Instructions for use - Shera

en
INSTRUCTIONS FOR USE
SHERAALLOY-NP
27.03.2012
GA31100A
1. General terms
SHERAALLOY-NP is a clinical proved berylium free cobalt-chrome alloy. SHERAALLOY-NP corresponds to the requirements of
DIN EN ISO 22674 and points out due to its hardness of 280 HV10.
SHERAALLOY-NP is suitable for open flame melting as well as for high frequency casting. One of its remarkable features is its
ability to be scanned by laser and its high biocompatibility.
2. Determined use
Biocompatible cobalt-chrome dental alloy with less oxide film, to be used only by dental techniciansor similarly qualified
people for dental restorations in the patient’s mouth.
3. Instructions for use
3.1 Modelling
The wall thickness of of the modelling units should not be less than 0,35 mm. Please ensure that sprues with the right
dimensions (thickness & reservoir) are attached to the full cast crown and bridge parts.
3.2. Bedding
SHERAALLOY-NP is compatible with SHERAFINA 2000, SHERAFINA-RAPID or any other phosphate-bound commercial
investments which can be pre-heated up to 900°C following the manufacturers instructions. A setting time of 30
minutes has proved to be good at the praxis.
3.3. Casting
SHERAALLOY-NP must be melted in a ceramic crucible under steamer pressure. Never use graphite crucibles. Use
always the same alloy with the same crucible and clean after use.
Flame melting and high frequency: The neutral adjusted flame with propan/oxygen or azetylen/oxygen in addition to the
non use of the fluxing agent prevents overheating of the alloy. As soon as the last cast ingots have slumped and
approximately 2 seconds after disappearance of the shade, start the casting procedure after the tear of the oxide layer.
3.4. Cool
After casting let the muffle cool slowly and at room temperature, (do not rinse with cold water). Please note that reuse
of the cast metal is not recommended as important ingredients for metal/ceramic bonding will evaporate through the
melting of the alloy. During repeated re-melting, these components decrease and a sufficient metal/ceramic bonding
can no longer be guaranteed. The units are finished using normal tungsten carbides and aluminium-oxide stones. The
minimum thickness of the finished units should be 0,2 mm. To avoid any contamination while working with different
alloys, we suggest you use the same grinding instruments.
3.5. Ceramic burn
Oxide burning can be done at 960°C for 5 minutes. Next, blast frames with 100-250 my aluminium oxide and clean as
usual with distilled water, ultrasonic or steam cleaner. Never strip non precious metal to ceramic alloys. Please process
the WAK (coefficient of expansion) wash and opaque burning according to ceramic processing instructions.
4. Soldering
SHERAALLOY-NP can be soldered with SHERALOT-N. Do not use Gold or Palladium soldering materials.
Technical data
Hardness
280 HV
Density
8.3 g/cm³
0,2% Expansion limit 550 MPa
Expansion 10,1 %
E-Modul
210,000 Mpa
Liquidus point
1,370°C
Solidus point
1,310°C
Casting temperature
1,430°C
Coefficient of Expansion (20-600°C) 14.0 x 10 -6 K -1

Chemical composition in %
Co 63.0
Cr 24.0
W 8.1
Mo 2.9
Si 1.1
further elements under 1 %
Nb
Adverse effects
Allergies against components of the alloy or electrochemical paraesthesia are rarely possible.
Warranty
SHERA Werkstoff-Technologie GmbH & Co. KG is certified according to DIN EN ISO13485 and guarantees for the products, due
to a thorough quality control system, a flawless quality of its products. Our instructions for use are based on the results of our test
laboratory. The technical data given can only be guaranteed if the processing is carried out as mentioned. The user is selfresponsible
for processing of the products. We are not liable for faulty results as SHREA has no influence on the processing.
Nevertheless possibly arising claims for damages relate to the value of the products only.
SHERA Werkstoff-Technologie GmbH & Co. KG
Espohlstrasse 53 · 49448 Lemförde · Germany
Tel.: +49 (0) 54 43 - 99 33 - 0 · Fax: +49 (0) 54 43 - 99 33 - 100
www.shera.de · info@shera.de