Stainless Steel ER630
UNS S17400
ER630 (S17400) is a precipitation-hardening martensitic stainless bare wire matched to 17-4PH, strengthened by copper precipitation during aging.
Reference datasheet — ER630 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the AW condition
ER630 tempers and conditions
ER630 is supplied in 9 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Double overaged 760 °C + 621 °C | Lowest-strength, highest-toughness weld condition for cryogenic or severe SCC service. | 515 | 790 | 19 | 24 HRC | 1.6 % IACS |
Overaged 621 °C (1150 °F) for 4 h, maximum toughness | Toughest standard age; preferred for sour/chloride service and NACE-type limits (≤33 HRC). | 725 | 930 | 16 | 31 HRC | 22 W/m·K |
AWDefault As-welded deposit | Default condition when PWHT is impossible; gives moderate-high strength low-carbon martensite with limited ductility. | 760 | 965 | 12 | 33 HRC | 1.9 % IACS |
Solution annealed | Post-weld solution treatment to homogenise the weld before ageing; not a final service condition. | 760 | 1,030 | 12 | 33 HRC | 2.2 % IACS |
Aged 593 °C (1100 °F) for 4 h | Overaged condition trading strength for toughness and stress-corrosion resistance. | 795 | 965 | 15 | 33 HRC | 1.6 % IACS |
Aged 579 °C (1075 °F) for 4 h | Good ductility with ~1000 MPa strength; frequent choice for welded pressure parts. | 860 | 1,000 | 14 | 36 HRC | 1.6 % IACS |
Aged 552 °C (1025 °F) for 4 h | Balanced strength/toughness; common for pump shafts and valve components. | 1,000 | 1,070 | 13 | 38 HRC | 1.7 % IACS |
Aged 496 °C (925 °F) for 4 h | Near-peak strength with slightly better toughness and SCC resistance than H900. | 1,070 | 1,170 | 11 | 42 HRC | 1.8 % IACS |
Aged 482 °C (900 °F) for 1 h, peak hardness | Maximum strength and hardness for the weld metal; lowest toughness and highest SCC/hydrogen sensitivity. | 1,170 | 1,310 | 10 | 44 HRC | 18 W/m·K |
What is ER630?
ER630 (S17400) is a precipitation-hardening martensitic stainless bare wire matched to 17-4PH, strengthened by copper precipitation during aging. It is used for structural welds and repair on 17-4PH parts and can be heat treated through Condition A and the H900 to H1150M range; typical deposit values are 760 MPa yield, 965 MPa tensile, 12% elongation and 33 HRC. Corrosion resistance (score 50) is well below duplex and austenitic fillers, service is limited to about 300 °C, and full properties require post-weld solution treatment plus aging. ER630 has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 57% of stainless steel grades. It melts at 1,404°C (2,559 °F). ER630 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 965 MPa (140 ksi) — stronger than 94% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 197 GPa (28.6 Msi).
What is ER630 used for?
- 17-4PH structural components
- Pump shafts and valve stems
- Aerospace hardware repair
Advantages
- High strength — 760 MPa (110 ksi), better than 94% of stainless steel grades
Limitations
- Limited ductility — 12%, worse than 95% of stainless steel grades
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- Low electrical conductivity — 1.9 % IACS, worse than 84% of stainless steel grades
- Low fracture toughness — 78 MPa·√m (71 ksi·√in), worse than 81% of stainless steel grades
- Needs corrosion protection — 50/100, worse than 78% of stainless steel grades
ER630 properties
Typical room-temperature values for ER630-AW; bars are the position among stainless steel grades.
Physical3
ER630 has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 57% of stainless steel grades. It melts at 1,404°C (2,559 °F).
Mechanical16
ER630 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 965 MPa (140 ksi) — stronger than 94% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 197 GPa (28.6 Msi).
Thermal6
ER630 is rated for continuous service to 300°C (572 °F). It conducts heat at 17.5 W/m·K (10.1 BTU/hr·ft·°F), better than 72% of stainless steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
ER630 conducts electricity at 1.9 % IACS, worse than 84% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of ER630 takes about 53 MJ of energy and emits 5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 50%.
Manufacturability7
ER630's machinability is fair (35/100, better than 51% of stainless steel grades); weldability very good (75/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. ER630 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ER630
Is ER630 easy to machine?
Machine weld metal in Condition A or H1150; carbide tooling, rigid setups and positive rake — hardness above 40 HRC after H900 makes finishing best done by grinding.
Can ER630 be welded?
GTAW/GMAW with Ar or Ar+2% CO₂; preheat 100–150 °C for thick sections, interpass ≤150 °C, low heat input, and PWHT (solution + age) whenever full mechanical properties are required.
Can ER630 be formed, bent or molded?
Not a wrought product form; deposited martensitic weld metal has little cold formability — shape by machining rather than bending.
ER630 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | ≤ 0.05 | 0.03 |
| Cr | 16 – 16.75 | 16.4 |
| Ni | 4.5 – 5 | 4.7 |
| Cuprecipitation hardener | 3.25 – 4 | 3.6 |
| NbNb+Ta | 0.15 – 0.3 | 0.22 |
| Mn | 0.25 – 0.75 | 0.5 |
| Si | ≤ 0.75 | 0.5 |
| Mo | ≤ 0.75 | 0.2 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance |
What surface finishes work on ER630?
Passivate (ASTM A967 citric/nitric) or electropolish after removing weld scale; polishes well, and hard chrome or nitriding can be used where wear resistance is needed.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel ER630 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S17400
How much does ER630 cost?
ER630 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
ER630 — frequently asked
What is ER630 used for?
ER630 is typically used for 17-4PH structural components, pump shafts and valve stems and aerospace hardware repair. In short: only PH stainless filler; age-hardenable weld metal; highest strength stainless filler.
What is the yield strength of ER630?
ER630 has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 965 MPa (140 ksi) — stronger than 94% of stainless steel grades. Strength varies by condition: see the 9 listed tempers.
Is ER630 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Machine weld metal in Condition A or H1150; carbide tooling, rigid setups and positive rake — hardness above 40 HRC after H900 makes finishing best done by grinding.
Can ER630 be welded?
Yes — weldability is rated very good (75/100). GTAW/GMAW with Ar or Ar+2% CO₂; preheat 100–150 °C for thick sections, interpass ≤150 °C, low heat input, and PWHT (solution + age) whenever full mechanical properties are required.
What surface finishes work on ER630?
Passivate (ASTM A967 citric/nitric) or electropolish after removing weld scale; polishes well, and hard chrome or nitriding can be used where wear resistance is needed.
Can ER630 be formed, bent or molded?
Not a wrought product form; deposited martensitic weld metal has little cold formability — shape by machining rather than bending.
What is the maximum service temperature of ER630?
ER630 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER630-AW and ER630-H900?
AW is the default condition — default condition when PWHT is impossible; gives moderate-high strength low-carbon martensite with limited ductility. H900: maximum strength and hardness for the weld metal; lowest toughness and highest SCC/hydrogen sensitivity. Yield strength is 760 MPa in AW versus 1,170 MPa in H900.
How much does ER630 cost?
ER630 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- AWS A5.9/A5.9M Bare Stainless Steel Welding Electrodes and Rods (ER630) — AWS (2017)
- ASTM A564/A693 (17-4PH, UNS S17400) — heat treatment conditions H900–H1150M — ASTM (2019)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- 17-4PH Stainless Steel Product Data Bulletin — AK Steel / Cleveland-Cliffs (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.