Applications | Standards | Corrosion Resistance | Chemical Analysis
Mechanical Properties | Physical Properties | Heat Treatment | Processing
Welding | Machining

Alloy 17-4 PH is a precipitation hardening martensitic stainless steel with Cu and Nb/Cb additions. The grade combines high strength, hardness (up to 300°C / 572°F) and corrosion resistance.

Mechanical properties can be optimized with heat treatment. Very high yield strength up to 1100-1300 MPa (160-190 ksi) can be achieved.

The grade should not be used at temperatures above 300°C (572°F) or at very low temperatures. It has adequate resistance to atmospheric corrosion or in diluted acids or salts where its corrosion resistance is equivalent to grade 304 or 430.

• Offshore (foils, helicopter deck platforms, etc.)
• Food industry
• Pulp and paper industry.
• Aerospace (turbine blades, etc.)
• Mechanical components
• Nuclear waste casks

Standards
ASTM.....................A693 grade 630 (AMS 5604B) UNS S17400
EURONORM...........1.4542 X5CrNiCuNb 16-4
AFNOR...................Z5 CNU 17-4PH
DIN.........................1.4542

Corrosion Resistance
Alloy 17-4 PH withstands corrosive attacks better than any of the standard hardenable stainless steels and is comparable to type 304 in most media.

If there are potential risks of stress corrosion cracking, the higher aging temperatures then must be selected over 550°C (1022°F), preferably 590°C (1094°F). 550°C-1022°F is the optimum tempering temperature in chloride media.

590°C-1094°F is the optimum tempering temperature in H2S media.

The alloy is subject to crevice or pitting attack if exposed to stagnant seawater for any length of time.

It is corrosion resistant in some chemical, petroleum, paper, dairy and food processing industries (equivalent to 304L grade).

Mechanical Properties
Room temperature properties (longitudinal direction)

Guaranteed values (ASTM A693 hot rolled plates); thickness from 3/16" up to 3".

A: hardening 496°C (925°F) - 4 hours - air cooling
B: hardening 593°C (1100°F) - 4 hours - air cooling
2 examples of heat treatments that may be applied.
For specific requests, please contact us.

Elevated temperature properties

Minimum guaranteed values following EN 10088 hot rolled plates.
The EN guaranteed values are valid for a thickness from 3/16" up to 3".

Heat treatment : hardening 590°C (1094°F) - 4 hours - air cooling.
1 example of heat treatments that may be applied
For specific requests, please consult us.

Minimum guaranteed room temperature impact values

Minimum guaranteed values following ASTM A693 hot rolled plates.
The ASTM guaranteed values are valid for a thickness from 3/16" up to 3".

Minimum guaranteed room temperature hardness values

Minimum guaranteed values following ASTM A693 hot rolled plates.
The ASTM guaranteed values are valid for a thickness from 3/16" up to 3".

Physical Properties
Density : 7800 kg/m³ (.28 lbs/in³)

Following physical properties have been obtained after hardening 480°C (896°F) – 1 hour - air cooling.

Room temperature properties:
Resistivity : 80 µ_.cm
Specific heat : 460 J.kg^-1.K^-1
Tension modulus : 77 GPa
The alloy is magnetic.

 

Indicative values
Ms : 130°C (266°F)
Mf : 30°C (86°F)

Solution annealing

1050°C +/-25°C (1925°F+ /-50°F) – 30 min up to 1 hour.
air cooling / oil quenching below 25°C (76°F)

Aging / Tempering

The highest mechanical properties are obtained with the following heat treatment : 480°C (896°F) – 1 hour – air cooling.
Higher ductilities are obtained when using higher aging temperatures up to 620°C (1148°F).

Hardness/Temperature tempered for
4 hours after austenitizing at 1040°C (1904°F) for 30 min quenched 100°C/sec (212°F/sec)

Processing
Hot forming
Hot forming should be carried out in a temperature range of 950-1200°C (1742-2192°F). A full heat treatment including solution annealing, cooling lower than 25°C (76°F) and aging at the required temperature must be made after hot forming (function of the requested mechanical properties.

Cold forming
Cold forming can be performed only to a limited extent and only on plates in the fully softened condition. Stress corrosion resistance is improved by re-aging at the precipitation hardening temperature after cold working.

The following processes may be performed: rolling, bending, hydroforming, etc. (fully softened conditions)

Cutting
Thermal cutting (plasma, thermal sawing, etc.). Due to the HAZ, the grade requires a suited cutting process. After cutting, grinding is necessary to eliminate the oxide formed layer.

Mechanical cutting (shearing, stamping, cold sawing, etc.)

Welding
Alloy 17-4 PH can be welded by the following welding processes: SMAW, GTAW, PAW and GMAW. SAW should not be used without preliminary testing (to check freedom of cracks and thoughness of the weld metal).

Due to a ferrite delta primary type of solidification, the hot cracking risk of the weld metal or the HAZ is reduced.

Generally, no preheating must be done and interpass temperature must be limited to 120°C (248°F). The better toughness is obtained in the weld after a complete heat treatment (solution annealing + precipitation hardening).

Due to the martensitic microstructure, a low oxygen content in the weld metal is preferable to increase ductility and toughness. To avoid cold cracking, the introduction of hydrogen in the weld must be limited.

Alloy 17-4 PH can be welded with homogeneous filler metals such as E 630 (AWS A5.4) electrodes and ER 630 (AWS A5.9) wires.

Austenitic filler material can be used when the mechanical properties of 17-4 PH steel are not required in the weld and, in this case, no post weld heat treatment must be applied.

Machining
Alloy 17-4 PH can be machined in both solution treated and precipitation hardened conditions. Machining condition may vary according to the hardness of the material. High speed steel tools or preferably carbide tools with standard lubrification are normally used. If very stringent tolerances are required, it is necessary to take into account the dimensional changes during heat treatment.

NOTE
This technical data and information represents our best knowledge at the time of printing. However, it may be subject to some slight variations due to our ongoing research program on corrosion resistant grades.

We, therefore, suggest that information be verified at time of inquiry or order. Furthermore, in service, real conditions are specific for each application. The data presented here is only for the purpose of description and may only be considered as guarantees when our Company has given written formal approval.