For perfect aluminum casting.
We supply tailor-made mold inserts, sprue bushes, cooling inserts and other individual parts as well as semi-finished products for your mold.
Cracks and corrosion.
Why traditional molds have difficulties.
Frequent temperature cycles also subject tools and components to stress during metal casting: Variations in temperature distribution and different coefficients of thermal expansion lead to thermal stress. Cracks and distortion resulting from thermal fatigue can cause complete failure of the component.
The ideal material for molds used for aluminum casting thus has to meet the very highest mechanical, thermophysical, chemical and tribological requirements. Traditional hot working steels using alloy additives such as chromium and molybdenum do not live up to expectations. So what can be done? Anyone wishing to save money and increase productivity in the aluminum casting process should use top-quality materials for the molds, which take the brunt of the wear and tear.
The properties that are needed are chemical resistance against metal melts, high thermal conductivity and good high-temperature stability.
Our materials for aluminum casting.
The high modulus of elasticity of 360 GPa to approx. 385 GPa guarantees ample rigidity even at high temperatures. The mechanical properties of molybdenum and tungsten depend on their level of cold working, their purity and their level of recrystallization. Stability at room temperature is below that of tempered hot working steels. At 650 °C, stability is comparable to that of hot working steel.
|Typical values for our materials for aluminum casting compared with hot working steel|
|Oxidation||from 400 ºC||from 600 ºC||from 600 ºC||negligible|
Thermal conductivity (500ºC) [W/m K]
|Resistance to cyclic thermal stress||++||++||++||--|
|Tensile strength Rm (RT*) [MPa]||780||990||800||1200 - 1600|
|Tensile strength Rm (500ºC) [MPa]||500||670||600||850 - 1100|
|Yield strength Rp0.2 (RT*) [MPa]||730||700||600||1000 - 1400|
|Yield strength Rp0.2 (500ºC) [MPa]||490||460||420||650 - 900|
Elongation at failure A5 (RT*) [%]
|19||18||10||10 - 15|
|Elongation at failure A5 (500ºC) [%]||15||16||7|
|Modulus of elasticity [GPa]||320||360||385||214|
|Coefficient of thermal expansion αth (500ºC) [10-6 K-1]||5.5||5.6||5.2||13.0|
|Hardness [HRC]||25||max. 31||max. 31||> 45|
*RT = room temperature
TZM: Molybdenum with 0.5% titanium and, 0.08% zirconium, 0.01-0.04% carbon
D185: 97% tungsten, remainder: nickel and iron
D2M: 90% tungsten, remainder: nickel, molybdenum and iron
Molybdenum alloy TZM.
The physical properties of TZM differ very little from those of pure molybdenum. But small quantities of extremely fine carbides make TZM more resilient than pure molybdenum and give it a higher recrystallization temperature and greater creep resistance.
Tungsten alloys D2M and D185.
We primarily manufacture our inserts for aluminum casting from DENSIMET® 185 (D185) and DENSIMET® D2M. Due to its greater mechanical strength, our customers mostly use D2M for high-pressure casting applications. Its particularly good thermal conductivity means that D185 is predominantly used in gravity and low-pressure casting applications to ensure optimum temperature distribution in the mold. We would be delighted to advise you and find the right material for your application.
DENSIMET® WR: Getting the most out of your mold.
Rapid heat dissipation. Short cycle times.
The high thermal conductivity of molybdenum and tungsten allows heat to be dissipated rapidly, thus ensuring a low temperature difference between the surface of the mold insert and the core of the casting.
The surface hardness of hot working steel molds begins to lessen after a certain number of casting operations. In the case of refractory metals, on the other hand, no reduction in hardness is observed, although they start from a lower strength level.
Because it is not possible to harden molybdenum and tungsten with traditional heat treatment methods, a protective coating can be applied to the finished component. Traditional PVD coatings such as CrC or TiAl are suitable for this purpose. We also offer our own wear-resistant coating that increases surface hardness to more than 1000 HV without having any impact on the corrosion resistance of the material. Interested? Just contact us!
High corrosion resistance.
Traditional mold inserts and cores are particularly susceptible to erosion when aluminum is injected at high speeds. Molybdenum and tungsten do not dissolve in an aluminum melt. Mold inserts made from DENSIMET® and TZM are particularly resistant to erosion and corrosion. Because our material does not react with the aluminum melt, no metal residues continue to adhere to the mold insert, for example when the castings are removed. The benefit to you: The inserts can be used for longer, do not have to undergo time-consuming cleaning operations and are soon ready for the next pouring.
