Seamed tubes

They are produced with longitudinal welding, with or without the addition of metal, meeting the requirements of technical standards, such as: ASTM A-269 / A-312 / A-249 / A-270 / A-554 / A-778 / A- 358.

Seamless tubes

They are imported and can be produced according to different processes, depending on the need. Due to the demanding quality process, Carbinox only imports products from manufacturers that meet the requirements of technical standards, such as: ASTM A-213 / A-269 / A-312.
Main segments: Food, Chemical, Petrochemical, Textile, Pharmaceutical, Pulp and Paper, Sugar and Alcohol, Boilermaking, etc.

AISI 303
Easy to machine material, used in the production of parts on automatic lathes.

AISI 304
Alloy with the greatest application within Stainless Steel, present in equipment in the food, chemical, petrochemical, textile, pharmaceutical, paper and pulp, furniture, structural, alcohol, cryogenic, boilermaking industries, etc.

AISI 304L
Same as AISI 304, but with extra low Carbon content, applied when the project foresees welding or other conditions that subject the alloy to the range of 450ºC to 900ºC, thus avoiding intergranular corrosion.

AISI 316
Same as AISI 304, however, due to the addition of Molybdenum, this alloy is used in more severe corrosive conditions.

AISI 316L
Same as AISI 316, but with extra low Carbon content, for the reasons presented for AISI 304L.

AISI 316Ti
Same as AISI 316L, but using Titanium as a protective factor against intergranular corrosion.

AISI 321
Same as AISI 304L, but using Titanium as a protective factor against intergranular corrosion.

AISI 347
Same as AISI 321, but using Niobium as a protective factor against intergranular corrosion.

AISI 310S
Applied in high temperature situations such as furnace parts and components, turbine components, heaters and heat exchangers.

AISI 317
Applied in industries in general, in particular in paper and pulp, brines and other applications where the AISI 316 alloy does not have sufficient corrosion resistance

AISI 317L
Same as AISI 317, but containing extra low Carbon content, for the reasons presented for AISI 304L.

AISI 446
Tubes for applications above 700°C (1290°F). Heat recovery units, thermocouple protection, sootblowers.

AISI 904L
Applied in severe corrosive conditions such as in the production and handling of strong acids such as sulfuric and phosphoric. It is also an excellent choice for heat exchangers that use seawater as a cooling way, as well as in processes with high chloride levels.

Stainless Steels, despite having a Chromium oxide film that protects them against external environment, can be subject to attacks due to inadequate selection of the material in relation to the environment’s application.

Initially, attacks are divided into wet corrosion and high temperature corrosion.

Corrosion in Wet Way
The main wet mechanisms that can occur in stainless steels are general corrosion, pitting corrosion, crevice corrosion, intergranular corrosion, fracture stress corrosion, galvanic pair corrosion and erosion corrosion.

General corrosion
It is characterized by the uniform loss of thickness from the surface of the material which is in contact with the corrosive environment. Increased levels of Chromium, Nickel and Molybdenum, as well as the addition of Copper, increase resistance to corrosion in general.

Pitting Corrosion
Also known as localized or punctiform corrosion, it is characterized by punctual attack in a limited area, but with significant depth. Additions of Cr, Mo and N increase resistance to pitting corrosion.

Crevice corrosion
This is also a localized attack, which occurs in small, narrow spaces due to inadequate design. As with pitting corrosion, additions of Cr, Mo and N increase resistance to crevice corrosion.

Intergranular corrosion
Caused by the precipitation of chromium carbides at the grain boundaries, causing dechromization of regions adjacent to the boundaries. Such regions no longer present passive film, making them susceptible to attacks. The phenomenon is avoided by using “L” alloys, which have extra-low C contents (below 0.035%) or by using Ti, Nb or Ta stabilized materials.

Fracturing Tension Corrosion
Characterized by the association of three combined factors: residual tensions in the material, medium containing chlorides and temperature above 60ºC. From a localized attack, CSTF is evidenced by the appearance of radial cracks that quickly propagate. Materials with a high Ni content, as well as Duplex stainless steels, appear as a solution to combat CSTF.

Galvanic Pair Corrosion
A phenomenon characterized by contact between two metals with different electrical potentials, subjected to the same electrolyte. Such contact should be avoided

Corrosion-Erosion
Deterioration mechanisms of stainless steels when they are simultaneously subjected to a corrosive environment and a mechanical wear process. The passive film is continuously under abrasive and corrosive effects at the same time. Duplex stainless steels are an excellent option for resistance to corrosion-erosion

High Temperature Corrosion
Also called dry corrosion phenomena, it is characterized by the attack resulting from the interaction between a metallic material and a corrosive environment, both subjected to high temperatures. They normally occur in conditions known as air, in combustion gases, slag, corrosive ash, metals and molten salts.

In air
When metallic materials are heated in air, an oxygen film is formed on their surface. Up to a certain temperature, known as scaling temperature, the oxide layer is dense and adherent, protecting the metal alloy against further attack.

When this temperature is exceeded, the oxide layer breaks and detaches from the surface of the material, thus losing its protective capacity.

By increasing the content of Cr and Ni, as well as adding Si and Al, the scaling temperatures become higher.

Combustion gases
The maximum working temperature is sharply reduced by the presence of impurities in the atmosphere, particularly sulphurous gases.

Slag and Corrosive Ash
Such particulates are aggressive to stainless steels, being formed by silicates, sulfates and oxides in general, which attack forming eutectics with a low melting point.

Molten Metals and Molten Salts
The corrosive environment in question acts on the surface of stainless steels, also forming eutectics with a low melting point.

Effects of Alloy Elements on Stainless Steels

Chromium
Main alloying element in stainless steels, as it is responsible for the appearance of the passive film (CrxOY), when its content is greater than 12%. The higher the Cr content, the greater the corrosion resistance.

Nickel
The second most important element in stainless steels. Stabilizes austenite at room temperature, promoting corrosion resistance and enhancing the workability of stainless steels.

Molybdenum
Additions of Mo increase resistance to general corrosion, pitting and crevice corrosion in stainless steels.

Carbon
Low levels of C, in the order of 0.03%, provide greater resistance to corrosion in stainless steels. Due to the high affinity of C with Cr at high temperatures, stainless steels with extra-low C levels are normally used when, for example, they are subject to welding. This procedure inhibits the intergranular corrosion process in stainless steels. On the other hand, higher levels of C contribute to high-temperature applications of stainless steels. From 0.15% C, stainless steels become hardenable.

Titanium, Niobium and Tantalum
Elements added to stainless steels because they have a greater affinity with C, thus preventing the precipitation and formation of chromium carbides. In this way, they increase resistance to intergranular corrosion

Sulfur
Although normally undesirable, it can be added to stainless steels in order to improve their machinability.

Nitrogen
Added to Austenitic and Duplex stainless steels, with the aim of enhancing corrosion resistance and mechanical properties

Copper
Additions of Cu enhance general corrosion resistance in aggressive environments containing, for example, phosphoric or sulfuric acid.

Aluminum
Increases resistance to oxidation at high temperatures