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17-4Ph / 1.4542 / AISI 630 / UNS S17400 / AMS 5604 / AMS 5622

17-4 PH

UNS S17400 · W.Nr. 1.4542 · X5CrNiCuNb16-4 · AISI/Type 630 · 15.0-17.5% Cr – 3.0-5.0% Ni – 3.0-5.0% Cu – 0.15-0.45% Nb+Ta – C ≤ 0.07%

Not to be confused with

13-8Ph 15-5Ph 17-7Ph Custom 455

For what

Martensitic precipitation-hardening stainless steel. The part is machined in the solution-annealed state (Condition A), then brought to the required strength by a single aging cycle between 482 and 621 °C.

Forms

Round bar · Flat bar · Plate · Sheet · Pipe · Forging

Standards

AMS 5643 (bars, wire, forgings, mechanical tubing, rings) · AMS 5622 (same forms, consumable-electrode remelted) · AMS 5604 (sheet, strip, plate) · AMS 5825 (welding wire) · AMS 5827 (covered welding electrodes) · ASTM A564 / ASME SA-564 Type 630 (bars, wire, shapes) · ASTM A693 / ASME SA-693 Grade 630 (plate, sheet, strip) · ASTM A705 / ASME SA-705 Grade 630 (forgings) · EN 10088-3 1.4542
AMS 5643 and AMS 5622 cover the same UNS S17400 alloy; the difference is the melting route — AMS 5622 requires consumable-electrode remelted (ESR/VAR) material. AMS 5827G appears in the SAE catalogue as cancelled in September 2000;

Advantage

Strength is set by a single low-temperature cycle that requires no high-temperature quench. A part machined to finished size in Condition A is aged for 1-4 hours between 482 and 621 °C and air cooled, giving six different minimum yield levels from one alloy: 1170 MPa at H900 down to 725 MPa at…

Welding

Filler metal: for matching filler, AWS A5.9 ER630 (wire) / AWS A5.4 E630 (covered electrode); AMS equivalents are AMS 5825 and AMS 5827. Where base-metal strength is not required, austenitic AWS 308L is used — this filler does not respond to aging. Preheat: not normally required;

Limits

Continuous service temperature is limited to roughly 300-315 °C; prolonged exposure above this reduces toughness in the precipitation-hardened conditions. The H900 condition is markedly susceptible to chloride stress corrosion cracking;

REQUEST A QUOTE All precipitation hardening steels →TECHNICAL DETAILS ↓

Compiled from manufacturer data sheets · confirm against the current specification before ordering

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Standards by Product FormWelding, Heat Treatment and MachiningWhich Ageing Condition Should I Choose?Frequently Asked Questions

Corrosion resistance: 17-4 PH stands out for its superior corrosion resistance and offers resistance to rusting similar to that of grade 304 stainless steel. Although it is attracted by a magnet, that does not mean its corrosion resistance is low. It delivers long service life particularly in demanding environmental conditions.

Weldability: It can be welded readily by conventional methods and does not require preheating during welding. Care should be taken to avoid stresses in the design and welding of high strength steels.‌‌

Machinability: The hard internal and external structure of 1.4542 (17-4 PH) stainless steel can create some difficulties during machining. Post-production treatments improve the machinability of this steel. If heat treatment is to be applied, it is recommended that it be carried out after machining.

Heat treatment: It is produced and stocked in different heat treatment conditions depending on the application. Heat treatment options include PS800, P930, P960 and P1070 to European standards, and H1025, H1075, H1100 and H1150 to American standards.‌‌

Applications. Defence industry: chosen for its mechanical strength and long service life. Petrochemical industry: notable for its durability in chemical plants. Kitchen equipment: used for its corrosion resistance. Pump and valve shafts: its durable structure is ideal for producing parts of this kind.

1.4542 (17-4 PH / AISI 630) stainless steel is an indispensable material for many industries thanks to its wide range of applications and superior properties. Its durability, machinability and corrosion resistance make it a preferred solution.‌‌

Chemical Composition

C‌‌	Max. 0.070
Mn‌‌	Max. 1.00
Si‌‌	Max. 1.00
P‌‌	Max. 0.040
S‌‌	Max. 0.030
Cr‌‌	Min. 15.00 · Max. 17.50
Ni‌‌	Min. 3.00 · Max. 5.00
Cu‌‌	Min. 3.00 · Max. 5.00
Nb+Ta‌‌	Min. 0.15 · Max. 0.45

