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- Steel
Stainless steel
To manufacture steel products we use stainless steel AISI 304 (18/10 type), an alloy composed by 18% of chrome, 10% of nichel and a percentage of carbon not higher that 0.03%. This type of steel is usually called "stainless" thanks to its high resistance to corrosion, which is the result of a very thin chromic oxide film generated on its surface by the reaction between the chrome component of steel and the oxygen of the air.
The nichel component of steel not only improves considerably the resistance to corrosion but also increases the material malleability, that is the material capacity to be moulded with no cracking.
Nevertheless the stainless steel resistance to corrosion can be undermined by any external factors which might prevent the chromic oxide film to generate, such as a prolonged contact with food residuals, salt, acids etc.
Therefore it is not correct to believe that stainless steel is absolutely indestructible and corrosion safe.
The resistance and duration of a stainless steel object certainly depends on a correct selection of the material and well made manufacture by the producer but is also affected by the correct use and maintenance done by the consumer.
As a matter of fact do exist materials and products which, if put in contact with stainless steel, might damage it surface. However it is possible to avoid any kind of inconvenience simply by following cleaning and maintenance instructions.
Steel
Steel production starts from melting of iron mineral, generally magnetite, coming from mills in High Silesia (Poland), Ruhr fields (Germany), Pennsylvania (U.S.A.), Elba Island and Cogne in Italy, in a blast furnace -a frustum tower- shaped system reaching 30 meters in height.
At a temperature of 1200°C the blast furnace produces liquid cast iron that is transferred then to other systems, so-called Bessemer convertors, that by combustion and blowing in air through a number of nozzles, reduce the percentage of carbon, and transform the liquid cast iron bath into steel. Proper additions of metals convert this bath into special steels, among those stainless steel, whose main characteristic is it cannot be attacked by oxids (rust) in the presence of chemical agents.
The most common metals in stainless steel alloys are nickel and chrome, in varying percentages depending on the use they are meant for, with the addition of small parts of copper and mobdilenum.
Now, the liquid bath, already modified by the addition of metals to form an inoxidizable alloy, is poured into special moulds, so-called ingot moulds, so, after cooling down and solidifying, an ingot is got that, by suitable rolling-milling, is transformed into sheets or section bars of different shapes.
The most widely used types of stainless steel in the household article field are:
- AISI 420, martensitic-structure stainless steel, used to manufacture knives;
- AISI 430, also known as 18/C, used to manufacture low-quality cutlery and kitchen-ware; in fact, it has only an 18% chrome content and does not ensure an excellent resistance to corrosive agents;
- AISI 304, also known as 18/10, mainly used for top-quality cutlery and kitchen-ware. Its contents of 18% chrome and 10% nickel highly increase production costs, however ensuring unalterability of every item.
(the acronym AISI refers to an American Standard - American Institute of Steel and Iron - well known all over the world).
(La sigla AISI è la sigla normativa americana - American
Institute Steel and Iron - ormai riconosciuta internazionalmente).
Cleaning instructions
Carefully clean the product prior to its first use with suitable detergents.
In the case of dishwasher use, in order to prevent that small rust spots appear on the knives always place them in a separate basket of the washing machine to a avoid contact with other cutlery pieces and preferably with their blade downwords.
Once the washing cycle is over do not leave the knives into closed dishwasher for a long time but dry them as soon as possible with a soft cloth.
If small black burning spots appear onto the knives after dishwashing we suggest you to get the correct grounding of your washing device checked by an electrician.
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Le Pentole stainless steel cookware main features
- Cold rolling of cylindrical parts.
- Three-ply bottom (stainless steel+copper+steel) of different thickness for better heat distribution and superior energy save.
- Deformation proof rims up to 100 Kgs. pressure.
- Half-dome steam stop lids to prevent steam from falling outside or into the pot.
