AISI 630 Stainless steel (17-4 Precipitation Hardening | 17-4 PH) | W.Nr 1.4542 ) is a martensitic chromium-nickel-copper stainless steel. The name of 17-4 PH comes from the additions 17% Chromium and 4% Nickel. It also contains 4% Copper and 0.3% Niobium. Precipitation hardening steels are characterised into one of three groups based on their final microstructures after heat treatment. The three types are: martensitic (e.g. 17-4 PH), semi-austenitic (e.g. 17-7 PH) and austenitic (e.g. A-286).

The advantage of precipitation hardening steels is that they can be supplied in a “solution treated” condition, which is readily machinable. After machining or another fabrication method, a single, low temperature heat treatment can be applied to increase the strength of the steel. This is known as ageing or age-hardening. As it is carried out at low temperature, the component undergoes no distortion.

17-4 PH that also known as stainless steel grade 630 is a chromium-copper precipitation hardening stainless steel used for applications requiring high strength and a moderate level of corrosion resistance.

High strength is maintained to approximately 600 degrees Fahrenheit (316 degrees Celsius). 17-4 PH/ grade 630 can operate in the temperature range from -29 ℃ to 343 ℃, while retaining relatively good parameters. In addition, the materials in this grade are characterized by relatively good ductility and their corrosion resistance is comparable to alloy 304 or 430.

17-4 PH is manufactured in several strength levels, for example: in solution annealed (AT) and hardened versions (H900, H925, H1025, H1075, H1100, H1150, H1150M). AISI 630 is a hardenable, martensitic stainless steel with high wear resistance, good corrosion resistance and high yield strength. Mechanical properties can be optimized with heat treatment. Very high yield strength up to 1100-1300 MPa (160-190 ksi) can be achieved.

AISI 630 (17-4 PH) can be welded by TIG, but the welding process requires the use of an annealed material. Otherwise the material at the joints will not retain the proper structure. Furthermore, at the expense of a slight loss of corrosion resistance, the products can be nitrided to achieve a hardened topcoat.

Grade 630 is used in the aerospace, chemical, petrochemical and petroleum industries, in medical and dental technology, in plant construction and in shipbuilding. The material is also widely used in the marine, paper, energy, offshore and food industries for heavy-duty machine components, bushings, turbine blades, couplings, screws, drive shafts, nuts, measuring devices. By combining excellent mechanical properties and high corrosion resistance, AISI 630 can be used in a marine environment, but in standing seawater it is susceptible to crevice corrosion.

Composition ranges for grade AISI 630 stainless steels | 17-4 PH :

GradeCMnSiPSCrNiCuNb+Ta
630min.
max

0.07

1

1

0.04

0.030
15
17.5
3
5
0.15
0.45

Mechanical Properties Specification

Condition

Hardening

Tensile Strength (MPa)

Yield Strength 0.2% Proof (MPa)

Elongation (% in 50mm)

Hardness

Temp (°C)

Time (h)

Rockwell C (HR C)

Brinell

(HB)

A

1105 typ.

1000 typ.

15 typ.

38 max

363 max

H900

480

1

1310

1170

10

40

388

H925

495

4

1170

1070

10

38

375

H1025

550

4

1070

1000

12

35

331

H1075

580

4

1000

860

13

32

311

H1100

595

4

965

795

14

31

302

H1150

620

4

930

725

16

28

277

Single property values are minima except as noted as typical or maximum.

Values from ASTM A564M; these values apply only to certain size ranges. The specification should be consulted for the complete details of these properties and of heat treatment procedures.

Solution treatment is at 1040°C followed by cooling as required.

Specialist double-aging treatments H1150M and H1150D are also possible – refer to ASTM A564M.

 

Physical Properties

                                                                  

Grade

Density (kg/m3)

Elastic Modulus

(GPa)

Mean Coefficient of Thermal Expansion

Thermal Conductivity

Specific Heat

0-100°C

( J/kg.K)

Electrical Resistivity

(nΩ.m)

0-100°C

(μm/m/°C)

0-315°C

(μm/m/°C)

0-538°C

(μm/m/°C)

at 100°C (W/m.K)

at 500°C (W/m.K)

630

7750

196

10.8

11.6

18.4

22.7

460

800

  typical values in the annealed condition)

Grade Specification Comparison

Grade

UNS

No

Euronorm

Swedish SS

Japanese JIS

No

Name

630

S17400

1.4542

X5CrNiCuNb16-4

SUS 630

These comparisons are approximate only. The list is intended as a comparison of functionally similar materials not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted.

 

Possible Alternative Grades

GradeWhy it might be chosen instead of 630 (17-4PH)
431431 has higher toughness than 630. Better availability in some sizes.
416Free machining martensitic stainless steel – better machinability. Lower cost but lower corrosion resistance.
316Higher corrosion resistance of 316 is needed, but with much lower strength than 630.
2205Much better corrosion resistance than 630, with a lower strength (but not as low as 316).

The information contained in this article about AISI 630 stainless steel – 17-4 PH is not an exhaustive statement of all relevant information. It is a general guide for customers to the products and services available from Steelindo Persada and no representation is made or warranty given in relation to this document or the products or processes it describes.

References:

  • https://www.azom.com
  • http://www.specialtysteelsupply.com
  • https://www.stahlportal.com
  • https://virgamet.com/
  • https://www.aalco.co.uk
  • https://www.atlassteels.com.au
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