Mechanical Properties

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Tensile Strength (MPa)	1070-1270‌‌
Proof Stress (MPa)	1000‌‌
Elongation A50 mm	10‌‌
Hardness Brinell	363 Max HB‌‌
Density	7.75 g/cm3‌‌
Melting Point	1400-1440 °C‌‌
Modulus of Elasticity	197 GPa‌‌
Electrical Resistivity	800 nΩ.m‌‌
Thermal Conductivity	18.4 W/m-K‌‌
Thermal Expansion	10.8 µm/m°C‌‌

Standards and Equivalents · 17-4Ph

Trade name‌‌	17-4Ph
UNS‌‌	S17400
W.Nr (DIN/EN)‌‌	1.4542
AMS‌‌	5604 · 5622 · 5642 · 5643
ASTM‌‌	A484 · A564 · A693
Available forms‌‌	Round bar · Flat bar · Plate · Sheet · Tube · Forgings All forms are supplied to order.

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Standards by Product Form

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STANDARDS BY PRODUCT FORM

Product form	Standards
Round bar, flat bar‌‌	AMS 5643 · AMS 5622 (consumable-electrode remelted) · ASTM A564 / ASME SA-564 Type 630 · EN 10088-3 1.4542
Plate, sheet‌‌	AMS 5604 · ASTM A693 / ASME SA-693 Grade 630
Forging‌‌	AMS 5643 · ASTM A705 / ASME SA-705 Grade 630
Pipe, mechanical tubing‌‌	AMS 5643 (mechanical tubing scope) · ASTM has no seamless pressure pipe specification specific to 17-4 PH
Welding consumables‌‌	AMS 5825 (wire) / AWS A5.9 ER630 · AMS 5827 (covered electrode) / AWS A5.4 E630

The SAE catalogue shows AMS 5827G as cancelled in September 2000; confirm the current revision for aerospace orders. AMS 7474 (bolts) and ASTM F899 (surgical instrument steels) were found in only 2 sources and are not included in the map.

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The most common mistake when ordering 17-4 PH is quoting the specification without reference to the product form. The chemistry is identical in all three standards (Type 630, UNS S17400) and the condition codes are shared, but the mechanical minimums differ — the elongation minimum for sheet is markedly lower than for bar. “AISI 630” or “1.4542” alone is not an acceptance criterion; the product standard and the condition code must be stated together.

Standards by Product Form · 17-4 PH (S17400)

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Sheet · Plate · Strip	ASTM A693 Gr. 630 / ASME SA-693 · AMS 5604‌‌
Bar · Shapes	ASTM A564 Type 630 / ASME SA-564 · AMS 5643‌‌
Forgings	ASTM A705 / ASME SA-705 · AMS 5643‌‌
Wire	ASTM A564 (wire) · AMS 5643‌‌
Rings · Discs	AMS 5643‌‌
Seamless pipe · tube	AMS 5643 (there is no dedicated ASTM tubing standard)‌‌
Welding wire	AWS A5.9 ER630 · AMS 5825‌‌
Covered electrode	AWS A5.4 E630‌‌

Aerospace work uses AMS instead of ASTM: AMS 5604 for sheet and plate, AMS 5643 for bar, forgings, tubing and rings.

Ageing conditions and ASTM A564 / A705 minimum values (all air cooled, standard temperature tolerance ±8 °C):‌‌

Ageing Conditions · ASTM A564 / A705 Minimums

Condition A (solution annealed)‌‌	1038 ± 14 °C · ~30 min · rapid cool — a delivery condition, not a service condition
H900‌‌	482 °C · 1 h — yield ≥ 1170 MPa · tensile ≥ 1310 MPa · elong. ≥ 10% · ≥ 40 HRC
H925‌‌	496 °C · 4 h — yield ≥ 1070 MPa · tensile ≥ 1170 MPa · elong. ≥ 10% · ≥ 38 HRC
H1025‌‌	551 °C · 4 h — yield ≥ 1000 MPa · tensile ≥ 1070 MPa · elong. ≥ 12% · ≥ 35 HRC
H1075‌‌	579 °C · 4 h — yield ≥ 860 MPa · tensile ≥ 1000 MPa · elong. ≥ 13% · ≥ 32 HRC
H1100‌‌	593 °C · 4 h — yield ≥ 795 MPa · tensile ≥ 965 MPa · elong. ≥ 14% · ≥ 31 HRC
H1150‌‌	621 °C · 4 h — yield ≥ 725 MPa · tensile ≥ 930 MPa · elong. ≥ 16% · ≥ 28 HRC
H1150-M‌‌	760 °C / 2 h + 621 °C / 4 h — yield ≥ 520 MPa · tensile ≥ 795 MPa · elong. ≥ 18% · ≥ 24 HRC

