Characteristics

Alloy grade Н70МФВ-VI on nickel base is melted in the vacuum induction furnaces. It is used in the manufacture of welded chemical equipment (heat exchangers, tanks, reactors) operated at elevated temperatures in hydrochloric acid environments, concentrated solutions of phosphoric, acetic andsulfuric acids, in the production of hydrogen halocarbons, acetic acid, polypropylene, ion exchange resins, in organic synthesis processes and in the production of chemical and pharmaceutical preparations. It withstands media pressure up to 5 N/mm² and tº from -70 to 500 °C. The following specifications are provided for H70MFV-VI alloy: 14-1-2230-77; 14-3-1-1227-83; 14-1-2260-77; 14-1-4684-89; GOST 5632-72.

Chemical composition:

Mechanical properties at 20 °С

Mechanical properties of 10 mm thick plate, quenched at 1070 °C in water

Mechanical properties of 10 mm thick sheet, quenched at 1070 °C in water

Mechanical properties depend on the degree of cold deformation (sheet thickness 2 mm, quenching process in water before cold deformation at t ° 1070 ° C)

Physical properties

The density of 9.2 g/cm3, the shear modulus at temperature of 20-100 ° C is 23 - 10-4, N / mm2; at temperature of 20-400 ° C - 22 - 10-4, N / mm2; at t ° 500-700 ° C - 20 - 10 - 10-4, N / mm2; at t ° 500-700 ° C.4, N/mm2; thermal conductivity at t° 20 ° C is 0.113 - 10² W/(m - K); specific heat capacity at 20 ° C = 378 J/(kg - K); and the alloy's specific electrical resistance is 1.55 Ohm-mm2/m

The values of the temperature coefficient of linear expansion α

Corrosion resistance

According to the following specifications: 14-1-2260-77, 14-1-2230-77. 14-3-1-1227-83, 14-1-4684-89 this alloy must have resistance to intergranular corrosion after provoking tempering at t ° 800 ° C (30 min), as well as testing in boiling control 21% hydrochloric acid solution (200 hours). The alloy is characterized by high corrosion resistance to the following aggressive substances:

• In 10-93% H2SO4 at 95 °C and in boiling solutions of 10-40% H2SO4, the corrosion rate is no greater than 1 mm in10 years; in 1-10% H2SO4 at 70 °C (then the acid has oxidizing properties) the corrosion rate is 2 mm in 10 years;
• In hydrochloric acid at different concentrations and at any tº, including at boiling; in the concentration range of 1-37% HCl at 25-70°C, in boiling hydrochloric acid solutions of up to10% corrosion rate of this alloy, alloyed with 2% Mo, is not more than 2 mm for 10 years; in boiling hydrochloric acid solutions with concentration of 15-21% - not more than 3-4 mm for 10 years;
• in phosphoric acid of any concentration, except 94%, to a temperature of 140°C, the rate of corrosion of steel is less than 0.2 mm for 10 years. In polyphosphoric acids at 100-200°C, the corrosion rate is no more than 4 mm per 10 years; in halogens (iodine, fluorine and bromine), pure orHalogenic acids (iodine, fluorine and bromine) pure or containing acids which are reducing in nature, such as hydrofluoric acid (up to 80% concentration at room temperature, up to 10% at 70°C), iodine hydrogen iodide, hydrogen bromide and chlorosulfonic acid;
• in moist hydrogen chloride;
• in organic acids, including formic acid (at 10-90% HCO2 at boiling, 50-80% HCO2 at 140 °C under pressure) and acetic acid (50-80% CH3OH at boiling, 98% CH3OH at 165 °C under pressure).

Alloy H70MVF-VI also has a 1 point resistance in hydrochloric acid (5-37% concentration to tº boiling), sulfuric acid (up to 50% concentration at tº boiling, up to 55% concentration at 120 °C) and in chlorides. Nickel molybdenum alloys are not resistant in nitric acid, metal chlorides (copper, iron, etc.) and other environments that have oxidizing properties. Even a small amount (10-4%) of oxidants (oxygen, chlorine, trivalent iron ions, copper, etc.) in solutions of sulfuric and hydrochloric acids sharply reduces the corrosion resistance of such alloys.

Process Parameters

This alloy is available to any type of processing: forging, rolling, stamping, pressing, drawing. The hot deformation is carried out in the thermal range of 1220-950°C with a long pre-exposure time at tº heating. The alloy is more prone to burnout than 18-10 type austenitic steels, which is why it requires additional intermediate heating during pressure treatment. After forming, products are necessarily heat-treated at t° 1070+20°C (3-5 min/mm section exposure), as well as cooled under a water shower. Alloy cutting (drilling, turning, milling) is carried out at reduced speeds using hard alloys ВК3, ВК3М, ВК6М, and for drilling - alloys ВК10 ВК10М, ВК15, ВК15М. Alloy is welded by electric arc or manual argon-arc method. In the latter case, the filler material used wire H70M-VI (EP495) according to TU 14-1-673-82) or H65M-VI (EP982), according to TU 14-13 281-81. For electric arc welding OZL-23 electrodes are used. Welding should be carried out with intensive cooling. Welded joints have high mechanical strength (σ0,2 = 350 N/mm2, σ in 720 N/mm2, δ5 = 35%, KCU = 150 J/cm²), resistance to intergranular corrosion, including knife-type.

Delivery

All the presented H70MVF-VI products are certified. The technical documentation includes data on the chemical composition, the limiting percentage of impurities; mechanical properties of the products. From us you can buy in bulk any semi-finished products for large-scale productions. We also offer optimum conditions for retail buyers. The high level of service and responsiveness of service is the face of our company.

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