A: the varieties of stainless steel: stainless steel can according to the use, chemical composition and metallographic arrangements to general classification.
In austenite steel by 18% chromium - system class
8% nickel as the basic form, is not the same as the amount of each element to change, and the development of all kinds of useful material.
By chemical composition: (1) CR series: series of ferrite, column 2) CR - markov system
NI series: column austenite system, abnormal series, hardening of the series.
To the classification of the metallographic arrangement: (1) the austenitic stainless steel (2) ferritic stainless steel (3) martensitic stainless steel (4) duplex stainless steel (5 sedimentary hardening stainless steel 2: the use of stainless steel, austenitic -
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Ferrite: duplex stainless steel is to arrange the austenite and ferrite accounts for about half of the stainless steel.
In the case of contain low C, Cr content was 18% ~ 28%, Ni content at 3% ~ 10%.
Some steel also rich in Mo, Cu, Si, Nb, Ti, N and other alloying elements.
This kind of steel both austenite and ferrite stainless steel features, compared with ferrite, plastic, patience is higher, there is no room temperature brittleness, intergranular corrosion resistance and welding functions are significant progress, but also maintain a ferritic stainless steel of 475 ℃ brittleness and high thermal conductivity, has the characteristics such as superplasticity.
Compared with austenitic stainless steel, high strength and resistance to intergranular corrosion and resistance to chloride stress corrosion have significant progress.
Duplex stainless steel has excellent resistance to pitting corrosion function, also is a kind of nickel and stainless steel.
Austenitic stainless steel: arranged with austenitic stainless steel at room temperature.
Contains about 18% of Cr, Ni in steel by 8% ~ 10%, about 0 C.
1%, has the stable austenite arrangement.
Austenitic chromium nickel stainless steel containing 18 cr - known
8 Ni steel and on this basis, increase the content of Cr, Ni and participate in Mo, Cu, Si, Nb, Ti and other elements of high Cr -
Ni steel series.
Austenitic stainless steel nonmagnetic and high patience and plastic, but strength is low, can't after phase transformation strengthening, only after a cold working to strengthen.
Such as S, Ca, Se, Te elements, such as has outstanding free-cutting sex.
This kind of steel in addition to the acid medium corrosion resistance to oxidation, if rich in Mo, Cu element also ability such as sulfuric acid, phosphoric acid and the corrosion of formic acid, acetic acid, urea, etc.
If the carbon content of steel is lower than 0.
Should be 03% or containing Ti, Ni, significant progress in its intergranular corrosion resistant function.
High silicon austenitic stainless steel nitric acid has excellent corrosion resistance.
Because the austenitic stainless steel has comprehensive and outstanding inductive function, obtained widely used in all walks of life.
Ferritic stainless steel: in the condition of using arranged in ferritic stainless steel.
Chromium content in 11% ~ 30%, with a body centered cubic crystal structure.
This kind of steel usually do not contain nickel, sometimes also contain a few Mo, Ti, Nb and elements, this kind of steel with heat conduction coefficient is big, small expansion coefficient, good oxidation resistance, resistance to stress corrosion excellent characteristics, such as used in the manufacture of air, water vapor and water resistant and oxidizing acid corrosion parts.
This kind of steel are low plasticity, plastic after welding, and corrosion resistance such as well as disadvantages, thus to restrain the use of it.
Outside the furnace is pithy skills (
AOD and VOD)
Apply can make the gap element such as carbon, nitrogen, dramatically reduced, so that this kind of steel is widely used.
Martensitic stainless steel, after heat treatment can adjust its mechanical function of stainless steel, easy to say, is a kind of stainless steel can be hardened.
Typical brand for Cr13 type, such as 2 Cr13 and 3 Cr13, 4 Cr13, etc.
After quench hardness is higher, is not the same as the different tempering temperature have strong patience, is mainly used for steam turbine blades, tableware, surgical instruments.
According to the difference between chemical composition, martensite stainless steel can be divided into martensite chromium steel and nickel chromium martensitic steel two kinds.
According to the arrangement and the mechanism of strengthening is different, also can be divided into martensite stainless steel, martensite and austenite (
Or a martensite)
Sedimentary hardened stainless steel and maraging stainless steel, etc.
A: on the bearing level of accuracy and next up: the performance of the bearing material should possess
