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The review describes methods of stress corrosion cracking (SCС) tests that implement various conditions for samples loading: at a constant static load or deformation, at a constant or increasing load of samples with a previously grown fatigue crack, with a slow strain rate. Such tests shall be carried out to determine the resistance of shipbuilding materials to be used in loaded ship structures in contact with seawater. Brief descriptions of the mechanism of stress corrosion cracking of steels and alloys are given. The necessity to carry out bench tests of steels and their welded joints, as well as models simulating individual units and elements of structures, is indicated. At this stage, conditions are ensured as close to operating conditions as possible due to exposure in various climatic zones of the world’s oceans (variations in temperature, chloride concentration, amount of dissolved oxygen, degree of biofouling, and their simultaneous impact). It is shown that during verification field tests (final stage) new materials promising for operation in marine conditions pass the final evaluation of corrosion resistance in the form of elements of ship structures and systems in the conditions of ship operation.

Shipbuilding steels and alloys may be subjected to various types of corrosion damage when exposed to sea water. For reliable long-term operation of ships and marine structures, despite the use of corrosion protection, materials are chosen that, in addition to the required mechanical properties, have sufficient corrosion resistance to ensure a given service life. Evaluation of corrosion resistance of new materials for use in shipbuilding was made by carrying out mandatory delivery trials using methods that have been repeatedly tested experimentally and whose results have been confirmed in practice. The complex study of corrosion resistance of steels and alloys is based on step-by-step laboratory, bench, and field tests. The review provides a brief description of laboratory corrosion test methods that are part of mandatory delivery trials. Parameters determining the aggressiveness of seawater as a corrosive medium, including salinity, oxygen content are considered. Laboratory test methods include electrochemical studies with determination of potential and rate of corrosion, pitting potential on the basis of polarization curves construction, as well as the generally accepted gravimetric method of corrosion rate determination. Installations for testing in moving (with varying flow rate) seawater are given.

The paper presents the results of a study of the structure and mechanical properties of high-strength austenitic dispersionally hardened Mn–Ni–V–C steel with a yield strength of at least 700 MPa. Its composition and the hardening method were selected so that the steel meets the requirements for high strength and nonmagnetic properties. It is shown that the introduction of 1–2% Cu into Mn–Ni–V–C steel expands the region of existence of the γ-phase in the Fe–Ni–Mn phase diagram, narrows the two-phase γ+α-region and shifts it towards lower Mn contents, increasing stability of austenite to martensitic transformation during cold deformation. A numerical assessment of the influence of alloying austenite-forming elements Ni, Mn, Cu on the critical degree of cold plastic deformation, leading to the formation of deformation martensite in steel, is proposed. The temperature range of the reverse transformation of this martensite into austenite during annealing is established, depending on the nickel content in the steel. For precipitation hardened steel with a composition of 10%Mn; 10%Ni; 2%Cu; 0.3–0.4%C; ~1.4%V the regularities of dissolution upon heating for quenching and precipitation during aging of particles of the strengthening carbide phase VC were studied. It has been shown that the maximum strength is achieved after quenching from 1150°C and aging at 650°C for 15 hours. Taking into account the studies carried out on the stability of austenite, static and cyclic strength and durability, the optimal alloying range of steel with nickel, manganese and copper was substantiated, and the optimal mode of heat treatment was revealed, which provides a combination of high strength with good ductility and toughness of steel.

This work presents tests’ results on the corrosion and erosion resistance of nitrogen-containing steel 04Kh20N6G11M2AFB in comparison with steel 08Kh18N10T, AB2-2 and VT1-0 titanium alloy. It is difficult to determine steel wear resistance against ice with abrasive (20%) due to the rapid melting of ice. It has been shown that the most effective methodology for assessing the corrosion-erosion resistance to simultaneous impact of abrasive and a 3.5% solution of NaCl to the metallic surface consists in the determination of the repassivation rate of the oxide film. It was found that the electrochemical potential of 04Kh20N6G11M2AFB stainless steel recovers 1.5 times faster than that of 08Kh18N10T steel, so it is very promising to use nitrogen-containing steel as a cladding layer of bimetallic alloy for icebreakers belts manufacturing.

