Trademark notice: 17-4 PH®, 15-5 PH®, 17-7 PH®, PH 13-8 Mo®, and Nitronic® are registered trademarks of Cleveland-Cliffs Inc. (formerly AK Steel / Armco). Inconel® is a registered trademark of Special Metals Corporation, and Hastelloy® is a registered trademark of Haynes International, Inc. Material made by those companies and sold under those brand names is theirs. Material we produce is correctly described as UNS S17400 / ASTM A564 Type 630 / AMS 5643 / DIN 1.4542 — the same generic chemistry, manufactured independently by Jiangyin Jiangnan Metal Co., Ltd. We are not affiliated with, sponsored by, or endorsed by any of the trademark holders listed above. All other product names, brand names, and trademarks referenced are the property of their respective owners.
Jiangyin Jiangnan Metal manufactures 17-4PH / UNS S17400 forgings via four process routes, selected by part geometry and order volume. Open-die forging is used for long shafts, blocks, and large forged discs up to 8 m length or 8 tonnes single-piece weight. Seamless ring rolling produces 17-4PH forged rings from 200 mm to 2,500 mm outside diameter — the most common route for valve flanges, pressure-housing rings, and rolled-ring blanks supplied to EN 1.4542 or AMS 5643 chemistry. Closed-die forging handles repeat-volume parts such as pump impellers and valve trim where dimensional consistency outweighs maximum size. Upset forging is reserved for short, large-cross-section discs and hubs. Near-net-shape forging typically reduces machining stock by 30–50% on complex profiles like valve bodies and yoke arms, lowering both raw-material cost and lead time. For hollow shafts with bore diameter above ~100 mm, the input bar may be supplied as a trepanned billet to reduce raw-material weight and machining time. All routes produce finished parts to ASTM A564 / A705 Type 630, AMS 5643, EN 1.4542, or JIS SUS 630 as the drawing requires.
The 17-4PH alloy has a 75-year industrial history. Understanding its evolution helps procurement engineers appreciate why certain specifications (especially aerospace AMS 5643 and NACE H1150-M) exist as they do today.
17-4PH (AISI 630 / UNS S17400 / ASTM A564 Type 630 / AMS 5643 / DIN 1.4542 / SUS 630) is the most widely used precipitation-hardening martensitic stainless steel. Its nominal composition — 17%Cr, 4%Ni, 3–5%Cu, with niobium / tantalum stabilizer — produces a martensitic microstructure on cooling from solution treatment, which is then strengthened by a final low-temperature aging step that precipitates copper-rich (ε-Cu) particles throughout the matrix. The result is a stainless steel with strength competitive with medium-carbon alloy steels (up to 1,310 MPa UTS / 190 ksi) while retaining good corrosion resistance similar to Type 304.
The defining feature of 17-4PH is the tunable strength-vs-toughness trade-off available through choice of aging temperature. The H-number (e.g. H900, H1025, H1150) denotes the aging temperature in °F. Higher aging temperatures produce lower strength but higher impact toughness, better stress-corrosion cracking resistance, and improved ductility. This single-grade flexibility is why 17-4PH dominates pump and valve industries (which need high strength + corrosion resistance), aerospace structural parts, marine hardware, food and chemical processing equipment, and many specialty industrial applications.
17-4PH is martensitic and therefore magnetic in all conditions (μᵣ ≈ 95 typical) — distinguishing it from the austenitic Cr-Ni stainless grades. It should not be used for prolonged service above ~315 °C (600 °F), since aging-temperature exposure will over-age the precipitates and reduce strength. For higher service temperatures, see our A286 / UNS S66286 page.
