Steel AISI 439
Stainless stabilized titanium nickel-free ferritic grade AISI 439 — is the improved analogue of steel 08H17T. According to GOST 5632−72 AISI 439 possesses corrosion resistance in oxidizing environments majority (from fresh water to boiling acids), balanced chemical composition, which provides resistance to intergranular corrosion and high corrosion resistance. Analogues: AISI 439 / 430Ti (USA), GOST 08×17t; EN 1.4510 (Europe); DIN X3CrTi17 (Germany).
|for ASTM A240||0.04 max||1.0 max||0.07 max||0.03 max||0.5 max||17.0−19.0||1.0 max||0.04 max||0.15 max||1.10 max|
The presence in the additive steel AISI 439 Ti and Al plus low carbon content gives it high strength and plastic properties similar to stamp nickel steel AISI 304. AISI 439 has high structural stability during welding and strong heating. It also combines good ductility (required when punching, punching holes) and high strength. This grade, in accordance with GOST 5632−72 is recommended as a substitute for steel 12X18H9T… or 10T. Stabilization of the titanium structure and the minimum percentage of carbon provides excellent weldability, the lack of propensity to intergranular corrosion. Active formation of carbide begins to occur only at temperatures over 1000 ° C.
The corrosion resistance in most environments can be compared with the resistance of steels such as AISI 304 austenitic, 12X18H10T. Brand AISI 439 is stable in water, in the air against corrosion (including oxidation at high temperatures), as well as in most solutions of alkalis and many organic acids, a carbon-containing organic compounds (including animal and vegetable origin) in a solution of nitric acid.
Steel complementary advantages is the fact that in comparison with the austenitic nickel stamps, this steel is not sensitive to intergranular corrosion of the temperature range 500−800 ° C, and much less sensitive to the chloride load cracking. When the load resistance to chloride stress cracking of ~ 350 MPa, while 08X18H10T steels (and other nickel austenitic steels), this value does not exceed 150 MPa.
The table shows the comparative characteristics of steel grades AISI 439 and 12X18H10T.
|mark||The average thermal expansion coefficient (106 ° C-1).||Thermal conductivity at 20 ° C, (W / m • K)||The specific heat capacity at 20 ° C, (J / g • K)||Magnetic quality||Resistance to chloride stress corrosion cracking, MPa|
|AISI 439||10||25||0.44||Yes (ferromagnetic)||350|
Unlike austenitic nickel-containing ferritic stainless steel alloy resistant to sulfur-containing environments, thereby, the steel pipe can be used in systems for pumping the oil, gas and petroleum derivatives in the process plant or refinery gas.
Steel AISI 439 is resistant to the gas environments formed during the combustion of fuel. Such media contain products of incomplete combustion (CO, NO, H 2 S, SO) and the complete combustion (steam, CO 2, NO 2, N 2, SO 2 and so on. D.). AISI 439 is used for recirculation systems, capture and neutralization of waste gases. Resistance to aggressive gas environments cause the use of steel AISI 439 in the manufacture of exhaust systems, heating equipment — exhaust systems, chimneys. Chromium steel having a minimum thermal expansion coefficient and enhanced thermal conductivity compared to austenitic nickel stamps. This predetermines their use in heat exchange systems such as cooling gradilni. Low thermal expansion coefficient of the Fitting fixation ensures reliable and rapid heat transfer during the cooling of food tanks (water, glycol, or similar fluids). Piping and welding pieces of chromium steels have minimal dimensional changes with temperature variation that reduces destructive fatigue loads at temperature drop preventing unintended leakage of the hydraulic connections.
Use in food industry
Ferritic steel similar to AISI 439 popular in the wine industry. They are approved for use in contact with the wine, wort, cognac alcohol, as well as others. Winemaking products. Allowed the use of such steels (08H17T) for the production of equipment used in the meat-packing industry at temperatures up to 140 ° C.
AISI 439 steel demand in the manufacture of food processing equipment manufacturing (hygienic processing of raw materials, equipment and products, separation, mixing, sorting, grinding, packaging, heat treatment, transportation). All this became the 400 series, in t. Ch. AISI 439 can not only replace the nickel grade, but significantly exceed them in a number of properties, particularly for the food industry.
AISI 439 fully meet the state standards and SNIP is very promising in the production of equipment for processing and food industry: meat, fat, baking, alcohol, beer and soft drinks, confectionery, alcoholic beverage, and others.
— Transport machinery;
— Civil engineering and design;
— Manufacture of kitchen appliances, tableware;
— Manufacture of sinks, parts washing machines, sinks, trays and reels for dishwashers
— Production of internal and external accessories.
The use of nickel-free economically-alloyed stainless steels (430 analogs) in the processing and food industries regulated by the relevant regulations.
Ultimate strength at high temperatures:
|Temperature, ° C||Tensile strength, MPa|
Effect of high temperature
AISI 439 is not hardened by heat treatment, has good resistance to the formation of scale, maintaining performance properties useful to a temperature of 850 ° C. It is positioned as a heat-resistant, however, the actual operating temperature depends on the aggressiveness of the conditions of the environment.
Welded by any methods without losing corrosion resistance welding in places subject to a post-weld treatment: a passivation etching / cleaning. Arc welding in an inert gas atmosphere requires minimal power consumption. Welded surface located below the welding tool. The wire-Savanoriu Str 07Kh25N13, 309L, St-08H25N13BTYU used as filler material. You can use electrodes or wire to the base of the brand AISI 439. To ensure corrosion resistance, remove scale, process annealing color space etching or brushes made of stainless steel and cold propassivirovat 10−20% HNO3 solution. Next, you need a thorough washing and drying.
All products are certified grade AISI 439… The technical documentation includes data on the chemical composition, limiting the percentage of impurities; mechanical properties of products. We can buy in bulk, any semi-finished products for large-scale productions. We also offer optimal conditions for retail customers. High level of service and efficiency of service are the face of our company.
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In stock company «Electrovek-steel» is represented by a diverse range of stainless steel alloys. We supply certified products of domestic and foreign manufacturers. Our staff members are always happy to provide expert assistance in the selection of metal-roll. We employ some of the most experienced management consultants. Strict compliance with the rules of production, excellent product quality and minimal lead times are the face of our company. For regular customers introduced discount prices.