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.


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.

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

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

More items from cnwellgreen

What Is Stainless Steel Solution Annealing?

Austenitic stainless steels are softened by solution annealing . Generally, stainless steel pipe and fittings are heated to 950 to 1150 degrees Celsius and held for a period of time. The purpose of this is to make the carbides and various alloying elements sufficiently uniformly dissol ...

roger chen - kaysuns industry limited

Posted 3 days agoPress > stainless steelSolution Annealing

Advantages Of Duplex 2205 Pipe Over Oil Industry

Why Duplex Pipe Be Used In Oil Industry Compared with 316L and 317L stainless steels, 2205 duplex stainless steel has better performance in pitting and crevice corrosion resistance.It has high corrosion resistance and a lower coefficient of thermal expansion than austenite Higher thermal conductiv ...

roger chen - kaysuns industry limited

Posted 1 month agoPress > oil industryduplex pipeduplex 2205 pipe +1

Manufacturing Process of Duplex Pipe - Why Duplex Pipe is Expensive

Manufacturing Process of Duplex Pipe - Why Duplex Pipe is Expensive After more than ten years of development, the manufacturing process of duplex stainless steel pipes has gradually matured, it made the material from high-end to ordinary applications. Considering the relative cost, more and more c ...

roger chen - kaysuns industry limited

Posted 1 month agoPress > Manufacturing Processduplex pipeWhy Duplex Pipe is Expensive +1

IMO 2020 and Scrubber

In the coming 2020, the sulfur-limiting order formulated by the International Maritime Organization (IMO 2020) will bring a series of changes to shipping. According to the latest estimates by the Exhaust Gas Cleaning Systems Association (EGCSA), at least 4,000 ships will be equipped with scrubbers ...

roger chen - kaysuns industry limited

Posted 2 months agoPress > IMO 2020Exhaust Gas Cleaning Systems AssociationInternational Maritime Organization

Annual Output Value Reaches 10 Billion! Guangdong Yongjin's Stainless Steel Phase I Has Been Completed 90%, Trial Production Next Month!

We carry out the cold rolling process independently, all relying on the upstream raw material support. Here in Yangjiang city, we must rely on the supply of Guangqing's raw materials. Its raw material guarantee has great support for the supply of our customers. After the first phase of the project ...

roger chen - kaysuns industry limited

Posted 2 months agoPress > cold rolling processstainless steelYongjin inc. +1
All posts from cnwellgreen