Tungsten Alloy EWP (WP)-BLK
Additive grade
AISI/SAE AWS A5.12 EWP · GB GB/T 4189 WP · ISO 6848 WP
BLK = as-swaged black (unground) rod
Cheapest form, oxide/lubricant film left on the surface; used for heavy AC work or where the electrode is dressed before use.
Values for the BLK condition
Other EWP (WP) tempers and conditions
EWP (WP) is listed in 3 conditions; see the grade overview at EWP (WP).
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Recrystallised | Condition of the electrode zone heated above ~1300–1500 °C in service or by anneal: coarse equiaxed grains, much lower strength and near-zero room-temperature ductility (tip splitting). | 420 | 500 | 0.5 | 35 HRC | 32 % IACS |
BLKThis page As-swaged black (unground) rod | Cheapest form, oxide/lubricant film left on the surface; used for heavy AC work or where the electrode is dressed before use. | 720 | 1,050 | 2 | 45 HRC | 30 % IACS |
GFDefault Ground (polished) finish rod, as-swaged/drawn condition | Standard stocked condition: centreless-ground bright surface for best current transfer and clean arc starts; keeps the worked (unrecrystallised) microstructure. | 750 | 1,100 | 2 | 45 HRC | 31 % IACS |
What is EWP (WP)-BLK?
EWP (WP)-BLK is EWP (WP) in the BLK grade — cheapest form, oxide/lubricant film left on the surface; used for heavy AC work or where the electrode is dressed before use. EWP (WP)-BLK has a yield strength of 720 MPa (104 ksi) and a tensile strength of 1,050 MPa (152 ksi) — weaker than 56% of tungsten alloy grades. Elongation at break is 2% and the elastic modulus is 400 GPa (58 Msi). EWP (WP)-BLK has a density of 19.25 g/cm³ (0.695 lb/in³), heavier than 76% of tungsten alloy grades. It melts at 3,422°C (6,192 °F). GF is the default condition FabDigit quotes; BLK is available on request or by drawing note.
Limitations
- Low fracture toughness — 9 MPa·√m (8.19 ksi·√in), worse than 100% of tungsten alloy grades
- Hard to polish — 60/100, worse than 83% of tungsten alloy grades
EWP (WP)-BLK properties
Typical room-temperature values for EWP (WP)-BLK; 22 are specific to this condition. Other listed values are EWP (WP) reference data and may not represent this condition. Bars are the position among tungsten alloy grades.
Physical3
EWP (WP)-BLK has a density of 19.25 g/cm³ (0.695 lb/in³), heavier than 76% of tungsten alloy grades. It melts at 3,422°C (6,192 °F).
Mechanical16
EWP (WP)-BLK has a yield strength of 720 MPa (104 ksi) and a tensile strength of 1,050 MPa (152 ksi) — weaker than 56% of tungsten alloy grades. Elongation at break is 2% and the elastic modulus is 400 GPa (58 Msi).
Thermal5
EWP (WP)-BLK is rated for continuous service to 450°C (842 °F). It conducts heat at 168 W/m·K (97.1 BTU/hr·ft·°F), better than 76% of tungsten alloy grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical3
EWP (WP)-BLK conducts electricity at 30 % IACS, better than 64% of tungsten alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), better than 64% of tungsten alloy grades.
Sustainability4
Producing a kilogram of EWP (WP)-BLK takes about 380 MJ of energy and emits 25 kg of CO₂ — less than 62% of tungsten alloy grades. Typical recycled content is 20%.
Manufacturability7
EWP (WP)-BLK's machinability is not recommended (10/100, better than 52% of tungsten alloy grades); weldability poor (15/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with EWP (WP)-BLK
Is EWP (WP) easy to machine?
Effectively non-machinable by turning; shape by diamond/SiC wheel grinding, EDM or laser, always grinding longitudinally on a dedicated wheel with dust extraction.
Can EWP (WP) be welded?
Not a structural weld material — it is the non-consumable electrode; joining W itself requires EB or diffusion bonding because fusion causes recrystallisation embrittlement.
Can EWP (WP) be formed, bent or molded?
Made by powder pressing, sintering and hot swaging/drawing above ~1200 °C; no cold forming — rods snap rather than bend at room temperature.
What surface finishes work on EWP (WP)?
Supplied centreless-ground or chemically cleaned; ball the tip on AC for aluminium/magnesium and re-dress the tip rather than plating or coating.
EWP (WP) 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 |
|---|---|---|
| Other elements, totalimpurities per AWS A5.12 / ISO 6848 for WP | ≤ 0.5 | 0.3 |
| Wno intentional oxide additions (green colour code) | ≥ 99.5 (balance) | — |
EWP (WP)-BLK — frequently asked
What is EWP (WP)-BLK used for?
EWP (WP)-BLK is typically used for AC TIG welding of aluminum, magnesium welding and general-purpose GTAW. In short: lowest-cost TIG electrode; green-band AC aluminium electrode; no radioactive thorium.
What is the yield strength of EWP (WP)-BLK?
EWP (WP)-BLK has a typical yield strength of 720 MPa (104 ksi) and a tensile strength of 1,050 MPa (152 ksi) — weaker than 56% of tungsten alloy grades. Strength varies by condition: see the 3 listed tempers.
Is EWP (WP)-BLK easy to machine?
Not especially — machinability is rated not recommended (10/100, better than 52% of tungsten alloy grades). Effectively non-machinable by turning; shape by diamond/SiC wheel grinding, EDM or laser, always grinding longitudinally on a dedicated wheel with dust extraction.
Can EWP (WP)-BLK be welded?
Not readily — weldability is rated poor (15/100). Not a structural weld material — it is the non-consumable electrode; joining W itself requires EB or diffusion bonding because fusion causes recrystallisation embrittlement.
What surface finishes work on EWP (WP)-BLK?
Supplied centreless-ground or chemically cleaned; ball the tip on AC for aluminium/magnesium and re-dress the tip rather than plating or coating.
Can EWP (WP)-BLK be formed, bent or molded?
Made by powder pressing, sintering and hot swaging/drawing above ~1200 °C; no cold forming — rods snap rather than bend at room temperature.
What is the maximum service temperature of EWP (WP)-BLK?
EWP (WP)-BLK is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between EWP (WP)-GF and EWP (WP)-RX?
GF is the default condition — standard stocked condition: centreless-ground bright surface for best current transfer and clean arc starts; keeps the worked (unrecrystallised) microstructure. RX: condition of the electrode zone heated above ~1300–1500 °C in service or by anneal: coarse equiaxed grains, much lower strength and near-zero room-temperature ductility (tip splitting). Yield strength is 750 MPa in GF versus 420 MPa in RX.
Sources
- AWS A5.12M/A5.12 Specification for Tungsten and Oxide Dispersed Tungsten Electrodes for Arc Welding and Cutting — AWS (2009)
- ISO 6848 Arc welding and cutting — Nonconsumable tungsten electrodes — Classification — ISO (2015)
- GB/T 4187 — SAC/ (2017)
- ASM Handbook Vol.2: Properties and Selection — Nonferrous Alloys and Special-Purpose Materials (refractory metals) — ASM International (1990)
- Tungsten — material properties and product data — Plansee SE (2023)
- CRC Handbook of Chemistry and Physics (thermophysical data for W) — CRC Press (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.