Glossary

AISI (American Iron and Steel Institute)

North American Association with 50 member companies and more than 100 associated members. These companies represent the United States, Canada and Mexico in all aspects of the steel industry

ALLOY

A homogeneous mixture (mostly solid solution containing, where appropriate, particles of intermetallic or carbide compounds) in which two or more elements are present. For example, Alloy Iron with percentages more or less relevant to Carbon and other elements (Cr, Mn, Ni, Mo, W etc.) forms steels.

ALLOY ELEMENT

Adding any metallic element to steel production to increase hardness, strength or corrosion resistance. Molybdenum, nickel and chrome are the most common alloy elements in stainless steel.

ALUMINUM

Aluminum is the chemical element of atomic number 13. Its symbol is Al Aluminum alloys, also known as light alloys, are alloys obtained mainly by the combination of aluminum and copper, zinc, manganese, silicon, or magnesium. The main characteristics of these alloys are low density, high ductility, high thermal conductivity and electrical conductivity, low melting point and corrosion resistance in an atmosphere of some types of corrosion and are therefore treated with procedures Such as anodizing or applying paint Aluminum alloys can develop rapid galvanic corrosion phenomena if they come into contact with stainless steel or titanium and its alloys.

AUSTENITIC STEEL

Non-magnetic steels, generally well-weldable, containing nickel and 18% chromium to increase corrosion resistance. Austenitic steel is the most common steel category

BRASS

The copper alloy (Cu) and zinc (Zn) alloy, whose content determines properties such as mechanical strength, color, toolability, ductility, conduction of electricity and heat, resistance Abrasion and corrosion.

BRASS ROD

Semi-finished round, hexagonal and square section in rods, rolls and reels, with excellent workability at the tool, allowing high speed machining.

BREAST CHARGE

Defines the load that steel can withstand before breaking. Usually verified with standard test tubes.

BRINELL HARD TEST

Test to determine the hardness of a material by the use of a spherical steel sphere of specific c diameter to which a certain load is applied. The result is expressed as a Brinell hardness number obtained by dividing the applied load in kg for the fingerprint surface obtained in mm 2.

CARBON

Carbon is the chemical element of the periodic table of the elements which has the C symbol and atomic number 6. It is a non-metallic, tetravalent element.

CAST

Sets of steel or cast iron made in a series of operations in the furnace. The term is therefore used to designate the set of semi-products deriving from the same kiln charge and thus having the same composition.

CHARGE OF SNAPSHOT

Stress to which the metal shows an obvious deviation from the proportionality between stress and deformation. A deviation of 0.2% is usually used for different metals.

CHROME (CR)

Alloy element that is used in stainless steel to prevent corrosion.

COLD ROLLED COILS (Sheet)

The steel sheet is passed through a cold reduction mill. Cold rolled steel is thinner and stronger than the hot rolled sheet and is more expensive.

COIL

Rolled steel sheet to facilitate transportation and storage.

COLD ROLLING

The peculiar characteristic of cold rolling compared to hot rolling lies in the characteristics of rolling mills. Cold holders have a great structural rigidity to ensure high precision in shape and flatness of the tape. They are sized to apply the high specific pressures between the work cylinders and the belt, which are necessary for the cold deformation of hot-rolled and properly softened materials.

CONTINUOUS FURNACE

Furnace used for treatments that progress continuously, with the metal coming in from one side and coming out of the other.

COPPER

Is the chemical element of atomic number 29. Its symbol is Cu. As a metal, it has many qualities that make it very useful for today's world. The mechanical properties of copper are determined by its hardness, shape and ductility, are designated by the letter H for hardness and the letter R for breaking load. Copper can thus be supplied in the desired physical state, obtainable through thermal cycles or cold machining. Copper has high malleability and ductility, ie the ability to deform in laminates and wires. It can therefore be easily machined for plastic deformation with excellent results.

CORROSION

The natural degradation of steel due to weather conditions or other factors.

DRAWN

Product having different straight section forms, obtained by cold deformation without material removal. This process gives the product special characteristics of shape, dimensional precision and surface layer. Product obtained by drawing, generally these are tubes or round bars.

EXTRA ALLOY

Producer's sales price with a supplement / charge added to compensate / balance the rise in the cost of the base materials due to the rise in the price of the alloy.

FERRITIC

Magnetic, non-temprable steel having a low carbon content and containing chromium as the major alloy element usually ranges between 13% -17%. The second most commonly used steel. Ferritic steels are generally used in motor and exhaust systems, water tanks and in the interior architectural structure.

FINISHING

Condition of presentation of the stainless product, generally definable in terms of brilliance and / or roughness.

