Steel 45Г17НМФ (MML-3)
Designation
Description
45Г17НМФ steel is used: for the manufacture of castings by sand casting parts, buildings, machinery and equipment of the Navy ships of all classes, types and appointments, as well as ballast, which is required of namagnichennosti μ≤ 1,262·10-6 G/m (1,005 GS/e) group I (ballasts, keys, on-Board mooring fairleads, etc.), group II (mortars, bearing housings of the spindles, the hubs of rudder blades, covers, housings, levers, sprockets windlasses, the plates and drums are the base of the spires, etc.) and group III (propeller shaft brackets, stem, glasses of end and intermediate brackets, post rudder, spinners, anchors, mortars, etc.).
Note
Vysokoorganizovannaja low austenitic steel.
Difficult the production of thin-walled complicated castings because of the tendency of steel to the formation of oxide captivity.
Magnetic permeability μ ≤ 1,005 GS/e and is almost constant in any thermal and thermomechanical processing. The magnetic field of the casting is increased in the presence of penetration and in particular the ferromagnetic oxides.
Do not use steel grades for cast metal parts, running on friction (bushings, worm wheels, gear) or requiring surface hardening by nitriding, as well as parts of valves and similar parts. Unacceptable use of steel for the manufacture of parts without cathodic protection, operating in seawater and other environments that cause intense General corrosion.
Steel has low frictional properties and surface hardening (nitriding and carburizing) is not exposed.
Steel is not prone to intergranular corrosion and acquires a tendency only after a long vacation at a temperature of 650−700° C and this is due to the precipitation of carbides along the grain boundaries of austenite. Steel is prone to General corrosion. Therefore, it is recommended to use protectors in conjunction with paint coatings.