatment instructions and recommendations for A-21® are provided by one of our mills, Carpenter. Please contact Sullivan Steel for additional guidance or information.
Machinability
Please contact Sullivan Steel for machinability information regarding A-21®.
Common Applications
Bearings, gears, actuators, splines, shafts, races, bolts, gun barrels, firing pins, drilling and workover rotors, housing, frack pumps, valve pumps, valve seats and trims, ball screws.
RESOURCES
Carpenter Data Sheet: A-21_Datasheet.pdf
DISCLAIMER
The product information provided on this page is provided for general reference only and is not complete. Customers and prospective customers should rely on the applicable material certifications for product information, including any exceptions to specifications, if applicable. Material certifications are available upon request. All product sales are subject to Sullivan Steel’s standard terms and conditions of sale.