Goodbye casting defects.
Hello molybdenum and tungsten.
The good thermal conductivity properties of molybdenum and tungsten alloys also speed up your processes. Significantly higher cooling potential = faster cycle times.
Thermal image of a mold after opening. Steel cores at positions D and E.
Thermal image of a mold after opening. TZM cores at positions D and E.
Source: TCG UNITECH AG
The very best of recommendations.
DENSIMET® is machined in much the same way as hot working steel. But please take note of our machining recommendations in the tables below. Molybdenum materials can also be machined well. They nevertheless have certain properties that need to be taken account of during machining. Please follow our guidelines. For machining molybdenum, we recommend hard metal tools with positive cutting geometry from CERATIZIT.
You can achieve complex shapes and perforations by spark erosion. In this process, the molybdenum or tungsten alloy acts as the anode and the working electrode acts as the cathode. We recommend our SPARKAL® electrodes as the electrode material for spark erosion. SPARKAL® elektrodes.
TZM molybdenum alloy.
|Tools||CERATIZIT Maxilock-S with Code-27 und -25, hard metal grades H 216 T / H 210 T|
|Cutting speed [m/min]||vc = 100 - 140|
|Feed [mm/U]||f = 0.05 - 0.35 (depending on corner radius)|
|Cutting depth [mm]||ap = 0.3 - 0.6 (depending on type of insert)|
|Drilling, drill diameter up to 18 mm|
|Drill bit||HSS (preferably with internal coolant duct)|
|Cutting speed [m/min]||vc = 10 - 15|
|Feed [mm/U]||f = 0.05 - 0.10|
|Inserts||Hard metal grades H 10 T / H 20 T|
|Cutting speed [m/min]||vc = 300 full cooling with emulsion|
|Infeed||ap = 0.002mm / pass|
Oxidation: In air or any oxygenous atmosphere at temperatures up to 400 °C, oxidation of molybdenum is negligible. At temperatures above 600 °C severe oxidation or sublimation takes place.
DENSIMET® tungsten alloys.
|Hard metal grades||H 216 T / H 210 T (CERATIZIT)|
|Drill diameter||< 18mm|
|Drill bit||HSS or hard metal twist drill|
|Cutting speed [m/min]||
Hard metal: 30
HSS: ≥ 8 - 15
|Drill diameter||≥ 18mm|
|Drill bit||Short hole drill|
|Cutting speed [m/min]||Hard metal: 70 - 160|
|Indexable inserts||WCGT grade U 17 T|
|Cutting speed [m/min]||vc = 70 - 100|
|Feed [mm]||f = 0.03 - 0.10|
Nitrided stainless steel thread cutter, straight fluted with tensile strength of 1400 N/mm2
Oxidation: DENSIMET® tungsten alloys start oxidizing slightly as of 600 °C. However, experience in the casting industry shows that no problems arise. The temperature of the mold when it is opened is somewhere between 400 °C and 500 °C and commonly applied coatings offer additional protection. When the mold is filled, the melt displaces the atmosphere, thus preventing oxidation. Components such as thermowells which are simultaneously exposed to the melt and to oxygenous atmospheres will generally need to be protected against oxidation.
Material data for finite element simulation.
|TZM rod, 25 mm diameter, stress-relief annealed, data from tensile test|
||λ [W/m K]||
|E [GPa]||Rm [MPa]||Rp0.2[MPa]||A5 [%]|
||E [GPa]||Rm [MPa]||Rp0.2 [MPa]||A5 [%]|
||E [GPa]||Rm [MPa]||Rp0.2 [MPa]||A5 [%]|
Sure and certain.
|Ever since 1921, our customers have been able to rely on PLANSEE as an independent private company. Like us, they place great importance on reliability and continuity – especially when it comes to raw materials procurement. With Global Tungsten & Powders (GTP) and a holding in Molibdenos y Metales (Molymet), the Plansee-Group covers all the stages involved in the processing of tungsten and molybdenum – from powder manufacture through the subsequent powder metallurgy processes and on to the production of semifinished products and customer-specific components.|
Three paths. One goal: The perfect alloy.
High-temperature infiltration, liquid phase sintering and back-casting are all used to produce high-performance composite materials with outstanding properties. Our competence center – PLANSEE Composite Materials – combines such diverse material properties as density, corrosion resistance, thermal conductivity and thermal expansion, temperature resistance and mechanical stability during the development of its composites.
We work in close collaboration with our customers in the foundry, medical technology, automotive and other industries to turn their ideas into reality. Join them and contact us!