17-4PH is sold under multiple designations depending on the specifying body. Engineers searching for any of the following names below the trademark line are referring to the identical chemistry, and Jiangyin Jiangnan Metal Co., Ltd. accepts purchase orders under all of them — supplying UNS S17400 / ASTM A564 Type 630 forgings that meet the equivalent specifications:
| Standard / Body | Designation | Region / Notes |
|---|---|---|
| USA · Brand (Cleveland-Cliffs trademark) | 17-4 PH® | Registered trademark of Cleveland-Cliffs Inc. We do not sell under this name; we ship the generic equivalents below. |
| USA · UNS | UNS S17400 | Generic Unified Numbering System designation |
| USA · AISI (legacy) | AISI 630 | Legacy American Iron and Steel Institute designation — still widely used on drawings and datasheets |
| USA · ASTM (bars/forgings) | ASTM A564 Type 630 | Hot-rolled and cold-finished bars / shapes |
| USA · ASTM (sheet/plate) | ASTM A693 Type 630 | Sheet, strip, plate |
| USA · ASTM (forgings) | ASTM A705 Gr 630 | Forging-specific spec |
| USA · AMS (bars/forgings) | AMS 5643 | Bars, forgings, tubing, rings — most common aerospace spec |
| USA · AMS (sheet/strip) | AMS 5604 | Sheet and strip |
| USA · AMS (alternate bars) | AMS 5622 | Bars, alternate spec |
| USA · ASME BPVC | SA-564 Type 630 / SA-705 Gr 630 | Pressure vessel code equivalents |
| EU · DIN / EN | 1.4542 / X5CrNiCuNb16-4 | European designation per EN 10088-3 |
| Japan · JIS | SUS 630 | JIS G 4303 / G 4318 |
The 17-4PH chemistry below is per ASTM A564 Type 630 / A705 Grade 630, and is essentially identical across AMS 5643, AMS 5604, AMS 5622, and DIN 1.4542. The chromium provides corrosion resistance; the low nickel + copper stabilizes martensite with precipitation-strengthening capability; the niobium + tantalum addition prevents chromium-carbide sensitization and aids precipitation control during aging.
| Element | Min | Max | Role |
|---|---|---|---|
| Carbon (C) | — | 0.07 | Strength contribution; capped low to maintain corrosion resistance |
| Manganese (Mn) | — | 1.00 | Deoxidizer |
| Silicon (Si) | — | 1.00 | Deoxidizer |
| Phosphorus (P) | — | 0.040 | Impurity |
| Sulfur (S) | — | 0.030 | Impurity |
| Chromium (Cr) | 15.00 | 17.50 | Corrosion resistance, martensite stabilizer |
| Nickel (Ni) | 3.00 | 5.00 | Toughness, martensite-finish temperature control |
| Copper (Cu) | 3.00 | 5.00 | Primary precipitation-hardening element (ε-Cu phase) |
| Niobium + Tantalum (Nb+Ta) | 0.15 | 0.45 | Stabilizer; precipitation control during aging |
| Iron (Fe) | Balance | Matrix | |
The table above shows the ASTM A564 Type 630 chemistry — the most common reference for 17-4PH. However, EN 1.4542, JIS SUS 630, and AMS 5643 have subtle but real differences in element limits and test requirements. Most competitor pages claim these are identical; technically they're not. Jiangyin Jiangnan Metal Co., Ltd. produces material to the most restrictive limits where required, so a single heat can satisfy multiple specifications simultaneously on the MTC.
| Element | ASTM A564 Type 630 (USA) |
AMS 5643 (USA aerospace) |
EN 1.4542 (Europe) |
JIS SUS 630 (Japan) |
|---|---|---|---|---|
| Carbon (C) | 0.07 | 0.07 | 0.07 | 0.07 |
| Silicon (Si) | 1.00 | 1.00 | 0.70 | 1.00 |
| Manganese (Mn) | 1.00 | 1.00 | 1.50 | 1.00 |
| Phosphorus (P) | 0.040 | 0.040 | 0.040 | 0.040 |
| Sulfur (S) | 0.030 | 0.030 (often ≤0.015 by spec) | 0.015 | 0.030 |
| Chromium (Cr) | 15.00–17.50 | 15.00–17.50 | 15.00–17.00 | 15.00–17.50 |
| Nickel (Ni) | 3.00–5.00 | 3.00–5.00 | 3.00–5.00 | 3.00–5.00 |
| Copper (Cu) | 3.00–5.00 | 3.00–5.00 | 3.00–5.00 | 3.00–5.00 |
| Niobium + Ta (Nb+Ta) | 0.15–0.45 | 0.15–0.45 | ≤0.45 (no min) | 0.15–0.45 |
| Molybdenum (Mo) | not specified | not specified | ≤0.60 (allowed) | not specified |
| Nitrogen (N) | not specified | not specified | not specified, but typically ≤0.05 | not specified |
Bottom line on chemistry: a single 17-4PH heat that meets EN 1.4542 (the most restrictive on S and Si) will automatically satisfy ASTM A564, AMS 5643, and JIS SUS 630 simultaneously — except for the EN-allowed Mo, which is a non-issue if Mo content is verified low. Our standard practice is to procure raw stock to the strictest applicable limit and issue a multi-designation MTC.