FLAT LAMINATE

Thin thickness and wide width material, obtained by hot and / or cold rolling.

FLATNESS

Deviation of the horizontal plane of a laminate under its own weight.

FOLDING

Bending of sheets and strips is carried out on bending presses. Although all the steels may be subjected to this type of forming, the austenitics are the most performing.

GRINDING

It is obtained in the most used form starting from finishing 2B by means of abrasive brushes; Gives the sheets a brilliant "brilliant" look

HARDENING

The thermal treatment operation consists in bringing the steel to the austenitization temperature and then cooling it with the most suitable extinguishing means (water, oil, salts, etc.) to cause the formation of martensite.

HARDENING

Increasing the hardness of a metal usually linked to a heating followed by a cooling. The cold deformation acts through the build up of reticulate defects in the crystalline grain which hinder further deformation. The material can be returned under the original conditions with a suitable heat treatment.

 HARDWARE

Hardness can be defined as metal resistance to penetration. Various measurement methods, such as Brinell, Vickers, Rockwell and Knoop, can be used, which, as is known, are distinguished by the type of penetrator used and the applied load. Flat-rolled stainless steel is generally used in the Rockwell method.

HARDWARE KNOOP

Microhardness determined by metal resistance to penetration by a diamond-based pyramid based of rhomboid shape.

HOT ROLLING

In hot-rolled coil operations, the ingot, rectangular section, is heated in wells up to the upper limit of the rolling temperature reaching 1230 ° C for austenitic steels and 1130 ° C For ferritic steels. Subsequently, the thickness is obtained by repeating passes on various types of laminate at a constant temperature around 900 ° C. Appropriate thermal treatments are followed and finally decapping operations.

LASER CUTTING

"Laser" is the abbreviation "Light amplification by stimulated emission of radiation". It is a source of electromagnetic radiation. The cutting is carried out using a laser beam on the workpiece to be cut, producing a vaporisation fusion limited to the cutting area. In practical execution, a nozzle directs a high-speed jet to remove the material from the bottom of the workpiece, thus obtaining a very thin slot.

LENGTH

Measurement of the deformation suffered until breaking (standard test tubes are used).

LOW CARBON STEEL

Steel containing less than 3% carbon. This steel is very ductile and can be elongated or rolled up for mechanical parts.

MARBLED

Surface finish typical of the wine and wine sector vessels but also used in the automotive industry for heavy-duty mudguards. It is obtained as a result of mechanical circular mechanical abrasion on both tape and sheet metal. The marble (and therefore the swab that abrades the sheet) may have variable diameter and pitch.

MARTENSITICAL

A small stainless steel category that contains 12% chrome, a low carbon content and a low nickel content.

MECHANICAL PROPERTIES

Properties of a material related to its elastic and plastic behavior in the event of stress being applied. Applications to which this material may be devoted depend, for example, on the elastic modulus, traction resistance, elongation, hardness and fatigue limit

METAL

Each chemical element with a crystalline, ductile and malleable structure, characterized by good thermal and electrical conductivity, high specific weight and reflective power, chemically electrophoretic, naturally occurring in nature, most often in compounds (oxides, sulphides, sulphates, carbonates ).

MOLYBDENUM

Atomic number 42, symbol Mo. It is a transition metal and in the natural state it is of silvery white color. It is a very hard metal and among the elements is one characterized by one of the highest melting points. In small quantities it has a hardening effect on the steel.

NICHEL (Ni)

Alloy element used in stainless steels to improve its ductility and corrosion resistance. Nickel is one of the five ferromagnetic elements and is highly appreciated for the properties it gives to the metal alloys it is part of. Due to its excellent resistance to oxidation, nickel is widely used (around 65% of world consumption) for the production of austenitic stainless steel and another 12% is used for the production of superalloys.

NON-FERROUS METAL

Metal or alloy containing no iron.

OXIDATION

Rust or corrosion caused by exposure to oxygen.

PASSIVATION

Anglosaxon meaning (stainless steel) designates the ability of these materials to oxidize but does not rust (or passivate) in the atmospheric and natural environments. The passivation phenomenon occurs by reaction of the metal with the oxidizing environment (air, water, various solutions, etc.) In particular, the passive film may be more or less resistant depending on the concentration of chromium in the alloy and in relation to the presence of other binding elements such as nickel, molybdenum, and titanium.

PLASMA CUTTING

Plasma is a gas (a mixture of argon and hydrogen or nitrogen) made electrically conductive for ionization. By recombination on the workpiece, the energy already involved in dissociation and ionization frees up and you can also overcome temperatures of 25,000 ° K. This technique is largely used mainly with heavily bonded steels such as stainless steels. In plasma cutting, the energy is electrically powered from the outside and the cutting can be carried out both manually and automatically on thicknesses from a few millimeters to several tens of millimeters.

