Walnut GRN (Green)
Finish state
Freshly sawn or wet stock — pick only for green turning, carving blanks and steam bending; strength and stiffness are far lower.
Values for the GRN condition
Other Walnut tempers and conditions
Walnut is listed in 2 conditions; see the grade overview at Walnut.
- GRN
- STM
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
GRNThis page Green | Freshly sawn or wet stock — pick only for green turning, carving blanks and steam bending; strength and stiffness are far lower. | — | 70 | — | — | 0.25 W/m·K |
Steamed and kiln-dried | Steam-conditioned before drying to darken sapwood and even out heartwood colour; choose for large panel runs needing uniform tone, at a small strength/contrast cost. | — | 95 | 1.1 | — | 0.12 W/m·K |
What is Walnut GRN?
Walnut GRN is Walnut supplied in the GRN condition — freshly sawn or wet stock — pick only for green turning, carving blanks and steam bending; strength and stiffness are far lower. Walnut GRN has a tensile strength of 70 MPa (10.2 ksi), stronger than 67% of natural material grades. Elongation at break is 1.2% and the elastic modulus is 9.8 GPa (1.42 Msi). Walnut GRN has a density of 0.9 g/cm³ (0.0325 lb/in³), heavier than 72% of natural material grades.
Advantages
- Polishes to a fine finish — 82/100, better than 84% of natural material grades
- Conducts heat well — 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 81% of natural material grades
Limitations
- Limited service temperature — 60°C (140 °F), worse than 94% of natural material grades
- Difficult to machine — 60/100, worse than 89% of natural material grades
- Needs corrosion protection — 25/100, worse than 88% of natural material grades
Walnut GRN properties
Typical room-temperature values for Walnut GRN; 11 are specific to this condition. Other listed values are Walnut reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Walnut GRN has a density of 0.9 g/cm³ (0.0325 lb/in³), heavier than 72% of natural material grades.
Mechanical9
Walnut GRN has a tensile strength of 70 MPa (10.2 ksi), stronger than 67% of natural material grades. Elongation at break is 1.2% and the elastic modulus is 9.8 GPa (1.42 Msi).
Thermal5
Walnut GRN is rated for continuous service to 60°C (140 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 81% of natural material grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical2
Walnut GRN is an electrical insulator with a dielectric strength of 3 kV/mm (76.2 V/mil) and a resistivity of 10,000 Ω·m.
Chemical & Environmental1
Corrosion resistance is poor (25/100), worse than 88% of natural material grades.
Sustainability4
Producing a kilogram of Walnut GRN takes about 10 MJ of energy and emits 0.5 kg of CO₂ — less than 56% of natural material grades. Typical recycled content is 5%.
Manufacturability2
Walnut GRN's machinability is good (60/100, worse than 89% of natural material grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Walnut GRN
Is Walnut easy to machine?
Cuts, turns and carves cleanly with sharp carbide tooling; low blunting, but figured/curly stock tears out — take light climb-free finishing passes and dust-extract (walnut dust is a sensitiser).
Can Walnut be welded?
Not applicable — joined by PVA/PUR/epoxy adhesives and mechanical joinery; oily extractives may need a fresh-sanded surface for best bonds.
Can Walnut be formed, bent or molded?
Steam bends only moderately (typical ratio ~1:15); veneer slices and flattens easily, and thin stock laminate-bends well over forms.
What surface finishes work on Walnut?
Sands to a fine surface and takes oil, shellac, lacquer or UV finishes readily; grain filler is needed for a mirror finish, and UV exposure lightens the heartwood over time.
Walnut 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 |
|---|---|---|
| celluloseoven-dry basis | 40 – 47 | 45 |
| hemicellulose | 18 – 26 | 22 |
| lignin | 20 – 25 | 23 |
| extractivestannins and juglone give the dark heartwood colour | 3 – 10 | 6 |
| ash | 0.2 – 1 | 0.5 |
Walnut GRN — frequently asked
What is Walnut GRN used for?
Walnut GRN is typically used for fine furniture, gunstocks, veneer, cabinetry and musical instruments. In short: best-machining hardwood here; stable dark heartwood; premium-cost furniture timber.
What is the tensile strength of Walnut GRN?
Walnut GRN has a typical tensile strength of 70 MPa (10.2 ksi) — stronger than 67% of natural material grades. Strength varies by condition: see the 2 listed tempers.
Is Walnut GRN easy to machine?
Reasonably — machinability is rated good (60/100, worse than 89% of natural material grades). Cuts, turns and carves cleanly with sharp carbide tooling; low blunting, but figured/curly stock tears out — take light climb-free finishing passes and dust-extract (walnut dust is a sensitiser).
Can Walnut GRN be welded?
Not applicable — joined by PVA/PUR/epoxy adhesives and mechanical joinery; oily extractives may need a fresh-sanded surface for best bonds.
What surface finishes work on Walnut GRN?
Sands to a fine surface and takes oil, shellac, lacquer or UV finishes readily; grain filler is needed for a mirror finish, and UV exposure lightens the heartwood over time.
Can Walnut GRN be formed, bent or molded?
Steam bends only moderately (typical ratio ~1:15); veneer slices and flattens easily, and thin stock laminate-bends well over forms.
What is the maximum service temperature of Walnut GRN?
Walnut GRN is rated for continuous use to about 60°C (140 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Wood Handbook — Wood as an Engineering Material, FPL-GTR-282 — USDA Forest Products Laboratory (2021)
- EN 13556 — Nomenclature of timbers used in Europe (JUGL) — CEN (2003)
- ASTM D143 — Standard Test Methods for Small Clear Specimens of Timber — ASTM (2022)
- CES EduPack natural-materials records (hardwood, longitudinal) — Granta/Ansys (2023)
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.