The structure of the adhesion zone between the base and cladding layers in new 10KhN3MD + 04Kh20N6G11M2AFB two-layer steel obtained using different techniques, namely, application of deposit welding followed by rolling, pack rolling, and explosive welding, is studied. It is found that, irrespective of the chosen technique of preparation, the strength of adhesion of the layers is at the level of the strength of the steel of the base layer.

Regularities of corrosion damage in the case of pitting and gap corrosion are studied on samples of austenitic stainless steel (AINSI 316L) produced using the powder selective laser-melting (SLM) technique. It is found that the corrosion rate and the appearance of corrosion damage considerably depend on the surface state and heat treatment. Heat treatment (austenitization) results in a decrease in the local corrosion rate by 20–25%, a decrease in the number of pittings, and smoothing of the crevice corrosion profile as compared to the initial SLM state. The opening of the subsurface pores in the course of machining somewhat decreases corrosion resistance. It is shown that the initiation and development of pitting and crevice corrosion are related to the presence of surface and subsurface pores in the SLM material.

The paper presents results of comparative studies of corrosion resistance and corrosion-mechanical strength for low-magnetic shipbuilding steels of alloying systems Mn–C, C–Mn–Ni, Cr–Ni, Cr–Ni–Mo, and Cr–Ni–Mn–N, produced using various hardening mechanisms. It is shown that nitrogen-containing steels developed by CRISM Prometey constitute new constructional material superior in resistance to corrosion cracking in seawater compared with low-magnetic steels used in shipbuilding nowadays.

Austenitic steel Kh20N6G11AM2BF with a nitrogen content of 0.4 wt % exhibits enhanced mechanical properties, high wear, and high resistance to stress-corrosion cracking (SCC) after quenching from rolling heating and after quenching from 1150°C and 15% cold deformation. This shows that it can be used in arctic shipbuilding as a cladding material for hull plates. Strong bonding of Kh20N6G11M2AFB austenitic steel cladding with a nitrogen content of 0.4 wt % with 10N3KhDMBF hull steel is obtained. The shear resistance is registered to be 437–520 MPa. Redistribution of the alloying elements with the formation of a martensitic layer, which is observed at the interface between the cladding layer and the base material, must be taken into account in the final heat treatment considering different processing conditions.

The structural, mechanical, and magnetic properties of metal cut out from the welded joint and from the near-weld zone of the welded joint of high-strength nitrogen-containing 04Kh20N6G11M2AFB austenitic steel have been investigated. The behavior of the magnetic parameters of materials under study subjected to various schemes of loading, such as tension, torsion, internal pressure, and combination of tension and torsion have been investigated. It has been established that the metal of the welded joint and near-weld zone of the welded joint, just as the base metal, has a stable phase composition and magnetic properties under various loading conditions. It has been concluded that 04Kh20N6G11M2AFB steel can be used in the fabrication of welded parts and elements of welded constructions that require low magnetization and high stability of magnetic characteristics under the force action.

The paper depicts long-term research resulting in creation of high-nitrogen austenitic steels for shipbuilding. It shows the influence of the chemical composition and technology on the crystal lattice and steel structure, mechanical and corrosion properties, weldability, and other characteristics. The paper studies the fine structure of nitrogen austenitic steels and shows the important role of nitrogen, which impacts the strength and corrosion resistance more effectively than carbon while maintaining a high level of plastic properties and resistance to cyclic and dynamic loading. Magnetic and vibrodamping characteristics are evaluated. High-strength nitrogen austenitic steel with the yield strength of 650 MPa has been successfully adopted by the domestic industry. Its implementation for heavy duty structures is in the final stage. A prognostic evaluation for further development of nitrogen austenitic steels for various industries is given.