Minimum mechanical properties (UTS, YS, elongation, RA, hardness) are essentially identical across all four standards for the same H-condition. The real differences lie in which tests are required, in which direction, and what NDE is performed.
| Test / Requirement | ASTM A564 (general bars) |
AMS 5643 (aerospace) |
EN 10088-3 (EU bars) |
JIS G 4303 (JP bars) |
|---|---|---|---|---|
| Tensile (longitudinal) | Required | Required | Required | Required |
| Tensile (transverse) | Not required | Required (cleaner ratio) | Optional | Optional |
| Hardness (HRC / HB) | Required per condition | Required per condition | Required in HB (Brinell) | Required HRC |
| Charpy impact | Optional (per buyer) | Required, tight limits | Optional | Optional |
| Grain flow / macroetch | Optional | Required for forgings | Optional | Optional |
| Vacuum / clean melt | Not required | Required (VIM/VAR or AOD) | Not required | Not required |
| UT (ultrasonic) NDT | Per ASTM A388 | Per AMS-STD-2154 Class A | Per EN 10228 | Per JIS G 0801 |
| PT / MT surface NDT | Per ASTM E165 / E1417 | Per ASTM E1417 Type I Method C, Sens Level 3+ | Per EN ISO 3452 | Per JIS Z 2343 |
| Inclusion rating | Per ASTM E45 (if ordered) | Per AMS 2301 / 2304 | Per ISO 4967 | Per JIS G 0555 |
| Heat-treat traceability | Heat number only | Lot-level chart recordings | Heat + cast number | Heat + cast number |
| Cert format | EN 10204 3.1 typical | EN 10204 3.1 or 3.2 + AMS source approval | EN 10204 3.1 / 3.2 | Mill test report |
For customers who need cross-border traceability, we supply single-heat material certified to multiple standards simultaneously. The MTC (Material Test Certificate) lists:
Practical takeaway: If you don't know which standard to specify, ASTM A564 Type 630 (for bars) or ASTM A705 Gr 630 (for forgings) is the safest default. We will cross-certify to EN 1.4542 and JIS SUS 630 on the same MTC at no extra cost. AMS 5643 aerospace certification is a separately priced lot due to the additional testing burden.
17-4PH mechanical properties depend strongly on the aging condition. The H-number is the aging temperature in °F. The table below summarizes minimum properties per ASTM A564 / A705 for all standard H-conditions, plus Condition A (solution annealed only). Values are for longitudinal tests on bars / forgings up to 75 mm thick; thicker sections may show slightly reduced properties.
| Condition | Aging Temp | UTS Min | YS Min (0.2%) | El. Min % | RA Min % | Hardness |
|---|---|---|---|---|---|---|
| H900 | 482 °C (900 °F) | 1,310 MPa (190 ksi) | 1,170 MPa (170 ksi) | 10 | 40 | ~40 HRC |
| H925 | 496 °C (925 °F) | 1,170 MPa (170 ksi) | 1,070 MPa (155 ksi) | 10 | 44 | ~38 HRC |
| H1025 | 552 °C (1025 °F) | 1,070 MPa (155 ksi) | 1,000 MPa (145 ksi) | 12 | 45 | ~35 HRC |
| H1075 | 580 °C (1075 °F) | 1,000 MPa (145 ksi) | 860 MPa (125 ksi) | 13 | 45 | ~32 HRC |
| H1100 | 593 °C (1100 °F) | 965 MPa (140 ksi) | 795 MPa (115 ksi) | 14 | 45 | ~31 HRC |
| H1150 | 621 °C (1150 °F) | 930 MPa (135 ksi) | 725 MPa (105 ksi) | 16 | 50 | ~28 HRC |
| H1150-M (double-aged) | 760 °C/2h + 621 °C/4h | 795 MPa (115 ksi) | 515 MPa (75 ksi) | 18 | 55 | ~24 HRC |
| Condition A (sol only) | — | 1,030 MPa (150 ksi) | 760 MPa (110 ksi) | 5 | — | ≤38 HRC |
Choosing the correct aging condition is the most important specification decision for any 17-4PH forging order. The table below summarizes typical applications and trade-offs.
