3. DESIGN FEATURES 2011
4.CHARACTERISTIC OF EXISTING HEAT-RESISTANT STEEL.
EXPRESSIONS AND COMMENTARIES
5. MODEL SERIES
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Updated design. Decorative external parts were produced with the use of modern technologies.
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The concept of thermal strength uniformity that prolongs the service life of the bath stove was embodied.
The thickness of fire chamber details, exposed to the highest thermal load was increased up to 50%.
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External casing was made solid, ventilation holes are only at the front wall for the maximum screening off
from the high-level infra-red radiation emitted from the fire chamber.
Steel used in manufacture of stoves "Tunguska" - is heat-resistant, highly alloyed, corrosion resistant
(stainless) in accordance with above stated characteristics.
Heat-resistant or scaling resistance means capacity of metal to stand against corrosive attack of gases at high
temperatures (not to be confused with high-temperature strength).
Heat-resistant of steel is enhanced by chrome doping. Chrome creates an inactive film on a surface of steel,
which does not be subjected by corrosion till limiting temperature called as temperature of oxide scale formation
beginning.
Heat-resistant of steel and temperature of oxide scale formation beginning rises with increase of chrome
content.
Steel is deemed heat-resistant when it contents mass fraction of chrome 13 % and more.
Steel divides into low-alloyed, medium-alloy and highly alloyed depending on alloying elements content.
Steel is deemed highly alloyed when it contents alloying elements 10% and more.
Colloquially, popular phrase "stainless steel" is not standardized expression. Expression "corrosion resistant
steel" corresponds with this expression in modern materials science.
A key differentiator of corrosion resistant steel is chrome content 12,5% and more.
Temperature of oxide scale formation beginning of applied steel is not less 750C
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, and it is confirmed by
certificates of manufacturers.
For comparison: temperature of oxide scale formation beginning of constructional or "carbon" steel is no more
than 400C
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, it is greatly low than temperature of walls of functioning wood-burning stove.
Heat-resistant steel is more expensive than traditionally applied "carbon" steel. Its share in manufacturing
costs of stove corresponds near 50%. Therefore, in the process of selection chemical compositions of steel, a
manufacturer excludes those alloying elements and technical operations its processing which don't increase heat-
resistance and lead to unjustified increase in the cost.
Stereotypical perception of stainless steel as mirror surface is erroneous. Mirror surface of household stainless
steel products is achieved by special expensive removal of dark oxide film from surface of sheet. This action is not
needed under manufacture of wood-burning stoves.
The manufacturer considers that buyers of stoves "Tunguska" shall only pay for those special characteristics of
steel which are needed for its using into wood-burning stoves.
Upon storage and operation of stoves in condition of higher humidity, traces of surface corrosion on non-
painted area are allowed. These traces don't influence upon operational characteristics of product.
Basic models «Tunguska 2011», «Tunguska 2011 Vitra», «Tunguska XXL 2013» and «Tunguska XXL 2013
Vitra» are produced in lots. These models have general surface appearance, design features and operating principle.
Differences between models consist in capacity size of a steam room, dimensions, a type of fuel canal and door of the
stove.
The models «Tunguska 2011» and «Tunguska XXL 2013» have modification with a short fuel canal.
All models can be completed by fixed heat exchange unit. The stove has various color version of a convector.
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