 PHYSICAL PROPERTIES

Metal or alloy properties that are relatively independent of the microstructure and which can be measured without applying a force (for example, density, electrical conductivity, coefficients

PROTECTIONS

For the protection of flat iron products, the paper, used to interleave the sheets, is generally adopted. For high-quality finishes, plastic, opaque or transparent, adhesive films are used. Plastic has the advantage over the paper to be more deformable and to allow the material even more sliding. Generally, the plastic is removed from the surface only after finishing (sometimes even after assembly), preserving the surface during all processes.

RECTANGULAR (ROD)

Finished product hot-rolled, forged or drawn, in rectangular section bars.

RESILIANCE

Steel resistance to impact; Is determined by subjecting a steel sample of unified shape to the impact of a particular mesh. Specifically, resilience is defined as the energy per unit of volume absorbed by a material that is fraught with breakage. Resilience is measured by subjecting a sample of the same shock-proof material through a pendulum-shaped pendulum (Charpy pendulum) and is obtained directly by calculating the difference between the initial height from which it is dropped and the height Which reaches after breaking the sample of the material under test.

RESISTANCE

The resistance of materials can be calculated using different methods. The first is the one of the traction test, where the material is literally stretched while a special nib detector locates (tracing on a graph) the loads of yield, maximum load and breaking load. The second tests consist of hardness: Vickers, Rockwell and Brinell. From these tests one can recognize the different materials (more specifically the metals).

ROCKWELL

The Rockwell hardness test measures the depth gain of the footprint left by the penetrator, which can be a diamond cone with a 120 ° vertex angle or a sphere of 1/8 "diameter or 1/16" depending on the scale Chosen (there are 15, each marked with an uppercase letter of the alphabet), subjected to the action of the load after a prescribed preload for each scale. The Rockwell hardness number is obtained by difference between 100 and double the increase in the penetration depth in micrometers and obtained under standard conditions under an appropriate load.

ROCKWELL HARD TEST

Hardness test based on the penetration depth of a specific penetrator in the specimen under certain conditions.

 ROLLING MILL

Thick or generic sectional reduction plant.

ROUND

Finished product hot-rolled, forged or drawn, in circular section bars.

 SCOTCH BRITE

Surface finish obtained for light mechanical abrasion on the sheet, mainly starting from a cold rolled finish, finish 2B. Normally, we do not talk about roughness levels for this finish. To the touch is smooth as a 2B and you do not appreciate significant roughness variations before and after processing.

SEMI-WORKED STEEL

Steel products such as round bars, sheets, ect ...

SERVICE CENTER

An operator who buys the metals stocks and then resell them in different shapes than the original one.

SKIN PASS

Ferritic and austenitic stainless steel coils are often subjected to the final treatment of recrystallization to a subsequent cold rolling. The latter takes the name of skin pass (literally leather passage) and aims to make the surface compact, flat and polished, improving the material's characteristics from the perspective of subsequent surface finishing operations.

SLITTING (LONGITUDINAL CUTTING)

This machining allows longitudinally cutting steel strips to obtain "fringes" consisting of strips of lower width than the starting strip. The ribbon provided in coil veins carried by an easel and passes, after being crushed by a pair of cylinders, between pairs of sharp disks mounted between two trees, one upper and the other lower. In the valley, the narrower strips thus obtained are wound around the spiral on an ejector.

SNAPSHOT

Particular discontinuity in deformation of steels; In the stainless steel it is assumed that the unit load causes the deviation of 0.2% from the proportionality.

STAINLESS STEELS

They are ferrous alloys containing chromium by at least 10.5% with mechanical properties typical of carbon steels and having a strong corrosion resistance, especially in humid or fresh water and maintaining their high temperature hardness

STEEL

It is commonly known as an alloy of iron and carbon containing a carbon content not exceeding 2.1%

STEEL MILL

Industrial plant for cast iron manufacturing and steel production

SURFACE ROUGHNESS

The roughness for a generic material depends on surface irregularities. These irregularities are of a different nature, essentially due to the action of machine tools. The parameter Ra, whose unit of measurement is the micron, is the one most used and recognized by all world standards for measuring surface roughness.

TOLERANCE

Margin within which a value is acceptable (eg thickness tolerance).

TRACING TEST

A procedure by which the behavior of a metal subjected to a one-way deformation process is determined.

VICKERS HARD TEST

Try to determine the hardness of a material by using a square-based pyramid-shape diamond to which a certain load is applied. The result is expressed as a hardness number Vickers, obtained by dividing the applied load in kg for the surface of the impression obtained in mm 2.

 

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