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17-4PH Stainless Steel Forgings (UNS S17400 / AISI 630) — Manufacturer & Supplier | Jiangsu Liangyi

⚡ 17-4PH (UNS S17400) Quick Reference

17-4PH stainless steel, also known as UNS S17400, AISI 630, SUS 630, Grade 630, or EN 1.4542, is a martensitic precipitation hardening stainless steel that contains about 17% chromium (Cr), 4% nickel (Ni), and 4% copper (Cu). It has tensile strengths ranging from 795 MPa (H1150M) to over 1310 MPa (H900) by strictly age-hardening heat treatment, it also has great corrosion resistance which makes it the best choice of forging material for oil & gas, power generation, marine, and aerospace industrials. Jiangsu Liangyi can supply all standard heat treatment products as per ASTM A564 / A705 and is also API 6A 105K sour service certified.

20+
Years Forging Experience
50+
Countries & Regions Served
500+
Global Industrial Customers
API 6A
Certified Manufacturer
ISO
Quality Management Certified

17-4PH (UNS S17400/AISI 630) Forgings — Manufacturer Introduction

Jiangsu Liangyi is a professional custom 17-4PH forging manufacturer, specializing in producing stainless steel forgings, open die forgings, and seamless rolled forged rings in this alloy (UNS S17400 / AISI 630 / SUS 630 / EN 1.4542). All products meet the strict production standards of ASTM A564/A705.

As a leading Chinese forging manufacturer, we can supply a full range of 17-4PH forged components at any standard heat treatment conditions: H900, H925, H1025, H1075, H1100, H1150, H1150M, and H1150D.

17-4PH forged components are the best material choice for high-demand industrial fields. Through air-melted, ESR (Electroslag Remelting), and VAR (Vacuum Arc Remelting) melting processes, all our refined materials achieve perfect cleanliness, fewer inclusions, and no alloy segregation — making our forgings suitable for oil & gas, power generation, chemical, marine, and other critical industries.

17-4PH stainless steel forgings (UNS S17400/AISI 630) by Jiangsu Liangyi — forged bars, seamless rolled rings, and custom open-die forgings
Jiangsu Liangyi 17-4PH stainless steel forgings — forged bars, seamless rolled rings, and custom open-die forgings for global industries.

17-4PH Forged Steel Product Range

We offer a full range of custom forgings in this grade with different shapes and specifications as per all global clients' needs. Following is our full forging products catalog for specifications and dimensions.

17-4PH Forgings — Industry Applications

Our 17-4PH forged products can work well in the strict industrial environments. Below are delivered products that showcase our capabilities as a specialized forging manufacturer.

Oil & Gas Industry — 17-4PH Forgings

The oil and gas have strict requirement of forging material choose, particularly in harsh downhole and subsea environments. Our 17-4PH forgings and API 6A 105K bars are the top choice:

Case 1 — Saudi Arabia Oilfield Sour Service Project: We supplied 500+ pieces of API 6A 105K forged bars in UNS S17400 (H1150D condition) to a big Saudi Arabian oilfield company. The products were used in wellhead equipment with H2S content ≥15% and 15,000 psi. They were API 6A certified, NACE MR0175 tested. All finished work very well with no failures after two years of use. Our production time was only 45 days.

Power Generation Industry — 17-4PH Turbine Impeller Forgings

Gas & steam turbines and nuclear power plants need forgings that can withstand high-temperatures and stay stable for a long time. Our turbine forgings in this alloy (H1150M condition) are widely used:

Case 2 — Germany 800 MW Power Generation Project: We supplied turbine impeller forgings (H1150M, 850 kg, ⌀1200 mm) for an 800 MW German power company as per ASTM A705 Type 630. VAR-refined material get impact resistance >80 J. Met German DIN requirements and full European traceability standards.

Valve Industry — 17-4PH Fluid Control Component Forgings

Forgings for valves and fluid systems need to be very hard, seal well and resist corrosion. We make all kinds of valve parts in this grade:

Case 3 — North American Chemical Plant Valve Project: We supplied 300+ sets of valve forgings in this alloy (balls, stems, bonnets, H900 condition) to a U.S. chemical company. Hardness >40 HRC. Excellent resistance to sulfuric acid and chlorine gas corrosion. Certified to ASTM A564, supplied with EN10204-3.1 certificates.