| Condition | Choose this when… | Avoid this if… | Typical Industries |
|---|---|---|---|
| H900 | Maximum strength / hardness needed; static loading | Impact, fatigue, or chloride SCC are concerns | Tooling, fasteners, knives |
| H925 | Slight toughness improvement vs H900 | Less common — usually H900 or H1025 is chosen | Aerospace, fasteners |
| H1025 | Best general-purpose balance of strength and toughness | Severe chloride SCC environment present | Aerospace structural, valve bodies, general industrial |
| H1075 | Pump shafts where fatigue and corrosion fatigue matter | Very high static loading required (use H900/H1025) | Pump industry (chemical, water) |
| H1100 | Larger sections needing through-aging consistency | Highest yield strength is required | Heavy industrial, oil & gas |
| H1150 | Best impact toughness and chloride SCC resistance | High-stress applications above ~700 MPa YS need a higher condition | Marine, chemical, severe service |
| H1150-M (double-aged) | Maximum impact toughness; severe-service downhole | Strength is the primary criterion | Oil & gas downhole, NACE applications |
Aging cycle reminder: aging is performed AFTER solution treatment (1040 °C + air cool to room temperature) and AFTER all rough machining. Aging dimensional change is typically <0.1% but may need to be allowed for in critical-dimension parts.
The following three worked examples demonstrate how 17-4PH mechanical data feeds into real engineering decisions. They are simplified for clarity; production designs require finite-element verification and applicable code factors.
A vertical centrifugal pump shaft, 17-4PH H1075, must be checked against its first lateral critical speed.
A high-pressure valve stem, 17-4PH H1025, must resist axial compression from seat seating force without buckling.
A 17-4PH H1025 component sees fluctuating tensile stress. Determine whether infinite-life fatigue criterion is met.
These worked examples are simplified educational examples. Actual production designs must consider: temperature derating, multi-axial stress, environmental factors (corrosion fatigue, hydrogen), code-specified safety factors (ASME, API, EN 13445), and lifecycle vs operating cost trade-offs. Contact our engineering team for project-specific consultation.
| Property | Value | Unit | Condition |
|---|---|---|---|
| Density | 7.75 (0.280) | g/cm³ (lb/in³) | Aged, RT |
| Modulus of Elasticity (E) | 196 (28.5 × 10⁶) | GPa (psi) | RT |
| Shear Modulus (G) | 77 | GPa | RT |
| Poisson's Ratio | 0.27 | — | RT |
| Coefficient of Thermal Expansion | 10.8 / 11.6 / 12.2 | ×10⁻⁶ / °C | 20–100 / 20–315 / 20–540 °C |
| Thermal Conductivity | ~17.8 | W/m·K | RT |
| Specific Heat | 460 | J/kg·K | RT |
| Electrical Resistivity | 0.80 | μΩ·m | RT |
| Magnetic Permeability (μᵣ) | ~95 | — | Magnetic — martensitic matrix |
| Curie Temperature | ~480 | °C | |
| Melting Range | 1400–1440 | °C | Solidus / Liquidus |
17-4PH offers corrosion resistance roughly comparable to Type 304 in most environments — better than carbon and low-alloy steels, but inferior to Type 316L (which contains 2–3% Mo). The PREN of 17-4PH is approximately 17, well below the threshold for chloride pitting in seawater, which is why marine 17-4PH applications are typically limited to splash zones and short-term immersion rather than continuous full immersion.
