Bilbao - 94 467 11 60 / Madrid 91 871 16 90 / Sevilla 954 196 223 bilbao@alinox.es

SURFACE FINISHES

We perform different finishes on stainless steel sheet depending on the application.

We cover in this way the needs of different sectors in general and particularly customer needs

Finishes by rolling and by abrasion

STAINLESS STEEL APPLICATIONS

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AUSTENITIC STAINLESS STEEL

It is the most commonly used throughout the series. It combines excellent mechanical characteristics with a high resistance to corrosion between -263ºC and 560 ° C. It is primarily used in the chemical industry in general, food, refineries, dairy industry etc.

(18-8 con CO 0.030%)

When the material 304 is worked at temperatures between 400 and 900º, carbon tends to combine with chromium, leading to formation of chromium carbides which significantly reduce the strength of the material (intergranular corrosion). 304 L as the lower carbon content has a much lower tendency to intergranular corrosion.
This is very important if after welding or hot work there is no possibility of annealing treatment.
Although the corrosion resistance is superior to steel 304, its mechanical properties are lower, which implies the use of higher thicknesses. It is not appropriate to use for systems whose service temperature is very high.

(18-8 ESTABILIZADO WITH TITANIUM)

Based on the 304, the additions of titanium stabilize steel, which prevents the carbon is combined with chromium to form chromium carbides in critical temperatures titanium carbides completely harmless. With the same resistance that 304, it adds a higher mechanical characteristics. It is particularly recommended for uses requiring long periods of temperatures between 500-800ºC, as superheated tubes, radiant tubes, furnaces cracking

(18-8 CON 2% OF MOLYBDENUM)

Molybdenum addiction fundamentally improves its resistance to violent corrosives (acids, salt atmospheres …). Mainly used in industries such as textiles, synthetic fibers, detergents, urea, saline environments, sulfuric acid, cellulose. It has high corrosion resistance and good mechanical strength up to 900 ° C

Commonly known as “refractory steel 25-20”, it has exceptional qualities due to its high content of CrNi. The corrosion resistance and oxidation are high and can be used in continuous service even 1050. (components in furnaces, heat exchangers …)

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MARTENSITIC STAINLESS STEEL

Tempered martensitic steel. Resistant to the 659º in continuous service but its corrosion resistance is less than ordinary 304 due to its carbon content. Excellent resistance for uses in contact with water, steam, weak chemical agents, etc.

Martensitic steel can get by hardness and tempering very high mechanical properties, it has good corrosion resistance

CORROSION RESISTANCE

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TYPES OF CORROSION

The pitting resistance is primarily important in applications where chlorides present solutions and particularly in the presence of oxidizing environments. These conditions can lead to a localized presentation of the passive surface film on steel and a unique and deep bite can easily be more damaging than a much larger number of relatively shallow bites.Where pitting corrosion is anticipated, it is recommended to use steels with a molybdenum content that will give a better result than other rankings.

The atmospheric corrosion resistance of austenitic stainless steels has virtually unrivaled among engineering materials without surface coating. Stainless steel has high corrosion resistance and surface pitting when molybdenum is added.For this reason, it is common practice to use the graduation 316 containing molybdenum, because in many areas the atmosphere is contaminated with sulfur chlorides and other substances, either alone or in combination.

However there are many urban and rural areas where the graduation 304 is perfectly satisfactory.

 

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EVALUATION OF CORROSION

In the evaluation tables of corrosion is determined as follows:

A)Excellent resistance: weight loss lower 25mg / dm2 (24h)

B)Generally acceptable resistance: weight loss of less than 250 mg / dm 2 (24h)

C)Mediocre or poor resistance: weight loss greater than 250 mg / dm 2 (24h)

 

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