Marine & Heavy Machinery — 17-4PH Forgings

Marine and heavy machinery need forgings that can withstand saltwater corrosion and have long lifetime:

Case 4 — About Singapore Marine Propulsion Project: We made forged propeller shafts in 17-4PH (⌀350 mm × 6000 mm, H1075 condition, tensile strength >1000 MPa) and seamless rolled rings (SUS 630) for a Singapore shipyard.There parts were 100% UT and MPE tested.And already working well in saltwater marine environment without failure.

17-4PH API 6A 105K sour service forged bars (H1150D condition) for oil and gas wellhead equipment — NACE MR0175 compliant, manufactured by Jiangsu Liangyi
17-4PH API 6A 105K sour service forged bars (H1150D condition) — for oilfield wellhead equipment, according to NACE MR0175.

17-4PH (UNS S17400) Chemical Composition — Per ASTM A564

The chemical composition is a key factor in how well the alloy performs. All our forgings comply with ASTM A564/A564M (Standard Specification for Hot-Rolled and Cold-Finished Age-Hardening Stainless Steel Bars and Shapes). See Table 1 below:

Table 1: 17-4PH (UNS S17400 / AISI 630) Chemical Composition per ASTM A564
Chemical Element Content (Max / Range) % Chemical Element Content (Max / Range) %
Carbon (C)0.07% maxMolybdenum (Mo)
Chromium (Cr)15.00–17.50%Phosphorus (P)0.040% max
Manganese (Mn)1.00% maxNiobium + Tantalum (Nb+Ta)0.15–0.45%
Nickel (Ni)3.00–5.00%Sulfur (S)0.030% max
Silicon (Si)1.00% maxCopper (Cu)3.00–5.00%
Iron (Fe)Balance

For power-plant turbine impeller forgings, we offer a modified composition per ASTM A705 Type 630: Cr 15.0–17.5%, Ni 3.0–5.0%, Cu 3.0–5.0%, Nb+Ta 0.15–0.45%, which further improves high-temperature performance.

Note on naming: This alloy is also designated EN 1.4542 (European standard) and SUS 630 (Japanese JIS standard). All these names — 17-4PH, UNS S17400, AISI 630, EN 1.4542, SUS 630 — refer to the same precipitation hardening stainless steel with identical chemical composition and mechanical properties.

17-4PH Forging Process and Heat Treatment

Correct heat treatment and forging processes are the main reasons we can supply stable, high-quality forgings in this grade. We follow advanced forging and heat treatment technology to ensure the excellent, consistent performance of every batch.

Key Forging Temperatures for 17-4PH

Standard Precipitation Hardening Conditions — 17-4PH Mechanical Properties (ASTM A564)

All conditions below are per ASTM A564/A564M:

Table 2: 17-4PH Mechanical Properties per Heat Treatment Condition (ASTM A564)
Condition Aging Temp. °F (°C) Tensile (Rm) MPa Yield 0.2% (Rp0.2) MPa Elongation % RA % Hardness HB / HRC Impact KV (21°C) J
H900900°F (482°C)≥1310≥1170≥10≥40≥388 / ≥40
H925925°F (496°C)≥1170≥1070≥10≥44≥375 / ≥38≥6.8
H10251025°F (552°C)≥1070≥1000≥12≥45≥331 / ≥35≥20
H10751075°F (579°C)≥1000≥860≥13≥45≥311 / ≥32≥27
H11001100°F (593°C)≥965≥795≥14≥45≥302 / ≥31≥34
H11501150°F (621°C)≥930≥725≥16≥50≥277 / ≥28≥41
H1150M1400°F + 1150°F≥795≥520≥18≥55≥255 / ≥24≥75
H1150D1150°F × 2 cycles≥860≥725≥16≥50≥255 / ≥24≥41

Custom H1150M Heat Treatment — 17-4PH Turbine Impeller Forgings

For turbine impeller forgings with special performance requirements, we offer custom H1150M heat treatment way in following:

17-4PH API 6A 105K Sour Service Forgings

Forgings to API Specification 6A 105K sour standard must meet the highest technical requirements for heat treatment and mechanical properties. As an API-certified manufacturer, we strictly follow API 6A 105K when producing sour service components according to NACE MR0175 / ISO 15156.