We report on the studied influence of the applied normal and tangential stresses, as well as their combined effect on the structure, phase composition, and magnetic properties of three high-nitrogen steels (HNS). Two of the studied steels in the initial state had an austenitic structure and were diamagnetic. The third steel, according to the data of the X-ray diffraction and metallographic analysis, contained 7% δ-ferrite in its composition, which specifies its ferromagnetic properties. The nitrogen steels studied in this work have demonstrated the stability of the phase composition, as well as of the magnetic properties at various loading conditions, and, thus, can be used in the production of articles and elements of structures that are required to exhibit low magnetization and high stable magnetic characteristics under an applied force. Parameters that can be used as the informative ones when estimating changes that occur upon the production and exploitation of articles and elements made of HNSs with small contents of δ ferrite have been determined.

The structural state and the resistance to stress-corrosion cracking (SCC) at constant loads have been studied using samples with a grown crack by the method of the cantilever bending on quenched austenitic stainless steels of the 20Cr-6Ni-11Mn-2Mo-N-V-Nb (Kh20N6G11M2AFB) type, with different contents of nitrogen (0.17, 0.34, 0.43, and 0.50 wt % N). The tests were conducted in a 3.5% aqueous solution of NaCl (without providing polarization) and in a similar solution under cathodic polarization, which causes the formation of hydrogen. It has been shown that, in a chloride solution without polarization, the steels do not undergo SCC for 2000 h. In the case of significant cathodic polarization via employment of a magnesium protector, there was revealed a brittle character of fracture upon SCC in all steels. It has been shown that steel with a nitrogen content of 0.43 wt % possesses the maximum absolute values of rupture stresses under the conditions of cathodic polarization.

04Kh20G11N6M2AFB steel is subjected to shock tests in the following two states: after high-temperature mechanical treatment (HTMT) and after HTMT followed by quenching. The dynamic yield strength, the spall strength, and the structural transition threshold induced by shock loading are determined. It is shown that these parameters weakly depend on the shock loading rate in the steel after HTMT and increase slightly in the steel quenched from a temperature of 1100°C. In both cases, the mass velocity defect at a compression pulse plateau increases sharply beginning from a certain threshold strain rate, which indicates a high energy absorption ability of the steel.

Structural changes and resistance to the stress-corrosion cracking of the nitrogen-bearing austenitic steels 04Kh20N6G11M2AFB and 09Kh20N6G11M2AFB (with 0.04 and 0.09 wt % C, respectively) after different treatments, including thermomechanical action, quenching from 1200°C, and aging at 700°C for 2 and 10 h, have been studied. It has been shown that aging at 700°C of the air-melted austenitic steel 09Kh20N6G11M2AFB leads to a decrease in the strength of samples with an induced crack upon the cantilever bending in air and in a 3.5% aqueous solution of NaCl as compared to the strength of the steel 04Kh20N6G11M2AFB-EShP with a smaller carbon content after high-temperature mechanical treatment or quenching from 1200°C. The smallest resistance to stress-corrosion cracking is observed in the samples of 09Kh20N6G11M2AFB steel after 10 h of aging, which is accompanied by the most intense acoustic emission and by brittle intergranular fracture. This is explained by the high rate of the anodic dissolution of the metal near chromium-depleted grain boundaries due to the formation of continuous chains of grain-boundary chromium-containing precipitates of carbides and nitrides.

Specimens of a 10N3KhDMBF shipbuilding hull steel were clad by a 04Kh20N6G11M2AFB nitrogen austenitic steel using various treatment conditions, which included hot rolling, austenitic facing, and explosive welding followed by hot rolling and heat treatment. Between the base and cladding materials, an intermediate layer with variable concentrations of chromium, manganese, and nickel was found, in which a martensitic structure was formed. In all the cases, the strength of bonding of the cladding layer to the hull steel (determined in tests for shear to fracture) was fairly high (σsh = 437–520 MPa). The only exception was the specimen produced by unidirectional facing without subsequent hot rolling (σsh = 308 MPa), in which nonfusions between the faced beads of stainless steel were detected.

