Stainless Steel E308Mo
UNS W30820 · ASTM A5.4
E308Mo is a standard-carbon, 308-type austenitic stainless covered electrode to AWS A5.4 (UNS W30820) with a molybdenum addition that raises pitting resistance above plain E308.
Reference datasheet — E308Mo 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
E308Mo tempers and conditions
E308Mo is supplied in 5 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution Annealed (~1050 °C, water quenched) deposit | Use when the weldment is solution annealed after welding (e.g. clad or overlay parts) to dissolve carbides and restore full intergranular corrosion resistance; strength drops and ferrite is largely retained but redistributed. | 300 | 550 | 45 | 160 HB | 2.4 % IACS |
AWDefault As-welded deposit | Default condition for all austenitic stainless SMAW deposits; use for normal fabrication where no PWHT is applied. | 420 | 590 | 38 | 180 HB | 2.3 % IACS |
E308Mo-15 | Pick when the lowest hydrogen/highest deposit toughness and best out-of-position root running are needed; DC electrode positive only. | 420 | 585 | 40 | 175 HB | 2.3 % IACS |
E308Mo-16 | Most widely stocked coating type; smooth arc, easy slag removal and good bead appearance on AC or DC transformers. | 420 | 590 | 38 | 180 HB | 2.3 % IACS |
E308Mo-17 | Higher-silica rutile variant giving a flatter, wider bead and better wash-in for fillets and horizontal work. | 430 | 600 | 36 | 185 HB | 2.3 % IACS |
What is E308Mo?
E308Mo is a standard-carbon, 308-type austenitic stainless covered electrode to AWS A5.4 (UNS W30820) with a molybdenum addition that raises pitting resistance above plain E308. It is chosen for mixed 304/316 fabrications and moderate chloride service, and is supplied as -15, -16 and -17 coated electrodes for SMAW. As-welded deposits run about 420 MPa yield, 590 MPa tensile and 38 % elongation, with service to roughly 650 °C. Where the base metal is low-carbon or sections are heavy and sensitisation is a concern, E316L is the nearer choice. E308Mo has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F). E308Mo has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 64% of stainless steel grades. Elongation at break is 38% and the elastic modulus is 193 GPa (28 Msi).
What is E308Mo used for?
- mixed 304/316 fabrications
- moderate chloride service
- general stainless piping
Advantages
- Readily welded — 90/100, better than 95% of stainless steel grades
Limitations
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
E308Mo properties
Typical room-temperature values for E308Mo-AW; bars are the position among stainless steel grades.
Physical3
E308Mo has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
E308Mo has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 64% of stainless steel grades. Elongation at break is 38% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
E308Mo is rated for continuous service to 650°C (1,202 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 59% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
E308Mo conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 59% of stainless steel grades.
Sustainability4
Producing a kilogram of E308Mo takes about 55 MJ of energy and emits 5.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
E308Mo's machinability is fair (38/100, better than 63% of stainless steel grades); weldability excellent (90/100); formability good (60/100).
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. E308Mo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with E308Mo
Is E308Mo easy to machine?
Weld deposit work-hardens rapidly — use sharp carbide tools, positive rake, heavy feeds and flood coolant; grinding of caps is usually easier than machining.
Can E308Mo be welded?
SMAW with DCEP (AC also for -16/-17); keep interpass below ~150 °C, use stringer beads, no preheat, redry electrodes at 250–300 °C to avoid porosity.
Can E308Mo be formed, bent or molded?
Deposited metal is ductile but strain-hardens quickly; avoid heavy cold straightening across weld beads.
E308Mo 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 |
|---|---|---|
| Cstandard carbon grade | ≤ 0.08 | 0.05 |
| Cr | 18 – 21 | 19.5 |
| Ni | 9 – 12 | 10.5 |
| Mopitting resistance addition vs E308 | 2 – 3 | 2.5 |
| Mn | 0.5 – 2.5 | 1.4 |
| Si | ≤ 0.9 | 0.6 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cu | ≤ 0.75 | 0.15 |
| Fe | balance |
What surface finishes work on E308Mo?
Pickle and passivate (ASTM A380/A967) after welding to remove heat tint; ferrite stringers can show as faint lines after polishing.
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 E308Mo in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- W30820
- ASTM
- A5.4
How much does E308Mo cost?
E308Mo is a premium-cost stainless steel ($$$), cheaper than about 51% 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.
E308Mo — frequently asked
What is E308Mo used for?
E308Mo is typically used for mixed 304/316 fabrications, moderate chloride service and general stainless piping. In short: mo-boosted 308 electrode; bridges 304 and 316; better pitting than E308.
What is the yield strength of E308Mo?
E308Mo has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 64% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is E308Mo easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Weld deposit work-hardens rapidly — use sharp carbide tools, positive rake, heavy feeds and flood coolant; grinding of caps is usually easier than machining.
Can E308Mo be welded?
Yes — weldability is rated excellent (90/100). SMAW with DCEP (AC also for -16/-17); keep interpass below ~150 °C, use stringer beads, no preheat, redry electrodes at 250–300 °C to avoid porosity.
What surface finishes work on E308Mo?
Pickle and passivate (ASTM A380/A967) after welding to remove heat tint; ferrite stringers can show as faint lines after polishing.
Can E308Mo be formed, bent or molded?
Deposited metal is ductile but strain-hardens quickly; avoid heavy cold straightening across weld beads.
What is the maximum service temperature of E308Mo?
E308Mo is rated for continuous use to about 650°C (1,202 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between E308Mo-AW and E308Mo SOL-ANN?
AW is the default condition — default condition for all austenitic stainless SMAW deposits; use for normal fabrication where no PWHT is applied. SOL-ANN: use when the weldment is solution annealed after welding (e.g. clad or overlay parts) to dissolve carbides and restore full intergranular corrosion resistance; strength drops and ferrite is largely retained but redistributed. Yield strength is 420 MPa in AW versus 300 MPa in SOL-ANN.
How much does E308Mo cost?
E308Mo is a premium-cost stainless steel ($$$), cheaper than about 51% 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 A5.4/A5.4M — Specification for Stainless Steel Electrodes for Shielded Metal Arc Welding — American Welding Society (2012)
- ASME BPVC Section II Part C SFA-5.4 — ASME (2023)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Stainless SMAW electrode all-weld-metal datasheets (308/308Mo types) — Böhler Welding / ESAB / Lincoln Electric (2023)
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.