Tungsten insert

molybdenumtemperature-controlmold for aluminum casting

Introduction
During aluminum casting the molten metal is poured or pressed into a mold to produce components such as cylinder heads and rims. Molds and cores are repeatedly exposed to aggressive metal melts at temperatures above 600 °C. Cooling inserts made of the tungsten heavy‑metal alloy Densimet® and the molybdenum alloy TZM deliver suitable thermal and mechanical behaviour for these conditions.

Products and services
We supply cooling inserts, sprue bushes, additional mold components and semi‑finished parts. Custom inserts with integrated cooling channels can be manufactured with high precision using 3D production technologies to optimise thermal management.

Your advantages at a glance

• Shorter cycle times and increased productivity
• Improved surface quality of cast parts
• Extended mold life and reduced maintenance
• No mold cracks under thermal stress
• No internal cavities or porosity in castings
• Prevention of hotspots via targeted cooling

Material overview and specifications
Typical materials: Densimet® variants (D2M, D185) and TZM (Mo alloy). Reference specification documents: Specification D2M, Specification D185, Specification TZM.

Comparison — typical values for our materials for aluminum casting compared with hot working steel
Property | D2M | D185 | TZM | 1.2343 steel
Corrosion | + | + | ++ | --
Oxidation | from 600 °C | from 600 °C | from 400 °C | negligible
Thermal conductivity (500 °C) [W/m K] | 65 | 90 | 127 | 30
Resistance to cyclic thermal stress | ++ | ++ | ++ | --
Impact strength | - | - | 0 | ++
Tensile strength Rm (RT) [MPa] | 990 | 800 | 780 | 1200–1600
Tensile strength (500 °C) [MPa] | 670 | 600 | 500 | 100–1400
Yield strength Rp0.2 (RT) [MPa] | 700 | 600 | 730 | 1000–1400
Coefficient of thermal expansion α_th (500 °C) [10^-6 K^-1] | 5.6 | 5.2 | 5.5 | 13.0

Notes on the materials
RT = room temperature. Symbols: ++ (very good), + (good), -- (less good). TZM: molybdenum with ≈0.5 % Ti, 0.08 % Zr, 0.01–0.04 % C. D185: ≈97 % tungsten; D2M: ≈90 % tungsten (rest: Ni, Mo, Fe).

Temperature-dependent properties — selected data
D2M (typical guide values)
T[°C] | ρ [g/cm³] | c_p [kJ/kg K] | λ [W/m K] | α [10⁻⁶ 1/K] | E [GPa] | Rm [MPa] | Rp0.2 [MPa] | A5 [%]
20 | 17.3 | 0.149 | 65 | 5.3 | 360 | 990 | 670 | 18
200 | 17.2 | 0.156 | 66 | 5.5 | 350 | 890 | 600 | 17
500 | 17.1 | 0.160 | 68 | 5.6 | 333 | 700 | 460 | 16
800 | 17.0 | 0.163 | 69 | 5.7 | 320 | 490 | 330 | 14

D185 (typical guide values)
20 | 18.5 | 0.145 | 90 | 5.0 | 385 | 800 | 600 | 10
200 | 18.4 | 0.149 | 91 | 5.1 | 365 | 720 | 520 | 9
500 | 18.3 | 0.154 | 92 | 5.2 | 350 | 600 | 420 | 7
800 | 18.2 | 0.158 | 93 | 5.3 | 340 | 480 | 320 | 5

TZM (typical guide values)
20 | 10.20 | 0.256 | 148 | 5.32 | 339 | 789 | 738 | 19
200 | 10.19 | 0.266 | 137 | 5.38 | 328 | 702 | 554 | 16
500 | 10.18 | 0.281 | 127 | 5.53 | 309 | 502 | 493 | 15
800 | 10.15 | 0.296 | 121 | 5.73 | 289 | 445 | 440 | 15

1.2343 steel — representative values (for comparison)
20 | 7740 kg/m³ | c_p 0.461 kJ/kg K | λ 25 W/m K | E 217.6 GPa | α 8.7·10⁻⁶ 1/K | Rp0.2 1300 MPa | Rm 1500 MPa

Material notes and recommendations

• Molybdenum and tungsten are refractory metals with high melting points (Mo ~2610 °C; W ~3407 °C).
• Low thermal expansion (~one third of steel) and high thermal conductivity support targeted cooling and shorter cycles.
• Use D2M for high‑pressure casting (higher mechanical strength); use D185 for gravity and low‑pressure casting (higher thermal conductivity).
• TZM offers improved strength and higher recrystallisation temperature for creep resistance.
• Where erosion occurs, repair by build‑up welding with Densimet® WR filler metal is possible.

Technical characteristics / specifications

• Materials: Densimet® (D2M, D185), TZM (Mo alloy)
• Typical thermal conductivity (500 °C): D2M ≈ 65 W/m·K, D185 ≈ 90 W/m·K, TZM ≈ 127 W/m·K
• Coefficient of thermal expansion (500 °C): ~5–5.6·10⁻⁶ K⁻¹ for Densimet®/TZM; ~13·10⁻⁶ K⁻¹ for 1.2343 steel
• Modulus of elasticity: Densimet® ~360–385 GPa; TZM ~320 GPa
• Use cases: high‑pressure casting (D2M), gravity/low‑pressure casting (D185), inserts with cooling channels via 3D production
• Repair option: Densimet® WR filler metal for build‑up welding
• Coating: PVD (e.g. CrC, TiAl) or wear‑resistant coatings can be applied