Development of technology for the production of a lightweight observation and protective container (LOOK) made of nanostructured ultra-strength steels

The article contains results of research and analyses concerning application of nanostructured bainitic steel in the form of plates for manufacturing of armour components. The presented results of examination of microstructure and properties include a wide range of laboratory experiments and industrial tests, which resulted in the achievement of the assumed functional properties. In the period of 2017-2021, a scientific and industrial consortium consisting of Łukasiewicz – Institute of Ferrous Metallurgy (leader); WITPiS, Tarnów Mechanical Works, Alchemia and Heatmasters Poland carried out a project funded by the POIR 04.01.04 programme aimed to develop the design and to manufacture an observation and protective container with a specified resistance to penetration by armour-piercing projectiles and with a lower mass of steel armouring in relation to that currently produced. The aim of the project was achieved by using armour plates made of nanostructured bainitic steel (nanobainitic), which are characterised by high resistance to high-energy impact concentrated in a small area. The technological tests carried out in the project mainly concerned the development of a new container and industrial technology of armour plates production and their application in the armour of this container. Based on the results of investigation of the semi-industrial scale material, the optimum chemical composition for industrial scale melting and casting was determined. An industrial technology for the production of plates of nano-structured bainitic steel was developed, which includes the following processes: smelting and casting, preliminary heat treatment and ingot hot processing, as well as hot rolling, final heat treatment, and surface treatment. A test batch of the material in the form of 1500×2470 mm armoured plates was fabricated under industrial conditions. The final result of the project is a container armoured with bainitic nanostructured steel plates with implementation documentation and a technology for producing armoured plates from this steel under the technical and technological conditions of domestic steel manufacturers.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF STEELS FOR SHAPED CHARGE LINERS AND PRELIMINARY ASSESSMENT OF THE EFFECTIVENESS OF EXPERIMENTAL SHAPED CHARGES INTENDED FOR USE IN THE MINING INDUSTRY

The paper presents the results of investigation of the microstructure and mechanical properties of Fe-based materials designed for the manufacture of semi-spherical liners for experimental shaped charges. The tests were carried out on material samples taken from two semi-finished products, i.e. a rod for the manufacture of charge liners with a diameter of 50 mm using machining, and sheets for the manufacture of liners with a diameter of 100 mm using cold drawing. Microstructure examination was also carried out on a test specimen obtained using the additive method (3D-WAAM), made of low-carbon unalloyed steel wire. Firing tests on concrete blocks were carried out in order to quantify the effects of drilling at the Experimental Mine Barbara. The scope of the tests consisted of firing at cylindrical concrete blocks using projectiles containing 50 mm diameter liners made of Fe-based alloys. Based on the results of the laboratory material, two experimental steel grades were selected for further testing. Plates made of the selected steels will be used to manufacture charge liners with a diameter of 100 mm.

STRUCTURE AND MECHANICAL PROPERTIES OF 21HMF STEEL STEAM TURBINE ROTOR MATERIALS AFTER LONG-TERM OPERATION FOR A TIME SIGNIFICANTLY EXCEEDING THE DESIGN TIME

The article presents the results of tests of materials for steam turbine rotors with various degrees of depletion in order to determine the suitability of these components for further operation after significantly exceeding the design working time on the basis of the assessment of the microstructure condition and a set of functional properties.

STUDY ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF 42CrMo4/NANOS-BA® HIGH-STRENGTH CLAD PLATES AFTER THE PROCESS OF HOT ROLLING AND TWO-STAGE HEAT TREATMENT WITH ISOTHERMAL TRANSFORMATION

The aim of the study was to develop a technology for welding non-weldable 42CrMo4 and NANOS-BA® steel grades in the process of hot rolling and two-stage heat treatment. As a result of physical experiments carried out in a line for semi-industrial simulation of the production of metals and their alloys (LPS) and additional heat treatment, a durable combination of 42CrMo4 and NANOS-BA® steels with high mechanical properties was obtained, including: Rp0.2 = 1036 MPa, Rm = 1504 MPa and A = 10.9%, without microscopically visible cracks and other discontinuities in the joined surface. The quality of the 42CrMo4/NANOS-BA® clad plates produced in this way was assessed on the basis of microstructure examination as well as bending, shear and tensile strength tests.

THE ROLE OF INSTITUTE OF FERROUS METALLURGY IN THE DEVELOPMENT OF MATERIALS FOR THE POWER INDUSTRY

The article presents an outline of the development of the domestic energy sector from the very beginning of its operation. It discusses the impact of the research conducted at the Stanisław Staszic Institute of Ferrous Metallurgy in Gliwice on the selection of steel grades for operation at elevated and high temperatures for applications in the Polish power industry. The article presents the research and implementation achievements of the research workers of the Institute with the discussion and the purpose of their creation. The article presents the area of joint scientific and research achievements of the Institute of Ferrous Metallurgy with affiliated domestic and foreign research centres, documented by numerous research projects and publications in renowned scientific journals.

