Walnut STM (Steamed and kiln-dried)
Grade
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.
Values for the STM 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 |
|---|---|---|---|---|---|---|
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 |
STMThis page 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 STM?
Walnut STM is Walnut in the STM grade — 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. Walnut STM has a tensile strength of 95 MPa (13.8 ksi), stronger than 78% of natural material grades. Elongation at break is 1.1% and the elastic modulus is 11 GPa (1.6 Msi). Walnut STM has a density of 0.6 g/cm³ (0.0217 lb/in³), lighter than 66% of natural material grades.
Advantages
- Polishes to a fine finish — 85/100, better than 87% of natural material grades
Walnut STM properties
Typical room-temperature values for Walnut STM; 14 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 STM has a density of 0.6 g/cm³ (0.0217 lb/in³), lighter than 66% of natural material grades.
Mechanical9
Walnut STM has a tensile strength of 95 MPa (13.8 ksi), stronger than 78% of natural material grades. Elongation at break is 1.1% and the elastic modulus is 11 GPa (1.6 Msi).
Thermal5
Walnut STM is rated for continuous service to 90°C (194 °F). It conducts heat at 0.12 W/m·K (0.0693 BTU/hr·ft·°F), worse than 70% of natural material grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical2
Walnut STM is an electrical insulator with a dielectric strength of 3 kV/mm (76.2 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental1
Corrosion resistance is fair (50/100), better than 63% of natural material grades.
Sustainability4
Producing a kilogram of Walnut STM 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 STM's machinability is excellent (88/100, better than 76% of natural material grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Walnut STM
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 STM — frequently asked
What is Walnut STM used for?
Walnut STM 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 STM?
Walnut STM has a typical tensile strength of 95 MPa (13.8 ksi) — stronger than 78% of natural material grades. Strength varies by condition: see the 2 listed tempers.
Is Walnut STM easy to machine?
Yes — machinability is rated excellent (88/100, better than 76% 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 STM 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 STM?
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 STM 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 STM?
Walnut STM is rated for continuous use to about 90°C (194 °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.