Press

Advantages And Disadvantages Of Adding Titanium In Austenitic Stainless Steel


Advantages And Disadvantages Of Adding Titanium In Austenitic Stainless Steel

When chromium-nickel austenitic stainless steel is heated to a temperature range of 450-800 ° C, intergranular corrosion often occurs, but the addition of titanium will improve this situation, but is this good or bad?

Intergranular corrosion is actually caused by the precipitation of carbon from the saturated austenitic metallurgical structure in the form of Cr23C6, which causes the austenite structure at the grain boundary to be depleted in chromium. Therefore, avoiding chromium deficiency at the grain boundary is an effective way to prevent intergranular corrosion.

The elements in the stainless steel are ordered according to the degree of carbon affinity, in the order of titanium, tantalum, molybdenum, chromium and manganese. It can be seen that the affinity of titanium and carbon is greater than that of chromium. When titanium is added to steel, carbon preferentially combines with titanium to form titanium carbide, which can effectively prevent the formation of chromium carbide and precipitation to form a grain boundary which is poor in chromium. Can effectively prevent intergranular corrosion.

Since titanium and nitrogen can combine to form titanium nitride, titanium and oxygen can be combined to form titanium dioxide, so the amount of titanium added is limited. In order to avoid intergranular corrosion in actual stainless steel production, the amount of titanium added is mainly about 0.8%.

In order to avoid intergranular corrosion, the titanium-containing stainless steel must be stabilized after solution treatment. After the solution treatment, the austenitic stainless steel obtains a single-phase austenite structure, but the state of this structure is not stable. When the temperature is raised to more than 450 ° C, the carbon in the solid solution gradually precipitates in the form of carbide, of which Cr23C6 The formation temperature is 650 ° C, and 900 ° C is the TiC formation temperature. To avoid intergranular corrosion, it is necessary to reduce the Cr23C6 content and allow the carbide to exist completely in the form of TiC.

TiC

Since the carbide stability of titanium is higher than that of chromium, when the stainless steel is heated above 700 ° C, the carbide of chromium begins to transform into the carbide of titanium. Stabilization is to heat the stainless steel to 850-930 ° C for 1 hour. At this time, the chromium carbide will completely decompose to form stable gray or black titanium carbide, and the resistance of the stainless steel to intergranular corrosion is optimized. In addition, titanium is added to the stainless steel to precipitate Fe2Ti intermetallic compounds under certain conditions to improve the high temperature strength of the stainless steel.

Disadvantages:
Titanium is also not completely harmless in stainless steel, and sometimes titanium can also jeopardize the performance of stainless steel. For example, there are easily inclusions such as TiO2 and TiN, and their content is high and unevenly distributed, which reduces the purity of stainless steel to some extent; it also makes the surface quality of stainless steel ingots worse, resulting in an increase in the amount of process grinding, which is easy. It causes waste; the polishing performance of the finished product is not very good, and the processing of high-precision surfaces is very difficult.

The article edited by duplex 2205 pipe kaysuns



New service from OilVoice
Trip Shepherd is for companies who need to track their staff in areas of risk.
It's free to use, so we invite you to try it.

Visit source site

https://kaysuns.com/advantages-and-disadvantages-o...

austenitic stainless steelduplex 2205 pipeduplex fittingsduplex pipeTitanium in stainless steelstainless steel knowledge

More items from cnwellgreen


Alkaline & Acid Corrosion Resistance Of 2205 Stainless Steel Pipe

In order to illustrate the Acid corrosion resistance of 2205 stainless steel in strong acid solutions, Figure 1 shows the corrosion data of sulfuric acid solution. Figure 1 The medium conditions range from a weakly reducing environment with low acid concentration to a high-concentrati ...

roger chen - kaysuns industry limited


Posted 10 days agoPress > 2205 Stainless Steel PipeAcid Corrosion ResistanceSandvik

What Are The Main Factors Affecting The Chemical Heat Treatment Of Duplex 2507

The chemical heat treatment of Duplex 2507 stainless steel   Duplex 2507, one of famous stainless steel matrials used in Petrochemical field. Chemical heat treatment of Duplex 2507 is mainly the formation of active atoms: the active atoms are absorbed by the metal surface and the active at ...

roger chen - kaysuns industry limited


Posted 1 month agoPress > Duplex 2507Petrochemical Industry

JISCO's Duplex Steel of Petroleum Makes Another Great Achievement: Enters The High-end Field

A few days ago, along with the successful downhole operation of corrosion-resistant alloy coiled 2205 stainless steel pipes in the Changqing Oilfield of China National Petroleum Corporation, it marked the entry of JISCO 2205 duplex steel of petroleum into the high-end field. Corrosion is a ...

roger chen - kaysuns industry limited


Posted 1 month agoPress > duplex steelJISCOPetroleum tubing

90 Years Of Development History Of Duplex Stainless Steel

2020 is the 90th anniversary history of duplex stainless steel Avesta Ironworks in 1930, located in Avesta, Sweden 1930s to 1970s In the early 1900s history of duplex stainless steel, the earliest stainless steels were pure austenite, ferrite or martensite. In 1930, Sweden's A ...

roger chen - kaysuns industry limited


Posted 2 months agoPress > duplex stainless steelDevelopment History

Tsingtuo Group's Bar and Wire Project Will Be Put Into Operation In September 2021

Tsingtuo Group's Stainless Steel Bar and Wire Project Will Be Put Into Operation In September 2021 Recently, the Fujian Provincial Development and Reform Commission issued the review opinions on the energy-saving review of the stainless steel bar and wire processing project of Fujian Tsingtu ...

roger chen - kaysuns industry limited


Posted 2 months agoPress > Stainless Steel BarTsingtuo GroupTsingshan Group
All posts from cnwellgreen