Relevance

To improve the corrosion resistance, strength and technological properties in the composition of metals introduced a variety of alloying elements. Vanadium, tungsten, manganese, nickel, niobium, titanium, chromium and others are used to alloy steels. Zinc additives to copper and bronze increase strength, ductility, corrosion resistance Small additives of cadmium to copper increase wear resistance of wires. When alloying titanium with molybdenum the operating temperature limit of the alloy doubles due to the change in its crystal structure. Alloying involves the introduction of one or more elements that give alloys unique properties.

Structural steels

The alloying of structural steel greatly increases its strength. The main constituent in structural steel is ferrite. It makes up 90% of the alloy structure. The alloying elements dissolve in the ferrite and harden the structure. Silicon, manganese and nickel increase the hardness of the alloy more than others. Molybdenum, tungsten and chromium have a weaker effect. Most alloying elements, while strengthening the structure and having little effect on ductility, reduce toughness (except for nickel).

How the hardening process works

Alloying hardens ferrite. Alloying elements increase hardness, strength and toughness, increase austenite stability, hardenability, etc. For example, for steels that are used in turbines, boilers , etc., corrosion resistance and heat resistance are of particular importance. The alloying elements can dissolve in ferrite or austenite, form carbides, form intermetallic compounds or be arranged as inclusions that do not interact with ferrite and austenite or carbon.

Ferritic steel

Depending on the way the alloying additives interact with iron or carbon, the properties of steel are determined. Ferrite can dissolve all elements to a greater or lesser degree. The dissolution of the alloying additives in ferrite enables the steel to be hardened without heat treatment. This increases the tensile strength and hardness, but the toughness is usually reduced. All elements that dissolve in iron affect the stability of austenite and ferrite. The critical points of alloyed steels are shifted by the quantity and quality of the alloying additives. Therefore, the choice of hardening, normalizing, annealing and tempering regimes should take into account the shifting of critical points.

Mn and Si.

They are technological impurities and are introduced into the steel smelting process for deoxidation. The proportion of Mn in steel is up to 2%. It is distributed between cementite and ferrite and greatly increases the cold brittleness threshold, hardenability, and yield strength, but makes the steel sensitive to overheating. Therefore, carbide-forming elements are introduced into the alloy along with manganese to refine the grain. Since all steels have about the same manganese content, its effect on changing the properties of steel of different composition is insignificant. It increases steel strength without changing ductility.

Steel deoxidation

Mn and Si are found in virtually every steel. Silicon, along with manganese and aluminum, is a major deoxidizer. Mn is also needed to "bind" the sulfur in the steel and eliminate brittleness. Additions of these elements usually do not exceed 0.17 to 0.37% Si, 0.3 to 0.7% Mn and about 0.03% Al. Within these limits they are considered process impurities and are not alloying elements. Specific additions above that level, in order to give the steel certain properties, are considered to be alloying.

Silicon

Silicon is not a carbide forming element, and its proportion in steel is usually less than 2%. It greatly increases the yield strength and toughness of steel, and at levels above 1%, it reduces ductility, ductility and increases the cold-brittleness threshold. Silicon is not structurally detected, as it is usually dissolved in ferrite, except for the part of the silicon that in the form of oxide did not have time to float in the slag and remained in the metal in the form of inclusions.

Buy, price

Evek GmbH stocks a wide range of high quality rolled steel in standard and non-standard sizes. We supply products of alloyed alloys in retail and wholesale. All products are certified for compliance with standards and operating conditions. The certificate indicates the manufacturer, drawing number and product name, alloy grade, melting number, details, chemical composition, mechanical properties and the results of additional tests. Implementation of orders - in the shortest possible time. Preferential discounts are offered to wholesale customers.