We report on the study of the structure, mechanical and magnetic properties of metal cut out from different zones of the welded joint of high-nitrogen-containing austenitic steel 04Cr20Ni6Mn11Mo2NVNb. The patterns of change in the magnetic parameters of the investigated materials under various schemes of loading (tension, torsion, tension and torsion combined) are investigated. It is found that the weld material and the heat affected zone (HAZ) material of the welded joint, as well as the base metal, reveal the stability of their phase compositions and magnetic properties under different loading conditions. A conclusion is made about the possibility of using the 04Cr20Ni6Mn11Mo2NVNb steel for the parts and elements of welded structures that require low magnetization and high stability of magnetic characteristics under an applied force.

The paper describes a complex of research on the study of the mechanical properties, fractographic features of the fracture and evolution of the structure of the nitrogen-containing stainless steel 04Kh20N6G11M2AFB (0.47 wt. % N) with an austenitic structure under static tension at temperatures ranging between −70 and +140 °C. A new effect has been revealed, namely, a more intensive growth of the strength characteristics with a simultaneous increase in the plasticity characteristics of the 04Kh20N6G11M2AFB steel under static tension at temperature decreasing in the range between +50 and −70 °C as compared with strengthening rate and plasticity characteristics at temperature decreasing in the range between +140 and +50 °C. It has been found that the ductile nature of fracture still prevails for the steel 04Kh20N6G11M2AFB at tensile testing temperatures decreasing to −70 °C, and this corresponds to the lower boundary of the range of negative climatic temperatures.

The effect of water quenching from rolling heating at 1100°C on the structure, the mechanical properties, and the static fracture toughness of corrosion-resistant austenitic high-nitrogen 0.4Cr20Ni6Mn11Mo2N0.5 steel shot-rolled at 1100–900°C is studied. It is found that, after quenching, the initially hot-deformed steel possesses a quite high fracture toughness, although quenching from 1100°C decreases its fracture toughness by 11.4%. An analysis of fracture surfaces indicates a ductile character of failed quenched steel specimens. The specimens have fracture regions close to a quasi-cleavage at the stage of stable crack growth.

The effect of the thermomechanical treatment parameters on the structure and properties of a high-strength nitrogen-bearing austenitic Cr-Ni-Mn steel is studied using a Gleeble 3800 plastometer. An increase in the interdeformation pause time during multipass deformation of the steel is shown to decrease the temperature of formation of carbonitride hardening phases in its structure. A shift in the temperature range of deformation toward low temperatures is found to increase the strength properties of the steel, and its plasticity decreases.

The effect of alloying elements, such as chromium and nitrogen (at their overequilibrium contents), and heat-treatment conditions (quenching from 1200°C, tempering at 400 and 600°C for 2 h) on the pitting corrosion resistance of chromium-nitrogen steels containing 15–21% Cr and 0.4–1.22% N in chloride solutions is studied. A relation is established between the structural and phase states of the chromium-nitrogen steels and the character of anode polarization curves and the potentials of pitting formation and repassivation. It is found that the pitting corrosion resistance of the chromium-nitrogen steels tempered at a temperature of 600°C decreases significantly because of the formation of chromium nitrides.

The structure and mechanical properties of nitrogen-bearing (up to 0.45% N) austenitic steel of type 04Kh20N6G11AM2BF are studied after hot rolling, hardening from different temperatures, and cold deformation.

Two kinds of steel—30CrNi4Mo armor steel and austenitic 04Cr20Ni6Mn11Mo2NVNb (nitrogen) steel—have been taken for comparative experimental studying a shock-wave behavior under uniaxial strain conditions. For the first kind of steel, transferring energy from load to deformed body is found to be realized through intermediate structural scale (mesoscale), whereas for the second kind—directly, i.e. with-out intermediate scale level.