Circle, pipe, wire of AISI 439, EI645 steel

Technical Characteristics

Titanium-stabilized stainless nickel-free ferritic steel grade AISI 439 is an improved analogue of 08Cr17T (GOST 5632-72). Analogues: AISI 439 / 430Ti (USA); GOST 08x17T; EN 1.4510 (Europe); DIN X3CrTi17 (Germany). This steel grade is corrosion resistant in most oxidizing environments (fresh water and boiling acids). Balanced chemical composition provides resistance to intergranular corrosion and high corrosion resistance.

AISI 439% composition

Relevance

The presence in the alloy of aluminum with titanium in combination with low carbon content, gives AISI 439 steel high plastic and strength properties (which are comparable to those of nickel containing AISI 304), higher structural stability when welding or heating. It also combines good plastic deformability (use in stamping processes, hole punching , etc.) with high strength properties. AISI 439 steel is recommended as a substitute for 12X18H9T and 12X18H10T. Stabilized structure of titanium and the low carbon content provides its excellent weldability, the lack of tendency of welded joints to intergranular corrosion (sharp carbide formation begins to occur only at t ° over 1000 ° C.) Corrosion resistance of steel in most environments can be compared with the resistance of austenitic steels AISI 304, 12X18H10T. This steel is resistant to corrosion in water and air, as well as in solutions of most alkalis and many organic acids, in organic compounds containing carbon (including those of animal and plant origin), in a solution of nitric acid.

Another advantage is that, in comparison with austenitic grades containing nickel, this steel is insensitive to intergranular corrosion cracking in the temperature range of 500-800°C and is much less sensitive under load to chloride cracking. Under load, resistance to chloride cracking is ~ 350 MPa, while that of 08Cr18Ni10Ti (and other nickel austenitic steels) is less than 150 MPa.

Comparative characteristics

Ferritic stainless steels are resistant to sulfur containing media compared to nickel containing austenitic steels and are therefore suitable for use in oil, gas and petroleum products and hydrocarbon transfer systems in refineries and gas processing plants. AISI 439 has proven to be an excellent material that is resistant to the gases created in fuel combustion processes. AISI 439 is used in the manufacture of pipes and casings for recirculation, neutralization, exhaust and flue gas recovery systems. Complex high temperature catalytic oxidation-reduction reactions and aggressive gas environments predetermine the use of corrosion resistant economically alloyed steel AISI 439 in production of exhaust systems, furnace and other related equipment (chimneys, exhaust ducts etc .). Such media typically contain products of incomplete combustion (hydrocarbons, carbon monoxide, nitrogen oxides, 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 thermal conductivity than austenitic steels containing nickel, this makes chromium tubular products advantageous in heat exchange applications such as cooling towers. The low coefficient of thermal expansion provides the most reliable fitting and the most rapid heat transfer in food tank cooling systems (water, glycol, and other media cooled systems). Chromium steel piping and weldments change dimensions much less with temperature fluctuations, providing a reduction in fatigue failure stresses with temperature fluctuations, preventing possible leaks from the various hydraulic connections.

Fields of application

AISI 439 can be applied in the production of technological equipment that is used in various stages of food production (hygienic treatment, washing raw materials, equipment and products, separating and sorting products, grinding, mixing, packing and packaging, heat treatment, transportation, etc.). Based on extensive reference books, ferritic steels such as AISI 439 can be used in the manufacture of apparatus and machine parts for the wine industry. Steels of this type are approved for use in direct contact with wine, must, cognac alcohol and waste products. These steels (08Cr17T) are approved for use in dairy and meat industry equipment at temperatures of 30-140°C. All steels of this series (400) including AISI 439 can be used not only as a substitute for the nickel containing grades, but far superior to them in some properties, and be indispensable for food processing equipment. AISI 439 meets all sanitary and epidemiological state norms and rules and is very perspective in application in production of equipment for food industry: meat industry, fat and oil industry, bakery, alcoholic beverage, alcoholic beverage industry, confectionary industry, alcoholic beverage production and others. The high corrosion resistance of this steel is due to the minimum percentage of carbon and high chromium content.

Brand AISI 439 is widely used in industries such as:

-automotive construction;

-Production of kitchen utensils, serving tools, tables, sinks, parts of washing machines, drains, trays and drums for dishwashers, etc..;

-equipment for heat exchangers;

-production of interior and exterior fittings;

-architecture and design;

-civil engineering;

-food industry.

The use of economically alloyed nickel-free stainless steels (i.e. 430 analogues) in processing and food industries is regulated by standards and other regulatory documents.

Tensile strength at high temperatures:

Steel properties at high temperatures

AISI 439 does not harden by heat treatment and exhibits good scale resistance, maintaining useful mechanical properties at high temperatures. This steel is touted as being heat resistant but the actual operating temperature will vary according to environmental conditions.

Welding

This steel exhibits excellent weldability by all known welding methods, provided that passivation, etching/cleaning measures are taken after welding and they do not lose their corrosion properties in the weld joints. For optimum use of inert gas arc welding, it is necessary to keep the energy input to the weld to a minimum. Welding "from above" (i.e., if the surface to be welded is below the welding tool) is recommended. An austenitic wire Sv-07Cr25Ni13, 309L, Sv-08Cr25Ni13BTu can be used as filler material. Electrodes or filler wire of chromium ferritic steel AISI 439 can also be used. To ensure adequate corrosion resistance, it is necessary to remove scale and discolouration by pickling or machining with stainless steel brushes and passivate with a cold solution (10-20%) of nitric acid. Then you need a thorough rinse in cold water and dry.

Buy, bargain price

The company "Auremo" supplies a wide range of products from steel AISI 439. The popularity of this type of products is due to the high quality, great variety and real value. Any product manufactured by us passes strict control over the whole process chain, which provides absolute guarantee of high quality of our metal products. Modern technological capabilities at any stage of production ensure the possibility of individual orders in the absence of the required product in the basic version. Auremo is ready to manufacture high quality steel products according to individual orders.