The H-condition affects corrosion behavior. Lower-temperature aging (H900) produces highest strength but increases susceptibility to chloride stress-corrosion cracking (SCC) in high-chloride environments. Higher-temperature aging (H1100, H1150) reduces strength but significantly improves SCC resistance. For oil & gas service per NACE MR0175 / ISO 15156, 17-4PH is typically restricted to H1150-M double-aged condition with hardness ≤33 HRC.
For severe chloride or aggressive acid environments, consider upgrading to:
The following failure modes are the most commonly observed root causes in 17-4PH service failures we and customers have reviewed over the past decade. Knowing them lets you specify the right H-condition, NDE, and service envelope upfront — avoiding costly in-service recalls.
| Property | 17-4PH (H1025) | PH 13-8 Mo (H1000) | 15-5 PH (H1025) | 304L | 316L |
|---|---|---|---|---|---|
| UNS | S17400 | S13800 | S15500 | S30403 | S31603 |
| Type | Martensitic PH | Martensitic PH | Martensitic PH | Austenitic | Austenitic |
| UTS | ~1,070 MPa | ~1,520 MPa | ~1,070 MPa | ~515 MPa | ~485 MPa |
| YS (0.2%) | ~1,000 MPa | ~1,410 MPa | ~1,000 MPa | ~205 MPa | ~170 MPa |
| Density | 7.75 g/cm³ | 7.78 g/cm³ | 7.78 g/cm³ | 7.99 g/cm³ | 7.99 g/cm³ |
| Magnetic | Yes | Yes | Yes | No | No |
| PREN (approx) | 17 | 22 | 17 | 19 | 26 |
| Max service temp | ~315 °C | ~430 °C | ~315 °C | ~870 °C (low YS) | ~870 °C (low YS) |
| Transverse toughness | Moderate | Excellent (cleaner alloy) | Better than 17-4PH | Excellent | Excellent |
| Relative cost | 2 × | 4–5 × | 2.5 × | 1 × (baseline) | 1.3 × |
| Best use | General PH workhorse | Aerospace landing gear | Heavy aerospace forgings | General service | Marine / mild chloride |
17-4PH is one of the most weldable PH stainless steels. GTAW (TIG) and GMAW (MIG) are the most common processes; matching filler wire (per AMS 5825 / 5826) is preferred; ER630 is the generic equivalent. Welding should be performed in Condition A (solution annealed); after welding, perform a full solution treatment + age to recover properties in and around the weld zone. Preheating is generally not required for thin sections; thick or highly restrained joints may benefit from 150 °C preheat to reduce hydrogen-cracking risk.
Machinability of 17-4PH is approximately 50% of free-machining 416 stainless and somewhat better than 304/316L. Machining in Condition A (~33 HRC) is preferred — the alloy work-hardens less than austenitic grades. Use sharp, rigid carbide tooling, positive rake geometry, moderate cutting speeds (~50–80 m/min for turning), heavy positive feeds, and generous coolant. After final machining, age to the required H-condition. Aging dimensional change is typically <0.1% (slight contraction) but may matter for tight-tolerance parts.
17-4PH / UNS S17400 forges within a 1170–1230 °C window, with a finishing temperature above 950 °C to avoid the δ-ferrite range. Forging ratio should be ≥4:1 to break down the as-cast structure and meet AMS 5643 grain-flow requirements. The grade is well suited to all common forging routes — open-die forging for shafts and discs, hot ring rolling for seamless rings, closed-die forging for repeat-volume small parts, and upset forging for short, large-section blanks. Near-net-shape forging is practical on geometries where 30–50% of the rough machining can be eliminated by the die profile; this is typical for compressor impeller hubs and valve-body bodies. Slow furnace cooling after the final blow is essential — air or water quench from forging temperature can leave residual ferrite stringers visible on macroetch and may fail AMS 5643 micro-cleanliness checks. For long bored shafts above ~Ø 100 mm bore, ordering a trepanned billet rather than a solid bar reduces material input by 40–60% and shortens drilling time on the finished part.
