One of the most common and used among stainless materials is steel grade 12X18n10t. The characteristics of the alloy, which we will consider in today's article, have contributed to this to a large extent. If we describe the membership of this composition in full, then we must definitely emphasize that it contains titanium, but belongs to the austenitic class.
General description of key parameters
So, we can start with the fact that the chemical composition of steel is regulated by the rather old GOST 5632-72. Among the unique advantages of this type of material, high impact strength and high ductility stand out. Since the alloy brand belongs to the austenitic class, naturally, it undergoes heat treatment. This procedure consists in the hardening process at a temperature of 1050 to 1080 degrees Celsius, followed by cooling of the material in water. Carrying out this procedure ensures the achievement of maximum viscosity and ductility. Strength as well as hardness of the material will be approximately at the average level.
Another important point is that when working with temperatures up to +600 degrees Celsius, the characteristics of 12x18n10t allow the alloy to be used as heat-resistant. The main alloying elements used are chromium and nickel.
Another important property is that single-phase alloys have a stable structure of the austenitic class with a small amount of titanium carbides. This substance is added in order to avoid such a disadvantage as intergranular corrosion. The strength level of steels belonging to the austenitic and austenitic-ferritic classes does not exceed the limit of 700-850 MPa.
Steel use
Alloy 12x18n10t, which can also be called stainless chromium-nickel steel, can be used in a wide variety of fields. For example, such a composition with varying degrees of strength is successfully used where it is necessary to combine high strength and elastic properties of metal parts operating in an aggressive environment.
Consumer properties
If we talk about the main consumer properties of this alloy, it is important to note the following. Such 12x18n10t characteristics as tensile strength, as well as elongation, are established with a certain degree of approximation. There are also reference data that does not take into account the hardenability of the metal, which significantly depends on the chemical composition, melting method, and those parameters that were before processing.
Specialists recommend using this steel in cases where it is necessary to make welded parts in dilute solutions of various acids (nitric, phosphoric, etc.). It is also possible to produce a variety of parts that can work in the temperature range from -196 to +600 degrees Celsius under high pressure. It is worth noting here that if there is a close relationship with any aggressive environment, then the upper temperature limit will drop from 600 to 350 degrees.
Characteristics 12h18n10t. Labeling Explanation
So, if we talk about the decoding of this class, then, naturally, we should start with general concepts. The first thing that can be seen in the name is the numbers. This value shows what the average carbon content is in hundredths of a percent in this composition. Speaking specifically about this alloy, here this content will be 0.12%. If, for example, only one digit is indicated at the beginning, this means that the amount of carbon rises to tenths of a percent. If the figure is completely absent, then this substance in the material is 1% or more.
Next, consider the letter X and the number 18 together. The letter indicates that the composition contains chrome, and the number shows how much it is in percent. In this case, the Cr content is 18%. It is important to note here that there can only be carbon in hundredths or tenths of a percent, and such figures are only at the beginning. All other characteristics of steel 12x18n10t are indicated in full percent.
Then everything becomes simpler, n10 indicates that the composition contains 10% nickel. As for the last letter T, it indicates the titanium content in the alloy. The figure here is apparently absent, which means that the amount is quite small - about 1%. The titanium content cannot exceed 1.5% of the total mass fraction.
To summarize, the characteristic of steel 12x18n10t is as follows: 0.12% carbon, 18% chromium, 10% nickel, a small amount of titanium, which does not exceed the rate of 1.5%. All this can be learned only from the name.
How do alloying elements alter the structure of the alloy?
Naturally, each of the elements that are added to the composition has its own effect on the final characteristics of a 12x18n10t stainless steel.
For example, nickel. Using this element as an alloying element increases the g - region. However, it is very important to note that there should be a sufficient amount of it - from 8 to 12% in order to get the expansion effect. Another important fact - the addition of this particular substance transfers the alloy into the austenitic class, and this is key. The transition to this class allows you to combine a very high technological steel and a large number of diverse operational characteristics. The addition of nickel increases the resistance to corrosion and allows the use of steel in those places where there is constant contact with aggressive media (acids).
Strength characteristics of Art. 12x18n10t
One of the most common methods for increasing strength is considered to be high temperature heat treatment (HTMO). In order to study the effect of HTMC on this type of steel, we selected billets of 100 x 100 mm and a length of 2.5 to 5 m. Quenching was carried out at mill 350. The process looked like this: first, the raw materials were heated in a methodical furnace at a temperature of 1150- 1200 degrees. Then they were kept under the influence of the same temperature for 2-3 hours. The steel itself was rolled using conventional rolling technology.
It can be added that steel 12x18n10t hardens harder than, for example, 08x18n10t, but at the same time its percentage of softening is increased with increasing temperature. This is due to a different proportion of carbon content.
What else is important to say about the temperature characteristics is that if the steel is operated at an indicator of 800 degrees, then the maximum time of its operation is about 10,000 hours.