Analogs: AISI 439 / 430Ti (USA); GOST 08x17T; EN 1.4510 (Europe); DIN X3CrTi17 (Germany).

Basic information

Stabilized titanium Nickel-free ferritic stainless steel grade AISI 439 is an improved analogue of 08KH17T (GOST 5632−72). Steel AISI 439 has corrosion resistance in most oxidizing environments (fresh water and boiling acids). Balanced chemical composition provides resistance to intergranular corrosion and high corrosion resistance.

The chemical composition of the AISI 439, in percent.

Relevance

The presence in the alloy of aluminum with titanium in conjunction with low carbon content, gives steel AISI 439 high plastic and strength properties (which are comparable to Nickel AISI 304) the higher the stability of the structure during welding or heating. It also combines the good plastic deformability (use in the processes of stamping, punching holes, etc.) and high strength properties. Steel AISI 439 is recommended as a substitute for steel 12KH18N9T and 12KH18N10T. Stabilization titanium structure and low carbon concentration ensures its excellent weldability, no tendency of welded joints to intergranular corrosion (sharp carbamoilirovaniem starts to occur only at t° more than 1000°C).The corrosion resistance of steel in most environments can be compared with the resistance of steels of the austenitic type AISI 304, 12X18H10T, etc. This steel is resistant against corrosion water, air (including high temperatures), as well as in solutions of most alkalis and many organic acids, carbon-containing organic compounds (including animal and plant origin) in nitric acid solution.

Another advantage is that in comparison with Nickel austenitic brands, this steel is not sensitive to intergranular corrosion in the temperature range 500−800°C, and is also much less sensitive under load to chloride cracking. When the load resistance to chloride cracking is ~ 350 MPa, and for steel 08KH18N10T (and other Nickel austenitic steels) this value is not higher than 150 MPa.

In the table the comparative characteristics of AISI 439 and 12X18H10T.

Characteristics of AISI 439

Compared to Nickel-containing austenitic steels of 18Cr-10Ni, ferritic stainless steels are resistant to sulfur-containing environments, thus, a pipe and other products from this steel can be used in systems pumping of oil, gas and clean petroleum products, hydrocarbons in process units of oil refining and gas processing. AISI 439 proven itself as a material resistant to gaseous media, which are formed in the combustion process. AISI 439 is used in the manufacture of pipes and liners recirculation systems, neutralization and exhaust trap exhaust gases. Sophisticated high-temperature catalytic oxidation-reduction reactions and corrosive gas environment to determine the application of corrosion-resistant economically-alloyed steel AISI 439 in the manufacture of exhaust systems, furnace and other related equipment (chimneys, exhaust ducts, etc.). Such environments typically contain products of incomplete combustion (hydrocarbons, carbon monoxide, oxides of nitrogen, hydrogen sulfide, sulfur dioxide, etc.) and complete combustion (water vapor, carbon dioxide, nitrogen, etc.).

Since chromium steels have a lower coefficient of thermal expansion and higher heat conductivity than austenitic, Nickel-containing steel, it determines the advantage of a chrome tubular steel products in heat exchange structures such as cooling gradeline. Low coefficient of thermal expansion provides the most reliable pittingale mount and rapid heat transfer in the cooling system food reservoirs (system with cooling water, glycol and other cooling media). Piping and welded construction of chromium steels resize, the temperature variation is much smaller, which reduces the fatigue rupture load from temperature change, preventing potential leaks from the various hydraulic connections.

Scope

AISI 439 can be used in the production of technological equipment that is used at various stages in food production (hygienic handling, washing of raw materials, equipment and products, separation and sorting of products, grinding, blending, packing and packaging, thermal processing, transportation, etc.). On the basis of multiple reference literature, ferritic steels such as AISI 439, can be applied in production machines and machine parts for the wine industry. Steel of this type permitted for use in direct contact with wine, wort, cognac alcohol, as well as by-products of winery wastes. Allowed the use of these steels (08KH17T) for production equipment of dairy and meat industry at temperatures of 30−140°C. All steel this series (400), including and AISI 439 can be not only applied as substitutes for Nickel-containing grades, but much better for some properties to be indispensable in the manufacture of food processing equipment. AISI 439 is fully consistent with the sanitary-epidemiological state standards and regulations and is very promising in the application in the production of equipment for processing and food industry: meat, fat, baking, alcohol, beer and soft drinks, confectionery, alcoholic beverage and others. High corrosion resistance of steel AISI 439 is due to the minimum percentage of carbon and high chromium content.

AISI 439 is widely used in such industries as:

-automotive;

-production of kitchen utensils, serving tools, tables, sinks, parts washing machines, sinks, pallets and drums for washing machines, etc.;

-equipment for heat exchangers;

-production of internal and external accessories;

-architecture and design;

-civil engineering;

-food industry. .

Use sparingly-alloyed Nickel-free stainless steels (ie analogues 430) in the processing and food industries regulated by standards and other normative documents.

Temporary resistance at high temperatures:

The properties of steel at high temperatures

AISI 439 is not hardened in the heat treatment process and has a good resistance to scale formation, while maintaining the beneficial mechanical properties to high temperatures. Steel AISI 439 is positioned as a heat-resistant, but the real operating temperature depends on the environmental conditions.

Welding

This steel is welded by all known methods, subject to the adoption of the post-weld passivation measures, etching/cleaning without losing corrosion properties in welding areas. For optimal use of arc welding in inert gases, you must comply with the minimum energy consumption during the welding of the seam. Recommended welding «on top» (i.e., if the work surface is located below the welding tool). In the form of filler material can be used austenitic wire SV-07CR25NI13, 309L, St-08Х25Н13БТЮ, etc. it is also possible to use electrodes or filler wire basis chromium ferritic steel AISI 439. To ensure adequate corrosion resistance should remove the dross, as well as the color of the tint by etching or mechanical treatment with brushes made of stainless steel and prepassivate with the help of cold solution (10−20%) nitric acid. The next step is a thorough rinsing in cold water and drying.

Buy at best price

The company «AVEK global» sells a range of products from steel AISI 439. The popularity of this type of products due high quality products, great variety and real value. Every our products undergoes strict control throughout the production chain, to guarantee absolute high quality of our steel products. Modern technological capabilities at any stage of production provide the opportunity to carry out individual orders in the absence of a required item in the basic version. The company «AVEK global» is always ready to produce quality products according to individual order.