Stainless Steel ER630-H900
Precip hard
UNS S17400
H900 = 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.
Values for the H900 condition
Other ER630 tempers and conditions
ER630 is listed in 9 conditions; see the grade overview at ER630.
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 |
H900This page 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-H900?
ER630-H900 is ER630 in the H900 condition — maximum strength and hardness for the weld metal; lowest toughness and highest SCC/hydrogen sensitivity. ER630-H900 has a yield strength of 1,170 MPa (170 ksi) and a tensile strength of 1,310 MPa (190 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 10% and the elastic modulus is 197 GPa (28.6 Msi). ER630-H900 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). AW is the default condition FabDigit quotes; H900 is available on request or by drawing note.
Advantages
- High strength — 1,170 MPa (170 ksi), better than 98% of stainless steel grades
Limitations
- Limited ductility — 10%, worse than 98% of stainless steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 91% 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
- Needs corrosion protection — 50/100, worse than 78% of stainless steel grades
ER630-H900 properties
Typical room-temperature values for ER630-H900; 13 are specific to this condition. Other listed values are ER630 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER630-H900 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-H900 has a yield strength of 1,170 MPa (170 ksi) and a tensile strength of 1,310 MPa (190 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 10% and the elastic modulus is 197 GPa (28.6 Msi).
Thermal6
ER630-H900 is rated for continuous service to 300°C (572 °F). It conducts heat at 17.9 W/m·K (10.3 BTU/hr·ft·°F), better than 73% of stainless steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
ER630-H900 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-H900 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-H900's machinability is fair (35/100, better than 51% of stainless steel grades); weldability very good (75/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER630-H900
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.
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.
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 | — |
ER630-H900 — frequently asked
What is ER630-H900 used for?
ER630-H900 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-H900?
ER630-H900 has a typical yield strength of 1,170 MPa (170 ksi) and a tensile strength of 1,310 MPa (190 ksi) — stronger than 98% of stainless steel grades. Strength varies by condition: see the 9 listed tempers.
Is ER630-H900 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-H900 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-H900?
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-H900 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-H900?
ER630-H900 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.