These are ASTM A564 / A705 (bar and forgings) minimums, not typical values. For sheet and plate use the ASTM A693 table, where the elongation minimum is considerably lower.‌‌

Welding, Heat Treatment and Machining

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HEAT TREATMENT — SCHEMATIC

1 · SOLUTION TREATMENT

1040 °C ± 15 °C (1900 °F ± 25 °F)
minimum 30 minutes (after the centre reaches temperature)

2 · COOL

air, oil or water+polymer to below 32 °C (90 °F)

3 · AGEING

see the table below

Solution treatment

Step‌‌	Condition A (solution treated)
Temperature‌‌	1040 °C ± 15 °C (1900 °F ± 25 °F)
Time‌‌	minimum 30 minutes (after the centre reaches temperature)
Cooling‌‌	air, oil or water+polymer to below 32 °C (90 °F)

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H900

Step	H900‌‌
Temperature	482 °C (900 °F)‌‌
Time	1 hour‌‌
Cooling	air‌‌

H925

Step‌‌	H925
Temperature‌‌	496 °C (925 °F)
Time‌‌	4 hours
Cooling‌‌	air

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H1025

Step	H1025‌‌
Temperature	552 °C (1025 °F)‌‌
Time	4 hours‌‌
Cooling	air‌‌

H1075

Step‌‌	H1075
Temperature‌‌	579 °C (1075 °F)
Time‌‌	4 hours
Cooling‌‌	air

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H1100

Step	H1100‌‌
Temperature	593 °C (1100 °F)‌‌
Time	4 hours‌‌
Cooling	air‌‌

H1150

Step‌‌	H1150
Temperature‌‌	621 °C (1150 °F)
Time‌‌	4 hours
Cooling‌‌	air

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H1150-M

Step	H1150-M‌‌
Temperature	760 °C (1400 °F) → 621 °C (1150 °F)‌‌
Time	2 hours + 4 hours‌‌
Cooling	air cool after each cycle‌‌

H1150-D

Step‌‌	H1150-D
Temperature‌‌	621 °C (1150 °F), two separate cycles
Cooling‌‌	air cool after each cycle

This is a cycle schematic; no published TTT/CCT curve was used. The time axis is not to scale. Aging temperatures are Fahrenheit-based (H900 = 900 °F). Celsius equivalents differ by 1-2 °C between sources because of rounding: for example 550 °C (ASTM A564) versus 552 °C (manufacturer data sheets) for H1025. ATI and Jacquet give 1040-1065 °C for the solution treatment; ARMCO, ASTM A564, North American Stainless and Rolled Alloys state 1040 °C ± 15 °C. The H1150-D cycle time (4 hours + 4 hours) is stated explicitly in only 2 sources (ARMCO, Rolled Alloys), so it is not entered in the table; confirm it from the order specification. The Sandmeyer Steel page gives the H900 time as 4 hours and shows H1150D with the same cycle as H1150M; it conflicts with the other six sources and was not used.

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Welding

GTAW (TIG), GMAW (MIG), SMAW, plasma, electron beam and resistance welding are all applicable; oxy-acetylene welding is not recommended because of carbon pick-up. The matching filler is AWS A5.9 ER630 / A5.4 E630; where weld strength is not critical a ductile austenitic filler such as 308L is used, and ERNiCr-3 / ENiCrFe-3 for dissimilar joints. Welding is carried out in Condition A; for heavy or restrained sections welding in the H1100 or H1150 condition is preferred. Welding in H900 to H1075 is not recommended. Preheat is generally unnecessary; 100–150 °C helps on restrained joints. Post-weld heat treatment is required: a single-pass weld on Condition A can be aged directly, while a multi-pass weld must be solution annealed first and then aged.‌‌

Heat treatment

The alloy combines two mechanisms: transformation to low-carbon martensite after solution annealing, and precipitation of copper-rich particles during ageing. Solution annealing is carried out at 1038 ± 14 °C for about 30 minutes followed by rapid cooling below 32 °C, producing Condition A (around 33 HRC). Ageing is a single step between 482 and 621 °C for 1–4 hours, air cooled. Condition A is a delivery and machining condition, not a service condition — untempered martensite is more susceptible to stress-corrosion cracking in chloride environments. Cold forming can only be carried out in Condition A.‌‌

