Martensitic Stainless Steel 410

Alloy 410 is a hardenable, straight-chromium stainless steel which combines the superior wear resistance of high carbon alloys with the excellent corrosion resistance of chromium stainless steels. Oil quenching this alloy from temperatures between 1800°F to 1950°F (982-1066°C) produces the highest strength and/or wear resistance as well as corrosion resistance. A range of as-quenched hardness is achieved by varying the carbon level from .15% maximum in Alloy 410.

 

 

Chemical Composition (wt%)

C

Mn

Si

Cr

0.15max

1.00max

1.00max

11.50-13.50max

 

Mo

Ni

S

P

/

0.50max

0.03max

0.04max

 

 

Physical Properties

Density (g/cm3)

7.65

Specific Heat (J/kg/°C)

460

Melting Point ()

1482-1532

Elastic Modulus @ R.T. (GPa)

200

Electrical Resistivity @ R.T (μΩ•cm .)

77

CTE (21 to 93 ) (μm/m)

9.9

Thermal Conductivity 100 (w/m)

24.9

The values reported above are typical for Alloy 410 in the annealed condition.

 

 

Mechanical Properties

Tensile Strength

Ultimate

0.2% Offset

Yield Strength

Elongation,

In 2”

Hardness

Rockwell B

517MPa

290MPa

25%

80

The values reported above are typical for Alloy 410 in the annealed condition.

 

 

Data shown below give typical mechanical properties of martensitic stainless steels obtained with various drawing temperatures after austenitizing at 1800-1950°F (982-1066°C) followed by an oil quench and a two-hour temper. Heat-to-heat variations can be anticipated.

 

Heat

Treatment

T410(0.14%C) Hardened 982

Rockwell Hardness

 

Rockwell Hardness

Annealed*

81HRB

Annealed*

81HRB

Hardened & Tempered 204

43HRC

Hardened & Tempered 204

43HRC

Hardened & Tempered 288

40HRC

Hardened & Tempered 288

40HRC

Hardened & Tempered 316

40HRC

Hardened & Tempered 316

40HRC

Hardened & Tempered 427

41HRC

Hardened & Tempered 427

41HRC

Hardened & Tempered 482

41HRC

Hardened & Tempered 482

41HRC

Hardened & Tempered 538

35HRC

Hardened & Tempered 538

35HRC

Hardened & Tempered 649

98HRC

Hardened & Tempered 649

98HRC

 

 

Principal Design Features

410 is the basic martensitic stainless which will attain high mechanical properties after heat treatment. This alloy is used where strength, hardness, and/or wear resistance must be combined with corrosion resistance. Alloy 410 resists corrosion in mild atmospheres, steam, and many mild chemical environments. The alloy can be heat treated to obtain high strength with good ductility.

 

When sufficient amounts of carbon are added to straight-chromium stainless steels, the alloy then has the capability to transform its microstructure through proper heat treatment (hardening) into one that will possess optimum strength, hardness, edge retention, and wear resistance. The presence of sufficient chromium will impart the necessary corrosion resistance and form chromium carbine particles that enhance the wear resistance of the given alloy. The higher the carbon content, the greater the amount of chromium carbide particles, and the greater the strength and hardness for heat treatable straight-chromium stainless steels.

 

 

Corrosion Resistance

Alloy 410 exhibits good corrosion resistance to atmospheric corrosion, potable water, and to mildly corrosive chemical environments because of its ability to form a tightly adherent oxide film which protects its surface from further attack. Its exposure to chlorides in everyday-type activities (e.g., food preparation, sports activities, etc.) is generally satisfactory when proper cleaning is performed after exposure to use.

 

Surface Preparation

For maximum corrosion resistance to chemical environments, it is essential that the stainless steel surface be free of all heat tint or oxide formed during forging, annealing, or heat treating. All surfaces must be ground or polished to remove any traces of oxide and surface decarburization. The parts should then be immersed in a warm solution of 10-20% nitric acid to remove any residual iron. A thorough water rinse should follow the nitric acid treatment.

 

General Corrosion Behavior Compared With Other Nonaustenitic Stainless Steels*

5% Solution at 120°F (49°C)

Corrosion Rate in m per Year

SS 409

SS 410

SS 420

SS 425

SS 440A

SS 430

Acetic Acid

22

2

28

122

58.6

0.6

Phosphoric Acid

2

2

2

15

9

1

*Hardened martensitic grades were tested after tempering at 400°F (204°C).

As shown in the above table, these alloys have good corrosion resistance to low concentrations of mild organic and mineral acids.

 

 

Heat Treating

To anneal this alloy, heat to 1500°F-1550°F (815-842°C) and hold for one hour per inch of thickness and furnace cool to room temperature. Such annealing should produce a Brinell hardness of 126-192 HB in Alloy 410 material. A hardening heat treatment is necessary to bring out the maximum hardness and wear resistance. Since these materials absorb heat very slowly, they should be heated gradually and allowed to remain at temperature long enough to ensure uniform temperature in thick sections. For maximum strength, hardness, and corrosion resistance, slowly heat the alloy to 1800°F (982°C) and quench to room temperature in oil.

 

Micro-Structure

In the annealed condition, Alloy 410 consists of ferrite and carbides. When this alloy is heat treated at high temperatures [1800°F-1950°F (982-1066°C)], austenite will form and transform to martensite upon cooling to room temperature (i.e., air cool or oil quench). The hardness of the martensite will increase with increasing carbon content to a point where the martensite becomes saturated with carbon. Carbon also combines with carbide formers such as chromium to form chromium carbides which are dispersed throughout the microstructure to provide added wear resistance, as does higher hardness.

 

 

Machinability

Tough, drag chips with heavy build-up. While this alloy can be machined in the annealed condition, it tends to perform better in the cold drawn or heat treated condition.

 

 

Welding

Most common methods of welding can be successfully employed with this alloy. To reduce the chance of cracking, it is advisable to preheat the work piece to 350-400 F (177-204 C). Post-weld annealing is recommended to retain maximum ductility. Filler metal, when required, should be AWS E/ER410.

 

 

Hot Working

2000-2200 F (1093-1204 C) is the proper hot work range. Do not work this material below 1650 F (899 C).

 

 

Cold Working

Readily cold formed using most of the common practices.

 

 

Applications

Applications for Alloy 410 include dental and surgical instruments, nozzles, valve parts, hardened steel balls and seats for oil well pumps, separating screens and strainers, springs, shears, and wear surfaces.