Heat Treatment — H1150D Method A (API 6A 105K Sour Service)

Charpy V-Notch Impact Requirements — API 6A 105K (ASTM A370)

Table 3: Charpy V-Notch Impact Requirements for 17-4PH API 6A 105K Sour Service Bars (ASTM A370)
Temperature Class Test Temperature Min Average Impact Value Min Individual Value
L−50°F (−46°C)27 J (20 ft-lbf)18 J (13 ft-lbf)
P−20°F (−29°C)41 J (30 ft-lbf)27 J (20 ft-lbf)

Acceptance: Each individual specimen must be ≥2/3 of the specified average value. For batches with only 2 specimens, each specimen must individually meet or exceed the minimum average specified in API 6A 105K.

Ultrasonic testing (UT per ASTM A388) of 17-4PH UNS S17400 forged bars at Jiangsu Liangyi quality control laboratory — 100% NDE inspection for API 6A 105K sour service forgings
100% Ultrasonic Testing (UT per ASTM A388) of 17-4PH forgings at Jiangsu Liangyi — mandatory for all API 6A 105K sour service products.

17-4PH Forgings — Quality Control & NDE Inspection

We follow ASTM, API and ASME international standards for 100% quality control and full non-destructive examination (NDE) . No flaws allowed in 17-4PH forgings like porosity, internal bursts, flakes, laps, seams or cracks.

  1. Visual Inspection (VT): Check for laps, cold shuts, and all other surface flaws on 100% full-surface according to AWS standards.
  2. Ultrasonic Testing (UT): According to ASTM A388/388M. all forged parts must pass 100% UT after heat treatment and before machining
  3. Magnetic Particle Examination (MPE): All products were checked for cracks on the surface and just below the surface according to ASTM A275/275M.
  4. Mechanical Testing: 100% batch testing for tension test (ASTM E8), hardness (HB/HRC), and Charpy V-notch impact test
  5. Chemical Analysis: All materials tested per ASTM A751; certified chemical report is issued per heat/serial number.

Certification & Full Traceability

We issue official EN 10204-3.1 material certificates for all 17-4PH forgings that show where the raw material comes from and how it was made. Each certificate includes:

17-4PH vs Other Stainless Steel Grades — Forging Material Comparison

When selecting forging material for demanding industrial applications, understanding how 17-4PH (UNS S17400) compares against other stainless steels is essential. Also see our full stainless steel forging materials guide.

Table 4: 17-4PH (UNS S17400) vs Other Common Stainless Steel Forging Grades
Property 17-4PH H900 (S17400) 316L SS (S31603) 17-7PH CH900 (S17700) 15-5PH H900 (S15500)
Steel TypeMartensitic PHAusteniticSemi-Austenitic PHMartensitic PH
Tensile Strength≥1310 MPa~515 MPa≥1380 MPa≥1310 MPa
Yield Strength (0.2%)≥1170 MPa~205 MPa≥1170 MPa≥1170 MPa
Hardness (HRC)≥40~90 HRB≥41≥38
Corrosion ResistanceGoodExcellentGoodGood
MagneticYesNoYesYes
NACE MR0175 Sour Service✓ Yes (H1150D)Limited✗ No✓ Yes
WeldabilityGoodExcellentModerateGood
EN Designation1.45421.44041.4568
Best ApplicationsOil & Gas, Marine, ValvesFood, Pharma, ChemicalAerospace, SpringsOil & Gas, Aerospace

Why Choose Jiangsu Liangyi as Your 17-4PH Forgings Manufacturer

We are one of China's top 17-4PH forging manufacturers and global suppliers, our main strengths are:

