Nickel Alloy ENiMo-7-SR (Stress relieved)
Heat-treated state
UNS W80665
Low-temperature relief for distortion/residual-stress control only; must stay clear of the 550–800 °C ordering range that embrittles Ni-Mo weld metal.
Values for the SR condition
Other ENiMo-7 tempers and conditions
ENiMo-7 is listed in 3 conditions; see the grade overview at ENiMo-7.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Post-weld solution annealed 1065–1120 °C, rapid quench | Choose when the fabrication can be furnace-treated: dissolves interdendritic Mo-rich segregation and restores maximum HCl corrosion resistance and ductility. | 400 | 780 | 42 | 205 HB | 1.3 % IACS |
SRThis page Stress relieved | Low-temperature relief for distortion/residual-stress control only; must stay clear of the 550–800 °C ordering range that embrittles Ni-Mo weld metal. | 455 | 810 | 34 | 19 HRC | 1.3 % IACS |
AWDefault As-welded deposit | Standard condition for field repair and site welding of B-2 equipment where no post-weld heat treatment is possible. | 470 | 820 | 33 | 20 HRC | 1.3 % IACS |
What is ENiMo-7-SR?
ENiMo-7-SR is ENiMo-7 heat treated to SR — low-temperature relief for distortion/residual-stress control only; must stay clear of the 550–800 °C ordering range that embrittles Ni-Mo weld metal. ENiMo-7-SR has a yield strength of 455 MPa (66 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 67% of nickel alloy grades. Elongation at break is 34% and the elastic modulus is 217 GPa (31.5 Msi). ENiMo-7-SR has a density of 9.22 g/cm³ (0.333 lb/in³), heavier than 97% of nickel alloy grades. It melts at 1,330°C (2,426 °F). AW is the default condition FabDigit quotes; SR is available on request or by drawing note.
Limitations
- Limited service temperature — 425°C (797 °F), worse than 90% of nickel alloy grades
ENiMo-7-SR properties
Typical room-temperature values for ENiMo-7-SR; 23 are specific to this condition. Other listed values are ENiMo-7 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
ENiMo-7-SR has a density of 9.22 g/cm³ (0.333 lb/in³), heavier than 97% of nickel alloy grades. It melts at 1,330°C (2,426 °F).
Mechanical17
ENiMo-7-SR has a yield strength of 455 MPa (66 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 67% of nickel alloy grades. Elongation at break is 34% and the elastic modulus is 217 GPa (31.5 Msi).
Thermal5
ENiMo-7-SR is rated for continuous service to 425°C (797 °F). It conducts heat at 11.2 W/m·K (6.47 BTU/hr·ft·°F), worse than 52% of nickel alloy grades. Thermal expansion is 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
ENiMo-7-SR conducts electricity at 1.3 % IACS, worse than 95% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (80/100), better than 61% of nickel alloy grades.
Sustainability4
Producing a kilogram of ENiMo-7-SR takes about 175 MJ of energy and emits 13.5 kg of CO₂ — more than 65% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability6
ENiMo-7-SR's machinability is poor (20/100, better than 53% of nickel alloy grades); weldability very good (70/100); formability fair (48/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ENiMo-7-SR
Is ENiMo-7 easy to machine?
Weld metal work-hardens severely — use sharp carbide, heavy positive rake, slow speed with high feed and flood coolant; grind rather than machine where possible.
Can ENiMo-7 be welded?
DCEP, stringer beads, low heat input (<1.5 kJ/mm), interpass below 100–120 °C, electrodes rebaked at ~250–300 °C to avoid porosity; keep joints free of iron and copper contamination.
Can ENiMo-7 be formed, bent or molded?
Not a forming product; deposit is ductile enough for light peening/dressing but avoid heavy cold work before service in acid.
What surface finishes work on ENiMo-7?
Grind flush and pickle/passivate lightly or mechanically clean to remove slag, oxide and any embedded iron before commissioning in HCl service.
ENiMo-7 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 |
|---|---|---|
| Mo | 26 – 30 | 28 |
| Fe | ≤ 2 | 1 |
| Cr | ≤ 1 | 0.5 |
| Co | ≤ 1 | — |
| W | ≤ 1 | — |
| Mn | ≤ 1.75 | 0.8 |
| Si | ≤ 0.2 | 0.08 |
| C | ≤ 0.02 | 0.01 |
| Cu | ≤ 0.5 | — |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Other, total | ≤ 0.5 | — |
| Niremainder, typically ~68–70 % | balance | — |
ENiMo-7-SR — frequently asked
What is ENiMo-7-SR used for?
ENiMo-7-SR is typically used for field repair of HCl service vessels, manual welding of Ni-Mo alloy (B-2 type) components, weld overlay on steel for reducing-acid duty, repair of nickel alloy pump and valve castings, on-site pipe spool welds in acid plants and patch welds on reactors and digesters. In short: manual electrode for B-2; reducing-acid weld metal; field-repair Ni-Mo filler.
What is the yield strength of ENiMo-7-SR?
ENiMo-7-SR has a typical yield strength of 455 MPa (66 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 67% of nickel alloy grades. Strength varies by condition: see the 3 listed tempers.
Is ENiMo-7-SR easy to machine?
Not especially — machinability is rated poor (20/100, better than 53% of nickel alloy grades). Weld metal work-hardens severely — use sharp carbide, heavy positive rake, slow speed with high feed and flood coolant; grind rather than machine where possible.
Can ENiMo-7-SR be welded?
Yes — weldability is rated very good (70/100). DCEP, stringer beads, low heat input (<1.5 kJ/mm), interpass below 100–120 °C, electrodes rebaked at ~250–300 °C to avoid porosity; keep joints free of iron and copper contamination.
What surface finishes work on ENiMo-7-SR?
Grind flush and pickle/passivate lightly or mechanically clean to remove slag, oxide and any embedded iron before commissioning in HCl service.
Can ENiMo-7-SR be formed, bent or molded?
Not a forming product; deposit is ductile enough for light peening/dressing but avoid heavy cold work before service in acid.
What is the maximum service temperature of ENiMo-7-SR?
ENiMo-7-SR is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ENiMo-7-AW and ENiMo-7-SA?
AW is the default condition — standard condition for field repair and site welding of B-2 equipment where no post-weld heat treatment is possible. SA: choose when the fabrication can be furnace-treated: dissolves interdendritic Mo-rich segregation and restores maximum HCl corrosion resistance and ductility. Yield strength is 470 MPa in AW versus 400 MPa in SA.
Sources
- AWS A5.11/A5.11M — Nickel and Nickel-Alloy Welding Electrodes for Shielded Metal Arc Welding — American Welding Society (2018)
- ASTM B333 / UNS N10665 (alloy B-2) plate and sheet — ASTM International (2018)
- Nickel-molybdenum alloy B-2 physical and corrosion data — Haynes International / Special Metals (2020)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (Ni alloys) — ASM International (1993)
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.