METHOD FOR HEAT TREATMENT OF THE RUNNING SURFACE OF THE HEAD OF THE PEARLITIC STEEL RAILS

The paper deals with the new approach to the optimization of the pearlitic rail’s head hardening process aimed at balancing the relation between strength and ductility of the head running surface. In the industrial process, efforts have been undertaken so far to maximize the hardness of the rail’s head while maintaining its pearlite structure, resulting in obtaining enhanced wear resistance and resistance to the contact fatigue defects initiation. The new approach, described in this paper, aims at designing the head hardening process enabling achievement of the high hardness of the running surface combined with high ductility expressed in terms of the total elongation. To achieve this aim of the investigation, a computer program was developed capable of predicting the occurrence of the phase transformations during rail head cooling and microstructure features after cooling. The program was linked with dedicated inverse module enabling the adjustment of the cooling conditions to achieve the required state of the pearlitic structure.

STUDY ON REMOVAL OF COPPER, TIN AND ARSENIC FROM IRON ORE, SCRAP AND STEEL IN THE LIGHT OF THE LATEST STATE OF METALLURGICAL TECHNOLOGY

The study investigates the ability to remove copper, tin and arsenic from iron ore, scrap and liquid steel based on the literature and thermodynamic calculations using the FactSage 7.2 software. Methods of removing Cu, Sn and As from iron-bearing materials, feasible in industrial conditions in the near term, were selected. Simulation tests with the use of the FactSage 7.2 software showed that under reduced pressure conditions Cu and Sn can be removed from the steel bath, while As evaporation is not possible. Laboratory tests were carried out, including the removal of Sn and Cu in the process of degassing of liquid steel in a deep vacuum in a vacuum induction furnace and the removal of Sn from iron ore in the sintering process. Under conditions of deep vacuum (below 40 Pa), high temperature (1670°C) and a correspondingly long vacuum treatment time (over 30 minutes), the efficiency of removing the copper and tin contents from the liquid steel of approximately 14 and 17% respectively was obtained. The iron ore sintering test with a high Sn content showed the effectiveness of reducing the Sn content during this process, amounting to approx. 30%.

PRODUCTION TECHNOLOGY AND MECHANICAL PROPERTIES OF A NEW GRADE OF STEEL FOR FORGINGS WITH INCREASED STRENGTH AND IMPACT STRENGTH

The study involved the development of the basics of production technology and the testing of the mechanical properties of a new grade of steel for forgings with increased strength and impact strength, intended for special products. The scope of the tests includ-ed a proposal for a new steel composition along with the production of ingots and its further processing into forgings in industrial con-ditions, using an input with various dimensions of the cross-section, proposed as a result of numerical calculations, including the performance of heat treatment in two variants. As a result of tests and analyses, it was found that the proposed technology enables the production of semi-finished products with the assumed level of strength and impact strength.

USE OF CONIFEROUS WOOD BIOCHAR AS A SUBSTITUTE FUEL IN AN IRON ORE SINTERING PROCESS

The article presents the results of tests carried out at Łukasiewicz – IMŻ, in cooperation with the Institute for Chemical Processing of Coal, on the use of biochar from coniferous wood as a substitute fuel in the iron ore sintering process. It was found that, considering productivity, fuel consumption and properties of the obtained sinter, the content of the tested biochar should not exceed 10 wt% in total fuel. When using the tested biochar, the content of FeO in the sinter decreased. The sinter was characterised by better ISO T strength than when using only coke breeze. At the same time, the grindability of the ISO A sinter decreased with the increase in the content of the biochar in the total fuel. The use of the tested biochar can have a very positive effect on both the sinter strength and its reducing properties.

INFLUENCE OF ALLOYING ELEMENTS ON THE MICROSTRUCTURE OF NEW COBALT MATRIX SUPERALLOYS REINFORCED WITH PHASE – L12

The article presents selected results of research on the primary structure of a new generation of cobalt-based Co-20Ni-10Al-5Mo-2Nb superalloys. Research on this group of materials was started in 2006 by J. Sato. These materials are anticipated to be able to replace nickel-based superalloys in the future due to their superior elevated temperature properties compared to the nickel-based superalloys. Today, γ’ nickel-based superalloys are still unrivalled in aerospace applications, however, cobalt-based superalloys are a response to their existing limitations, which do not allow the current pace of aircraft engine development to be maintained.