Technical Glossary — 17-4PH Stainless Steel Forging Terms

Precipitation Hardening (PH)
A heat treatment process that strengthens alloys by forming fine precipitates (copper-rich phases in 17-4PH) within the metal matrix during controlled aging at moderate temperatures (482–760°C). This dramatically increases yield strength and hardness compared to the solution-annealed condition.
ESR — Electroslag Remelting
We will do a secondary metallurgical refining process so the alloy is remelted through a molten slag layer, thus non-metallic inclusions removed and cleanliness, homogeneity, and mechanical properties of 17-4PH (UNS S17400) billets improved.
VAR — Vacuum Arc Remelting
A remelting process performed under vacuum, eliminating dissolved gases and volatile trace elements from the melt. VAR-refined 17-4PH have the highest purity and is widely used for critical aerospace, nuclear, and high-reliability oil & gas industrials.
NACE MR0175 / ISO 15156
An international standard (published by NACE International / AMPP) specifying material requirements for metallic equipment in oil and gas environments containing hydrogen sulfide (H2S) — called "sour service." 17-4PH in H1150D condition according to this standard for acceptable use.
API 6A 105K
API Specification 6A is in charge of the equipment used in wellhead and christmas tree. The "105K" material class says that the minimum yield strength must be 105,000 psi (725 MPa). This,along with sour service requirements, makes up the most strict oilfield forging specification for 17-4PH.
Open Die Forging
A forging process where the workpiece is shaped by flat or simple-contour dies that do not enclose the material completely, makes the production of large, custom-shaped billets, bars, discs, and rings in 17-4PH stainless steel possible.
EN 10204-3.1 Material Certificate
The manufacturer's authorized inspectors will issue a material test certificate according to European standard (Type 3.1) , it says the actual chemical composition and mechanical test results for each specific heat/lot of forging material supplied. Required by most global industrial buyers.
Charpy V-Notch (CVN) Impact Test
A standardized test per ASTM A370 measures the energy absorbed by a notched specimen during fracture at a specified temperature. For API 6A 105K 17-4PH sour service forgings: minimum 27 J at −46°C (Class L) or 41 J at −29°C (Class P).
UNS — Unified Numbering System
A standardized alloy name system used in North America (ASTM/SAE). UNS S17400 is the official designation for 17-4PH precipitation hardening stainless steel — equivalent to AISI 630, EN 1.4542, and SUS 630.

Frequently Asked Questions — 17-4PH Stainless Steel Forgings

What is 17-4PH stainless steel (UNS S17400)?

17-4PH (UNS S17400 / AISI 630 / EN 1.4542) is a martensitic precipitation hardening stainless steel containing approximately 17% chromium, 4% nickel, and 4% copper. It achieves tensile strengths up to ≥1310 MPa (H900 condition) through age-hardening heat treatment, combined with good corrosion resistance and moderate toughness — widely used in oil & gas, aerospace, marine, power generation, and valve industries.

What is the difference between 17-4PH H900 and H1150D heat treatment conditions?

H900 (aged at 482°C/900°F) delivers maximum strength: tensile strength ≥1310 MPa and hardness ≥40 HRC, making it ideal for valve components and pump parts requiring high hardness. H1150D (double aging at 621°C/1150°F × 2 cycles) offers lower strength (≥860 MPa) but much higher toughness (≥41 J impact at 21°C) and meets NACE MR0175 requirements — the correct condition for API 6A 105K sour service oilfield equipment exposed to H2S.

What is API 6A 105K 17-4PH sour service forging?

API 6A 105K 17-4PH sour service forgings are stainless steel forgings which meet API Specification 6A used for wellhead and Christmas tree equipment with 105,000 psi (725 MPa) minimum yield strength, produced via H1150D double-aging heat treatment and compliant with NACE MR0175/ISO 15156 for H2S environments. Required Charpy V-notch impact: ≥27 J at −46°C (Class L) or ≥41 J at −29°C (Class P) per ASTM A370.

What industries use 17-4PH stainless steel forgings?

