The properties and microstructure of stainless steel

Nov 30 08:20 2012 David Yvon Print This Article

Performance and organizational formation of stainless steel is mainly determined by various elements. Currently, there are a hundred kinds of known chemical elements, maximum elements influence the performance of the stainless steel and organizational have: carbon, chromium, nickel, manganese, nitrogen, titanium, niobium, molybdenum, copper, aluminum, silicon, vanadium, tungsten, boron and others. 

Because of adding these elements,Guest Posting resulting in the change of the internal organization of the steel, so that make the steel have special properties.

High-chromium ferritic stainless steel was added 0.005% of boron powder, can make the corrosion resistance of steel in boiling 65% acetic acid be improved; added trace (0.0006 to 0.0007%) of boron in the austenitic stainless steel can make heatstate plasticity be improved; boron to improve the hot strength of steel have good effect, make the hot strength of stainless steel be significantly improved; boron chromium-nickel austenitic stainless steel has a special use in the atomic energy industry. but the stainless steel containing boron will cause reduced ductility and toughness.

According to metal powder supplier, a lot of steels exist several or even more alloying elements, When several elements coexist on the stainless steel this continuum, decided stainless organization is the sum of the influence of various elements. Various elements impact on the organization of stainless steel, according to its commonality, to sum up, basically belong to two categories: one is the formation of stable austenite elements, they are carbon, nickel, manganese, nitrogen, copper, the role of carbon and nitrogen is the greatest; the other is formed of the ferrite element, which is a chromium, tungsten, molybdenum, niobium, silicon, titanium, vanadium, aluminum or the like, this type elements form ferrite, such as chromium is to be compared, the role of the other elements were larger than the chromium. The coexistence of these two types of elements in stainless steel, stainless steel tissue depending on the results they influence each other. If the stable austenite elements role residing in the main aspects, the organization of stainless austenitic-based, rarely even no ferrite; if their role is not yet make austenite at room temperature maintained until then, this unstable austenite upon cooling, martensite transformation occurs, and the steel tissue is martensite; if the ferrite element is formed into the main aspects, steel tissue is mainly in ferrolites. Performance of the stainless steel except for process factors, mainly depends on the composition of its internal organization, and is the sum of the various alloy elements in the steel constituting the stainless steel tissue. Therefore, the performance of stainless steel, in the final analysis, is mainly determined by the alloy elements.

Adding the right amount of nickel in the chromium grade stainless steel matrix elements. Such as in the ferritic steels of the chromium-containing 18% of the low-carbon (0.12% or less of carbon) adding 8% nickel, the ideal pure austenite structure is obtained at room temperature, this steel is that people generally said non-magnetic stainless steel. Chromium-nickel stainless steel such as the same amount of chromium ferritic or martensitic acidproof stainless steel comparison, not only has a higher corrosion resistance, and more important to mention that they have a good cold deformation so that hardening and welding properties, in ambient temperature or low temperature with high plasticity and toughness, and excellent performance of the non-magnetic, etc.. The disadvantage of this type of stainless steel is low mechanical properties, sensitive to intergranular corrosion and stress corrosion, but by the right amount of alloy additives or process measures can improve or eliminate.

Source:http://www.mhcmp.com

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