17-4PH forging temperature range is 1170–1230 °C (2150–2250 °F). Do not forge below ~950 °C (~1750 °F) — the alloy work-hardens rapidly and cracking risk increases substantially. After forging, slow-cool (preferably furnace cool) to room temperature, then solution treat (1040 °C + air cool) and age to the desired H-condition. Heavy forgings may require intermediate stress-relief between forging operations.
As one of the most-requested grades in our portfolio, 17-4PH represents a high-volume production grade at Jiangyin Jiangnan Metal Co., Ltd. Our maximum forging envelopes for UNS S17400 reflect the alloy's good forgeability (better than most superalloys) and standard PH stainless heat-treatment cycles.
From raw material to finished MTC, every 17-4PH forging at Jiangyin Jiangnan Metal passes through these 8 controlled stages. Each step is logged on the heat-treatment chart and traceable on the final certificate.
The following equipment is qualified and calibrated for 17-4PH / UNS S17400 production. Section sizes and weights given are tested limits for this specific alloy (may differ from carbon steel limits).
Transparent delivery data, refreshed quarterly. Based on 387 17-4PH / UNS S17400 orders shipped Q1 2025 – Q1 2026.
% shown = orders shipped within the stated week count, measured from order confirmation to ex-works dispatch. For short-lead stock items (common bar sizes in Condition A), 4-6 week dispatch is possible — contact us for current stock.
For 17-4PH / UNS S17400 orders, the dominant specifications at Jiangyin Jiangnan Metal Co., Ltd. are the ASTM A564 / A693 / A705 family (general industrial / pressure vessel use) and AMS 5643 (aerospace bars and forgings). For European projects, DIN 1.4542 / EN 10088-3 applies. For oil & gas service, NACE MR0175 / ISO 15156 restrictions on hardness apply (typically requires H1150-M condition with hardness ≤33 HRC).
* NACE MR0175 / ISO 15156 sour-service compliance for 17-4PH typically requires the H1150-M double-aged condition with hardness ≤33 HRC. EN 10204 3.2 third-party witness certificates are issued through client-nominated inspection bodies (Lloyd's, DNV, BV, ABS, TÜV) on a per-order basis.
Each 17-4PH / UNS S17400 order passes through 6 mandatory hold points where production cannot proceed without QA sign-off: (1) raw material chemistry verification, (2) forging temperature compliance, (3) post-forging UT, (4) heat treatment chart approval, (5) mechanical test result acceptance, (6) final NDE + dimensional. Customer-witnessed hold points can be added on request at no charge.
Any out-of-specification finding triggers a formal NCR within 24 hours. Root-cause analysis (5-Why or Fishbone) completed within 5 working days. Customer receives the NCR with proposed disposition (rework / regrade / scrap / use-as-is with concession) before any action is taken. No silent rework.
Material found to be non-conforming within 6 months of delivery — verified by independent third-party test — is replaced free of charge, including freight. Shipping documentation is retained for 10 years to support warranty claims.
Customers retain unrestricted right to witness any production stage, including chemistry analysis, heat treatment cycles, mechanical testing, and final NDE. Witness travel arrangements coordinated with our QA team. For ASME / aerospace customers, dedicated quality liaison assigned.
17-4PH orders carry one decision that does not apply to most other stainless grades: which H-condition. The 7-step procedure below makes the choice explicit and minimizes ambiguity in the eventual MTC and supplied properties.
State the grade as UNS S17400 / ASTM A564 Type 630 (or AMS 5643 for aerospace, ASTM A705 Gr 630 for forgings, DIN 1.4542 for European projects). Avoid using "17-4 PH®" alone — it's a Cleveland-Cliffs trademark that implies their material.
Pick the aging condition matching your strength-vs-toughness need: H900 (highest strength) → H1025 (general purpose) → H1075 (pump shafts) → H1150 (best toughness) → H1150-M (NACE sour service). When in doubt, H1025 is the most common general-purpose choice.
Submit a 2D drawing or 3D model with all critical dimensions, tolerances, surface roughness, and grain-flow requirements.
State whether material should be supplied in Condition A (solution annealed only, for further fabrication) or in the final aged H-condition. Most finished parts are supplied aged.
Specify ultrasonic testing acceptance per ASTM A388, plus PT/MT requirements per ASTM E165 / E1417. For pressure-containing parts, specify ASME Section V acceptance criteria.
