Characteristics

Grade 03Х21Н21М4ГБ belongs to complex alloyed austenitic steels. It is produced according to the following GOSTs: 5632−72, 7350−77, 25 054−81 as well as TU: 14−1-1190−75, 14−1-2134−77, 14−3-751−78, 14−3-696−78, 14−3-694−78, 14−1-3262−81, 14−1- 4319−87. Such steel is used in the manufacture of welded chemical equipment for the production of phosphoric acid, vinyl acetate, acetyl cellulose, sulphite cellulose, complex mineral fertilizers, as well as in other aggressive environments.

Percent composition

Mechanical properties at t=20 °C

Mechanical properties at 20°C

Note: Maximum and minimum values are given in parentheses.

Mechanical properties at low as well as elevated tº (bars, longitudinal specimens, water hardening process at 1080 °C)

Mechanical properties depending on the degree of cold plastic deformation (longitudinal samples, quenching process in water at 1080 °C)

Physical properties of the alloy

Alloy density 8.0 ^g/cm3; thermal conductivity 17.2 W/(m — K); magnetic permeability 1.252 (μTl — m)/A. modulus of elasticity ^{=18−10−4 N/mm2}; at 300 °C modulus of elasticity drops to 15.9 — ^{10−4 N/mm2};

Temperature coefficient of linear expansion α

Corrosion resistance

This steel is resistant to intergranular corrosion after provoking tempering (700 ° C for an hour). The tests are carried out according to the method, GOST 6032−89. Steel in the quenched state, as well as its welds are resistant to general corrosion, as well as to pitting and intergranular corrosion. In the production of extractive phosphoric acid: in pulp (32% P2O5, 2% F, 2% S03, phosphogypsum) up to 85 °C and in evaporated acid (54% P2O5, 0.5% F) up to 110 °C there is no intercrystalline corrosion. The corrosion rate of this steel does not exceed 0.1 mm/year in the environment of 10−20% H2SO4: up to 80 °C; 10% H2SO4 with an admixture of 7−9% SO2 up to 30 °C; in 96% acetic acid at 120 °C. Corrosion rate in borate pulp containing up to 0.6% H2SO4; 6.03% B2O3 and 5.08% MgO at 90 °C does not exceed 0.001 mm/year. Such steel is used to manufacture turbine type mixers (4.5 m high, Ø 0.3 m, 700 rpm) for mixing slurries containing 32% P2O5, 1.8% F (as H2SiF6, 2.5% S04 (as H2SO4) and phosphogypsum at 70 °C; pulp lines (28−36% P2O5, 1.6−1.85% F; 1.6−3% SO2 at t=70−88 °C), separators, extractors (up to 5.5 m high and Ø up to 8 m) for production of wet-process phosphoric acid (with addition of fluoride ions).

Process parameters

Quenching takes place in water at 1060−1120°C; the same heat treatment is used for hot and cold work hardening. For hot deformation: forging and rolling require t ° 1200−850 ° C, for stamping — 1100−900 ° C. Steel is also well deformed in the cold state, and is also satisfactorily machined by cutting. When bending sheet steel (5 mm thick) in hot and cold condition, the minimum bending radii should be twice the thickness of the sheet.

Welding

This steel is welded by automatic; manual electric arc and argon arc welding. Sheet thicknesses up to 10 mm are satisfactorily welded by all types of manual electric arc welding. The argon arc method is recommended for sheets thinner than 6 mm and for welding root seams thicker than 10 mm. Large parts can be satisfactorily welded by 2 types of manual arc welding at a reduced content of niobium in the metal of the root pass of the weld. To prevent hot cracks in welded joints thicker than 10 mm, the root seams should be welded back-to-back using niobium-free welding materials. The combined method (argon arc welding and welding with piece electrodes) is used for sheet thicknesses over 12 mm. Last, the welds that face the corrosive environment are welded with OZL-17U electrodes.

Electrodes OZL-17U, OZL-26A, ANV-17 with a wire Св-01Х19Н18Г10АМ4 are suitable for manual welding of steel sheet up to 10 mm and for filling of a gap when steel thickness exceeds 10 mm. Coated niobium-free electrodes: OZL-26A on 03X21N21M4 wire (ZI-87) and OZL-17U on Sv-03X23N28MZDZT wire are better when welding root passes of steel with a thickness of 10 mm. And EA-395/9 electrodes are recommended when welding this steel with 08X18H10T, 10X17H13M2T, 10X17H13MZT, 20K and StZ steels.

When manual argon-arc welding of steel sheet up to 10 mm with a non-consumable electrode, as well as for filling of a gap in case of steel thickness more than 10 mm wire Sv-03H23N28MZDZT or 02X21N21M4GB (ZI69) is recommended. When welding root passes of this steel with thickness more than 10 mm, it is recommended to use 03Х21Н21М4 (ЗИ87) wire; when welding automatically — Св-01Х19Н18Г10АМ4 (ЭП690), as well as flux AN-18. The strength of welds = 90% of the base metal. Welded joints of all types of welding are resistant to general and intergranular corrosion.

Supply

Evek GmbH has a wide range of rolled products of 03Х21Н21М4ГБ brand of any parameters in stock. Technical documentation includes data on chemical composition, limiting percentage of impurities; mechanical properties of products. From us it is possible to buy in bulk any semi-finished products for large-scale productions. We also offer optimum conditions for retail buyers. High level of service and prompt service is the face of our company.

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Evek GmbH has an unlimited range of stainless alloys of the highest quality. We offer special alloys at an optimal price. If you are interested in our offer, please contact your nearest office. Qualified specialists will provide all necessary information regarding products, price range, sales conditions. The cost of goods depends on the parameters of products and additional terms of delivery.