A-21 (AMS PENDING)

A-21 an advanced martensitic stainless steel produced via vacuum induction melt and vacuum arc remelting processes. Known for its high strength and toughness, A-21 is often used in structural applications where corrosion, fatigue, and temper resistance are required–particularly useful for applications spanning industries such as aerospace, defense, energy, industrial, and transportation.

MELT PRACTICE: VIM-VAR
SPECIFICATIONS:
AMS PENDING

ABOUT A-21

A-21 provides high performance stainless properties in the carburized, nitrided, and quenched and tempered conditions. As the world’s only stainless carburizing steel that remains stainless in the areas it is carburized, A-21 provides a deep, hard, stainless case with a strong, tough, and ductile core, and is often considered the stainless version of 9310 or 8620. In the ferritic carbo-nitrided condition, A-21 retains its stainless properties and boasts very high surface hardness, while nitriding is typically performed on finished parts with minimal distortion.

GET A-21 AT SULLIVAN STEEL

Grade Type Size
A-21 VIM-VAR 1.125" - 7.000"

Chemical Composition – VIM-VAR

C Mn Si Cr Ni Mo V Mn
0.13% max 0.75% max 1.00% max 10.50-14.00% 2.00-3.00% 0.40-0.80% 0.25% max 0.75% max

HEAT TREATMENT

ANNEALING: 1,100 - 1,200°F (593 - 649°C)

HARDENING: 1,550 - 1,600°F (843 - 871°C)

NORMALIZING: 1,600 - 1,650°F (871 - 899°C)

TEMPERING: 200 - 1,200°F (93 - 649°C)

MECHANICAL PROPERTY DATA

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

 

QT160/130 = quenched & tempered and nitrided applications

C190/170 = carburized applications (VAR and VIMVAR)

CORROSION RESISTANCE

A-21 outperforms conventional stainless steel, CPM S90V, P675, and BG-42 in salt fog corrosion tests in the carburized and heat treated condition. It also performed exceptionally well in humidity, salt spray, and stress corrosion cracking tests, and had moderate performance in sour oil/gas tests.

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

APPLICATIONS

  • Carburized bearings, gears, actuators, splines, shafts, races
  • Carburized bolts, gun barrels, bolt carriers, firing pins
  • Drilling and workover rotors, housings, frack pumps, valve pumps
  • Valve seats and trims, ball screws

    PURCHASE A-21 STEEL

    Sullivan Steel stocks A-21 in 1.125” to 7.000”. Want to learn more about A-21 and how it might fit into your application? We are here to provide guidance and technical support for your project–just speak to one of our experts.

    Already know your requirements and just want to purchase A-21? Request a quote now!

 

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