State whether EN 10204 3.1 (mill cert) or 3.2 (third-party witnessed) is required. For NACE service, specify NACE MR0175 / ISO 15156 compliance and required hardness limit.
Order quantity, target delivery date, and shipping destination. Standard 17-4PH lead time is 8–10 weeks; AMS-certified aerospace material 12–14 weeks.
Compiled from a decade of customer RFQs and post-delivery audits, these are the most frequent ordering errors that cause rework, lead-time delays, or in-service failures. Catching them at the spec stage costs nothing; catching them at receipt costs weeks.
The format below is the recommended engineering callout for 17-4PH forgings on any drawing — accepted by ASTM, AMS, EN, JIS, and GB practice. Copying this format into your CAD callouts eliminates 90% of ordering ambiguity.
Copy this template into your drawing's material callout box. Adjust H-condition, hardness, and NDE based on application — see the H-Condition Wizard for selection. For sour service, replace "H1025" with "H1150-M double-aged" and "33 HRC ± 2" with "≤33 HRC verified".
For pump shafts, valve bodies, marine hardware, or aerospace structural forgings in 17-4PH / UNS S17400, send us your specifications — including the required H-condition — and we'll respond within 24 hours with pricing, lead time, and confirmation of the applicable standards (ASTM A564 / A705 / AMS 5643 / DIN 1.4542). For complex inquiries, use the RFQ Generator above to produce a professional spec sheet.
The following are representative service environments where 17-4PH forgings are commonly specified. Project references and named case studies are available on request, subject to customer confidentiality agreements.
Approximate distribution of our 17-4PH / UNS S17400 forging shipments over the past 5 years, by end-user industry. Customer names protected under NDA.
Pump shafts & impellers — the largest single application of 17-4PH worldwide. H1025 or H1075 condition delivers high strength, good corrosion resistance, and excellent fatigue performance for centrifugal pumps in chemical, water, and marine service.
Oil & gas valves & wellhead components — typically H1150-M double-aged condition for NACE MR0175 compliance. Used in choke valves, valve bodies, valve trim, and sucker rod couplings.
Aerospace structural forgings — H1025 or H1150 condition per AMS 5643. Used in landing gear (where 13-8 Mo is not required), hydraulic actuator bodies, brackets, and accessory drive components.
Marine hardware — propeller shafts, rudder shafts, and deck hardware in splash-zone or short-immersion service. Continuous full-immersion seawater service requires upgrade to duplex or super-duplex.
Food & chemical processing equipment — agitator shafts, mixer paddles, and high-strength components in non-chloride environments. Higher strength enables thinner / lighter parts vs 304L equivalents.
Nuclear power components — control-rod drive mechanisms, primary-coolant pump shafts, and instrument-tube connections in reactor systems where moderate strength + corrosion resistance + ferromagnetic property are needed.
Each industry has dominant H-condition choices, certification requirements, and design pitfalls. These mini-guides distill what matters for the 5 highest-volume 17-4PH industries.
Dominant H-condition: H1075 for shafts (best fatigue + corrosion resistance balance), H1025 for impellers and casings (general strength + machinability), H1150 if chloride exposure is continuous.
Critical design factor: shaft critical speed must be ≤70% of operating speed. Use H1075 over H900 — endurance limit ratio 520/620 MPa, but H1075 is far less susceptible to chloride SCC over multi-year pump life.
Dominant H-condition: H1025 for bodies and stems (general industrial), H1150-M for any oil/gas (NACE), H900 only for non-corrosive high-pressure trim like seats.
Critical design factor: API 6A valve trim requires hardness ≤22 HRC for class HH/EE (sour), so H1150-M (24 HRC nominal) is the only legal 17-4PH condition for those classes. Body castings (where used) require ASME B16.34 pressure-temperature rating verification.
Dominant H-condition: H1025 for general structural (~155 ksi UTS, balance toughness + strength). H1150 only for components in high-fatigue regime needing maximum impact toughness. NEVER H900 for aerospace structural.
