17-4 Age-Hardening Martensitic Stainless Steel – Properties, Composition, Heat Treatments and Specifications from Super Alloys

Topics Covered

Background

17-4 Age-Hardening Martensitic Stainless Steel

Applications of 17-4 Stainless Steel

Composition of 17-4 Stainless Steel

Specifications

Heat Treatments for 17-4 Stainless Steel

Physical Properties of 17-4 Stainless Steel

Magnetic Permeability of 17-4 Stainless Steel

Thermal Properties of 17-4 Stainless Steel

Thermal Conductivity of 17-4 Stainless Steel

Typical Mechanical Properties of 17-4 Stainless Steel

Background

The Super Alloys management team are amongst the most experienced professionals in the market. Supported by professional metallurgists and technicians, Super Alloys not only provide access to the largest range of high-tec metals in Europe, but also access to the broadest range of expertise.

The unique combination of access to stock, expertise and rapid delivery reduces lead times and can eliminate costly production delays.

The Super Alloys range of materials includes:

         Titanium Alloys

         Nickel Alloys

         Steels

17-4 Age-Hardening Martensitic Stainless Steel

17-4 stainless steel  is an age-hardening martensitic alloy combining high strength with the corrosion resistance of stainless steel. Hardening is achieved by a short-time, simple low-temperature treatment. Unlike conventional martensitic stainless steels, such as type 410, 17-4 stainless steel is quite weldable. The strength, corrosion resistance and simplified fabrication can make 17-4 stainless steel a cost-effective replacement for high strength carbon steels as well as other stainless grades.

Applications of 17-4 Stainless Steel

Typical Applications for the 17-4 stainless steel age-hardening martensitic alloy include:

         Gate valves

         Aircraft structures, accessories, engine parts

         Chemical processing equipment

         Food processing machinery

         Pump shafts, gears, plungers

         Valve stems, balls, bushings, seats

         Pulp & paper mill equipment

         Fasteners

Composition of 17-4 Stainless Steel

The composition range for 17-4 stainless steel is provided in table 1.

Table 1. Composition of 17-4 Age-Hardening Martensitic stainless steel.

Chemistry, %

Min

Max

Chromium

15.00

17.50

Nickel

3.00

5.00

Copper

3.00

4.00

Manganese

-

1.00

Silicon

-

1.00

Columbium + Tantalum

5 x C

0.45

Carbon

-

0.07

Phosphorus

-

0.04*

Sulfur

-

0.03*

Molybdenum

-

0.05

Iron

remainder

* 0.025 max, AMS 5622

Specifications

The various forms of 17-4 stainless steel are covered by the following standards:

         UNS S17400 (Sheet, Plate, bar)

         UNS S17480 (MIG, TIG & Coil Weld Wire)

         UNS W37410 (Covered Electrodes)

         DIN 1.4548

Table 3. Specifications relating to 17-4 stainless steel.

Product Form

AMS

ASME

ASTM

AWS

Sheet Plate

5604

SA-693

A 693

 

Bar

5643

SA-564

A 564

 

Forgings

 

SA-705 Type 630

A 705 Type 630

 

Weld Wire (S17480)

5803

 

 

A5.9 ER 630

Weld Wire (W37410)

5827

 

 

A5.4 E630

Heat Treatments for 17-4 Stainless Steel

17-4 stainless steel is a martensitic, precipitation-hardening stainless steel. At the solution treating temperature, 1900°F (1040°C), the metal is austenitic but undergoes transformation to a low-carbon martensitic structure on cooling to room temperature. This transformation is not complete until the temperature drops to 90°F (32°C). Subsequent heating to temperatures of 900 to 1150°F (480 to 620°C) for one to four hours precipitation strengthens the alloy. This hardening treatment also tempers the martensitic structure, increasing ductility and toughness.

Physical Properties of 17-4 Stainless Steel

Table 4. Physical properties of 17-4 stainless steel.

Property

Value

Melting Range

2560-2625°F (1404-1440°C)

For Condition H 900 Density lb/in3

0.282

Electrical resistivity Ohm · circular mil/ft

463

Specific Heat Btu/lb°F

0.11

Poisson’s Ratio 70°F

0.272

Modulus of Elasticity psi x 106

 

Tension 70°F

28.5

200°F

28.0

400°F

27.0

600°F

26.0

Torsion 70°F

11.2

Magnetic Permeability of 17-4 Stainless Steel

H=100 Oersted

H=200 Oersted

Max

90

56

135

Thermal Properties of 17-4 Stainless Steel

The thermal properties of 17-4 stainless steel are summarised in table 5.

Table 5. Mean Coefficient of Thermal Expansion inch/inch°F x 10-6.

Temperature Range

Mean Coefficient of Thermal Expansion

-100 to 70°F

5.8

70 to 200°F

6.0

70 to 400°F

6.1

70 to 600°F

6.3

70 to 800°F

6.5

Thermal Conductivity of 17-4 Stainless Steel

The thermal conductivity of 17-4 stainless steel are summarised in table 3.

Table 6. Thermal Conductivity of 17-4 stainless steel in Btuft/ft²·hr·°F.

At 300°F

10.3

500°F

11.3

860°F

13.0

900°F

13.1

Typical Mechanical Properties of 17-4 Stainless Steel

Table 7. Typical mechanical properties of 17-4 stainless steel.

Property

Ultimate Tensile Strength

0.2% Yield Strength

Elongation % in 2"

Reduction of Area

Hardness

Impact

Charpy V-notch

 

ksi

ksi

or 4XD

%

Brinell

Rockwell

ft.-lbs.

H 900**

200

185

14

50

420

C 44

15

H 925

190

175

14

54

409

C 42

25

H 1025

170

165

15

56

352

C 38

35

H 1075

165

150

16

58

341

C 36

40

H 1100

150

135

17

58

332

C 35

25

H 1150

145

125

19

60

311

C 33

30

H 1150-M

125

85

22

68

277

C 27

100

 

Source: Super Alloys

 

For more information on this source please visit Super Alloys.

 

Date Added: May 13, 2008 | Updated: Jul 12, 2013
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