17-4PH stainless steel forgings are mainly used in: (1) Oil & Gas — downhole drilling tools, wellhead equipment, subsea X-tree parts, BOP components; (2) Power Generation — turbine impellers, pump casings, nuclear coolant pump rotors; (3) Valve production — valve balls, stems, bonnets, seat rings; (4) Marine & Offshore — propeller shafts, rudder shafts, marine valves; (5) Chemical Processing — corrosion-resistant fluid control; (6) Aerospace and defense — high strength-to-weight applications.

What is the chemical composition of 17-4PH (UNS S17400) per ASTM A564?

As per ASTM A564, 17-4PH (UNS S17400) chemical composition is: Chromium (Cr) 15.00–17.50%, Nickel (Ni) 3.00–5.00%, Copper (Cu) 3.00–5.00%, Niobium+Tantalum (Nb+Ta) 0.15–0.45%, Carbon (C) max 0.07%, Manganese (Mn) max 1.00%, Silicon (Si) max 1.00%, Phosphorus (P) max 0.040%, Sulfur (S) max 0.030%, Iron (Fe) balance.

Is 17-4PH stainless steel magnetic?

Yes. 17-4PH (UNS S17400) is ferromagnetic in both solution annealed (Condition A) and all aged conditions (H900–H1150D) due to its martensitic microstructure. This distinguishes it from non-magnetic austenitic stainless steels such as 316L (UNS S31603). Its magnetic nature is important to consider for applications near magnetically sensitive instruments or in electromagnetic compatibility-sensitive environments.

What is the difference between ESR and VAR refined 17-4PH?

ESR (Electroslag Remelting) refines 17-4PH by passing it through a molten slag layer, significantly reducing non-metallic inclusions and improving cleanliness — suitable for most industrial and oilfield applications. VAR (Vacuum Arc Remelting) is a higher-purity process performed under vacuum, eliminating dissolved gases and volatile impurities to achieve superior homogeneity. VAR-refined 17-4PH is specified for critical aerospace, nuclear power, and highest-performance oil & gas applications where maximum fatigue life and reliability are required.

What NDE inspections does Jiangsu Liangyi perform on 17-4PH forgings?

Jiangsu Liangyi performs 100% inspection including: Visual Inspection (VT) for surface defects; Ultrasonic Testing (UT per ASTM A388) for internal flaws; Magnetic Particle Examination (MPE per ASTM A275) for surface/near-surface cracks; Mechanical Testing (tension per ASTM E8, hardness HB/HRC, Charpy V-notch impact); and Chemical Analysis (per ASTM A751). All products are supplied with EN10204-3.1 material test certificates and full traceability records.

What is the lead time for custom 17-4PH forgings from Jiangsu Liangyi?

Normal lead time for custom 17-4PH forgings is 30–60 days depending on client's drawing, quantity, and heat treatment condition required. For API 6A 105K sour service forgings (H1150D), typical lead time is within 45 days. Rush orders are available per client requirements. Free quotes are provided within 24 hours after inquiry.

What certifications does Jiangsu Liangyi hold for 17-4PH forgings?

Jiangsu Liangyi is an API 6A certified manufacturer for 105K sour service forgings and operates under the ISO 9001 quality management system. All 17-4PH forgings are shipped with EN 10204-3.1 material certificates. Products comply with ASTM A564/A705, API 6A, ASME codes, and NACE MR0175/ISO 15156 for sour service materials. Full chemical, mechanical, and NDE test reports are provided for each order.

17-4PH Forgings Inquiry — Contact Jiangsu Liangyi

Just get in touch with us if you need custom 17-4PH forgings or a free quote for your forging project,Our professional sales and technical team will get back to you within 24 hours with the best custom solution!

If you have any questions about 17-4PH forgings, UNS S17400 / AISI 630 forged parts, API 6A 105K bars or other custom forged parts for oil & gas, power generation, marine or valve industries — our team is ready to help you with professional technical solutions and full after-sales support.

Jiangsu Liangyi is a world-leading manufacturer of 17-4PH (UNS S17400 / AISI 630) forged stainless steel components, API 6A 105K bars, turbine impeller forgings, and valve forgings. We offer competitive prices, fast lead times, and fully customized solutions for oil & gas, power generation, nuclear power, marine, valve, and heavy equipment in over 50 countries.

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