Critical design factor: AMS 5643 mandates transverse tensile tests + vacuum melting (VIM/VAR or AOD) + macroetch for grain flow verification. Charpy impact ≥27 J at RT. NDE per AMS-STD-2154 Class A ultrasonic. Source approval from prime aerospace OEM required.
Dominant H-condition: H1150-M double-aged — the ONLY 17-4PH condition compliant with NACE MR0175 / ISO 15156-3 for sour service. Hardness must be ≤33 HRC verified across the entire part.
Critical design factor: Hardness inspection at multiple locations including weld HAZ. API 6A class requires hardness map. For subsea / deepwater, also verify Charpy impact at the lowest service temperature. Avoid 17-4PH entirely for sour service above 175 °C — use Inconel 718 or 925 instead.
Dominant H-condition: H1150 for splash zone or short-immersion service. Avoid H900 and H925 — chloride SCC risk too high. For continuous full-seawater immersion, upgrade to 2205 duplex or super-duplex.
Critical design factor: PREN of 17-4PH ≈17, below the 32-35 threshold for chloride pit-free service in seawater. Limit chloride exposure to splash zone, intermittent submersion, or fresh-water-flushed environments. For class society (DNV, BV, LR, ABS, KR, CCS) approval, source-control via 3.2 cert.
Dominant H-condition: H1025 for general non-chloride food/chemical service, H1075 for fatigue-loaded agitator shafts, H1150 for any chloride-containing process fluid (cleaning solutions, brine).
Critical design factor: FDA / EHEDG / 3-A Sanitary compliance for food contact requires surface finish Ra ≤0.8 µm (typically electropolished). 17-4PH is hard to electropolish — coordinate with finisher early. For very acidic process (pH <3), upgrade to 904L or duplex.
The following are representative project scenarios. Specific project performance data and customer references are available under NDA on request.
Typical challenge: Chemical process pump shafts require high strength for shaft-stiffness limits (deflection control), good corrosion resistance for the process fluid, and excellent fatigue resistance under reversed bending and torsion.
Typical solution: Open-die forged UNS S17400 shaft, Ø 180 mm × 2.5 m long, supplied in H1075 aged condition (~1,000 MPa UTS / ~860 MPa YS). Solution at 1040 °C + air cool, then aged at 580 °C / 4 h / air cool. UT acceptance per ASTM A388 Class B; surface PT per ASTM E165.
Documentation: EN 10204 3.1 standard MTC; 3.2 with TÜV / BV witness available on request.
Wellhead valve body for sour-gas service requires NACE MR0175 / ISO 15156 compliance — limiting 17-4PH to the double-aged H1150-M condition with hardness ≤33 HRC. Forged block of UNS S17400, ~600 kg single-piece weight, double-aged per the standard cycle (760 °C / 2 h + 621 °C / 4 h), final hardness verified ≤33 HRC by Brinell. NACE compliance statement included on the MTC. Lead time 12–14 weeks including third-party witness on heat treatment.
Near-net-shape forging for an aircraft hydraulic actuator body, ~25 kg single-piece weight, supplied per AMS 5643 in H1025 condition. UT per AMS-STD-2154 Class A; PT per ASTM E1417 Type I, Method C, Form a-1, Sensitivity Level 3. Full chemistry, mechanical, and grain-flow verification on MTC. EN 10204 3.1 with optional aerospace OEM source-approval flow-down.
Trademark notice: 17-4 PH® is a registered trademark of Cleveland-Cliffs Inc. Material we produce is correctly described as UNS S17400 / ASTM A564 Type 630 / AMS 5643 / 1.4542. We are not affiliated with Cleveland-Cliffs Inc.
A single heat manufactured to EN 1.4542 limits will satisfy all other specifications simultaneously. We supply multi-designation MTC on request. See the Standards Variation section above for the full side-by-side comparison.
All chemistry, mechanical property, heat-treatment, and corrosion data on this page are sourced from published, peer-reviewed standards and engineering references listed below. Specific test results in our MTC are independent and traceable to NIST/NIM-calibrated equipment.
Standards referenced are the most current revisions known at the time of last page review. For procurement, always reference the revision number in force at the contract date. All trademark and copyright belong to their respective owners.