Chrome in heat-resistant steel
Are you interested in the characteristics of chromium in stainless steels from the supplier company AvecGlob? Here you will find the necessary information on this topic.
General information
Most brands of stainless steels contain between 10 and 30% chromium. The addition of chromium to steel compositions leads to the formation of a stable surface film of chromium oxide, and the stability of such a film increases with increasing chromium content. This oxide film provides corrosion resistance and is the basis on which the basic properties of stainless steel are built.
Ferritic stainless steels
Low-carbon steels containing from 12 to 30% chromium are ferritic stainless steels that are not subjected to heat treatment. The increase in mechanical properties can be achieved only with cold working. Corrosion resistance of this group is much better than high-carbon high-chromium steels.
Martensitic stainless steels
High-carbon, high-chromium steels are heat-treated and are known as martensitic stainless steels. However, they exhibit a lower corrosion resistance due to depletion of the chromium oxide film. They have good strength and oxidation resistance up to 750 ° C, although their creep strength above 600 ° C does not always satisfy production.
Austenitic stainless steels
Austenitic stainless steels result from the addition of nickel (typically 10 to 20%) to low-carbon steels containing 18 to 25% chromium. These steels have excellent corrosion resistance in a wide range of media.
Properties can only be changed by cold plastic deformation. They are also much more expensive than high-chromium steels. The steels are nonmagnetic, have average values of the coefficient of thermal expansion and small values of thermal conductivity.
Supplier — the company AvekGlob — offers to buy in the range of metal, made of different grades of chromium-containing stainless steels. Products can be bought at a price formed on the basis of European and world standards. Implementation is possible in bulk and retail, for regular customers, a flexible system of discounts operates.
Influence of heat treatment and structure
Galvanized stainless steels are chromium-nickel alloys containing hardening elements, such as copper, aluminum or titanium. Alloys have two general types: semi-austenitic, requiring double heat treatment to achieve final strength properties and martensitic, requiring a single heat treatment to achieve ultimate strength properties. The main advantage of these alloys is low-temperature heat treatment, which is necessary to achieve ultimate strength, which can reach 2 GPa, which leads to minimal distortion of the shape.
It should be noted that chromium tends to migrate to grain boundaries at elevated temperatures, where it forms chromium carbide. This is a serious problem in areas exposed to heat from welds.
This effect is known as «weld breakdown» and causes fracture due to corrosion along grain boundaries where chromium depletion occurs. For welding, the carbon content is <0.03%, in order to avoid significant carbide formation. On the other hand,
steel can be «stabilized» with the addition of titanium or niobium, which form carbides preferred for chromium.
Although stainless steels containing a lot of chromium are more corrosion-resistant than other steels, they are subject to specific corrosion mechanisms, such as weld failure.
Supplier — AvekGlob Company — offers various types of rolled products from stainless chromium-containing steels of domestic and foreign production. Products are offered at affordable prices from the manufacturer. The supplier guarantees the timely delivery of products to any address specified by the consumer.