- MIXER aluminium non stick cookware main features
- Body made of 99.5% pure aluminium certified for contact with food, 4 mm thick
- Triple non stick internal coating of superior resistance reinforced with ceramic parts and tested with the method of reciprocal abrasion
- Double external non stick coating
- Anti-slip straightened base
- Ergonomic handles made of 18/10 stainless steel
- Lids made of 18/10stainless steel, hygienic, safe and easy to clean
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Cutlery and holloware cold manufacturing process
Cutlery
The company purchases steel from steel mills, that supply coils or 1x3-meter sheets with a thickness ranging between 0.8 and 4 mm, for cold machining (kitchen-ware and cutlery), or steel round rods with different diameters, for hot machining.
AISI 304 stainless steel, having a 10% nickle and 18% chrome content, is used here.
Machining is called "cold-machining" because every plastic deformation, i.e. forging strain, is carried out without heating "pieces".
Morinox make use of sheets with a 2 to 4 mm thickness for their cutlery.
It is clear that the thicker (for example our 4-mm thick cutlery lines ELLA and GEO) the worthest an item is, both because the machining involved is more complex, and also because an item weight and, consequently, the cost of raw material are remarkably increased to the advantage of appearance and solidity.
PRODUCTION CYCLE (not for knives):
- Trimming of blanks, i.e. of a piece outline
- Rolling, to make spoon scoops or fork teeth thinner
- Blanking of spoon scoops or fork teeth
- Degreasing, to remove blanking oils
- Coining, to give final shape and drawing to pieces
- Polishing by means of abrasive pastes
- Washing to remove residual abrasive pastes used to polish
- Gold-plating, if any
Holloware
18/10 (AISI 304) stainless steel is used, in sheets of varying thickness, 0.8 to 1.2 mm, ordered to the steel mill specifying "to be used for kitchen-ware", since sheets need to have a surface free of pricks or other aesthetical defects.
Every plastic deformation to get the shapes wished are cold-made, making sure that there is a small layer of lubricant between moulds and sheets to be pressed, so to avoid any scratches on the surfaces.
PRODUCTION CYCLE (for example BOMBEé tray):
- Shearing of sheets in square blanks
- Drawing to give depth to items (consequently, the more drawings, the most deep the piece. BOMBE trays need 2 drawing steps)
- Blanking of blanks, i.e. piece outline
- Degreasing to remove blanking oils
- Polishing
- Washing
- Gold-plating, if any.
A curiosity: AISI 304 - 18/10 steel is not attracted by a magnet, while AISI 420 - 18/C one is magnetized: try to believe it!
- Manufacturing process for Le Pentole cookware
18/10 (AISI 304) stainless steel is used for the body of the pot, in discs of 1.5mm thick, specific type for deep pressing.
Copper disc insert of 1mm thick and 18/C (AISI 430) external capsule is used for the bottom. Every plastic deformation to get the cylindrical body of the pot is cold-made, as for the holloware, by static pressure procedure making sure that there is a small layer of lubricant between the moulds and the discs to be pressed, so to avoid any scratches on the surfaces
Production cycle:
- Drawing to give the first depth to the body of the pot
- Cold rolling by spinning lathe to lengthen the pot as much as needed
- Calibration of the body so as to create an uniform step beneath the rim for shiny/mat polish
- Rim drawing
- Rim edging
- Degreasing to remove blanking oils
- Braze welding of the steel capsule + copper disk to the bottom of the pot with the application of silver alloy,
- Polishing
- Handles welding
- Washing
A curiosity: The application of 18/C (AISI 430) capsule to the bottom makes Le Pentole pots and pans suitable for induction.
- Manufacturing process for MIXER aluminium non-stick cookware
Aluminium discs/sheets of 4 mm thick, suitable for contact with food and specific for non-stick coating process are used. Every plastic deformation is cold-made, as for the holloware, by static pressure procedure making sure that there is a small layer of lubricant between the moulds and the discs to be pressed, so to avoid any scratches on the surfaces.
Production cycle:
- Drawing to give depth to the body of the pot
- Rim edging
- Pickling to remove any residuals of drawing oil
- Lapping so as to make the surface of the pot rough in order to assure a better non-stick coating application
- Non stick coating application
- Grinding of the bottom so as to make it non-slip
- 18/10 stainless steel handles application with riveting machine.
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