Machining

Machinability in Condition A is similar to Type 302/304; the best machinability is in H1150-M. Typical single-point turning speeds: Condition A and H1150-M, 24–29 m/min with HSS and 90–137 m/min with carbide; H1075–H1150, 18 m/min HSS and 76–122 m/min carbide; H900–H925, 9 m/min HSS and 49–76 m/min carbide. The material work-hardens readily — maintain a steady, adequate feed and never let the tool dwell on the workpiece. The most efficient route is to rough and finish in Condition A and age afterwards; dimensional change during single-step, low-temperature ageing is small, so distortion risk on precision parts is low.‌‌

Which Ageing Condition Should I Choose?

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STRENGTH BY AGEING CONDITION

Condition	Hardness	Yield MPa	Tensile MPa	Elongation
H900‌‌	≥ 40	1170‌‌	1310	10%‌‌
H925	≥ 38‌‌	1070	1170‌‌	10%
H1025‌‌	≥ 35	1000‌‌	1070	12%‌‌
H1075	≥ 32‌‌	860	1000‌‌	13%
H1100‌‌	≥ 31	795‌‌	965	14%‌‌
H1150	≥ 28‌‌	725	930‌‌	16%

All rows are ASTM A564/A564M Type 630 (ASME SA-564) STANDARD MINIMUM values — not manufacturer typical values. Values are for the bar product form. For sheet and strip (ASTM A693 / AMS 5604) the minimum elongation is lower — Ulbrich states 5% at H900 for sheet and strip. The hardness column is the ASTM A564 lower limit. Different publications vary by ±1-3 HRC at the lower limit (e.g. 34 HRC versus 35 HRC for H1025); the upper limit is set by the product form and the order specification. Manufacturer typical values are not included in this table; see the ‘atlananlar’ (omitted data) section for detail. The H1150-M and H1150-D rows are not in the table because the sources conflict; see the ‘celiskiler’ (conflicts) section.

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With 17-4 PH the real choice is not the alloy but the ageing condition. The rule is simple: select the highest ageing temperature that still meets the required strength, and do not go below 552 °C (H1025) where corrosion is a factor.

Selection Guide · Ageing Condition

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H900	Dry, atmospheric environments only; highest strength, most susceptible to stress-corrosion cracking‌‌
H1025	A good balance — high strength with markedly better stress-corrosion resistance‌‌
H1075 · H1100	Moderate strength, good toughness; preferred for welded parts‌‌
H1150 · H1150-M	Where toughness and corrosion resistance come first; best machinability‌‌
Chloride · seawater · H₂S	Do not use H900; age at 552 °C or above (H1025 and higher)‌‌

Where higher strength or a different balance is needed, 15-5 PH, 13-8 PH and Custom 455 are the other members of the same family.

Frequently Asked Questions‌‌

My material arrived in Condition A — can I use it as it is?

No. Condition A is a delivery and machining condition, not a service condition. The structure is untempered martensite: ductility is low and it is susceptible to stress-corrosion cracking in chloride environments. Machine the part in Condition A, then apply the ageing treatment (H900–H1150) appropriate to the service conditions.‌‌

Should I specify H900 or H1150?

If strength is the only requirement and the environment is dry and atmospheric, H900 (min. 1170 MPa yield). Where chlorides, seawater or H₂S are involved, do not use H900; manufacturers consistently recommend ageing at 552 °C or above. H1025 is a good balance (min. 1000 MPa yield with markedly better corrosion resistance); H1150 and H1150-M are chosen where toughness comes first. If the part is to be welded, the H1100 / H1150 class is required in any case.‌‌

Are ASTM A564, A693 and A705 interchangeable?

No — they cover different product forms: A564 bar, shapes and wire; A693 plate, sheet and strip; A705 forgings. The chemistry is the same in all three and the condition codes are shared, but the mechanical minimums differ. Quote the standard that matches the product form.‌‌

Related grades‌‌

17-7 PH · Custom 455 · 13-8 PH · 15-5 PH · Precipitation hardening steels →

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17-4Ph / 1.4542 / AISI 630 / UNS S17400 / AMS 5604 / AMS 5622

Standards by Product Form

Welding, Heat Treatment and Machining

Which Ageing Condition Should I Choose?

Frequently Asked Questions​‌​​‌​

Frequently Asked Questions‌‌