Contribution of soviet metallurgy to creation and serial production of KV heavy tank (1939 – 1941)

The KV heavy tank stays among the legends of the Great Patriotic War and one of the most recognizable combat vehicles of those years. The assessment of the tank, its design features and practice of operation, in scientific, popular science literature, and journalism, is still ambiguous: from praise to denial. Historical memory of this combat vehicle is actively living its life not only on pages of the books, but also in the virtual space, in the branches of thematic Internet forums and computer games. The heavy tank of KV series was developed and put into service at the very end of 1939. A new grade of 42S armor steel was created especially for it, which was distinguished by a relatively low content of alloying elements and high adaptability for mass production. The authors seriously studied the stages of armor production and the difficulties in its creation. They show the enormous contribution of metallurgists to the creation of a combat vehicle. As a result of engineering research and the decisive contribution of metallurgy, a formidable machine was obtained, possessing thick armor (75 mm) and quite powerful armament (76.2 mm cannon). At the same time, the tank had a whole range of disadvantages that reduce the effectiveness of its combat use. The general lack of development of the design and archaic technological solutions created serious problems both in the production and in the subsequent operation of this tank. History and tradition of searching the tank allows taking a fresh look at the long glorious traditions of the national engineering school in the field of metallurgy, and its decisive contribution to the Victory in the Great Patriotic War.

A computational investigation on the influence of the l/d ratio and strain rate on the deformation behavior of rolled and homogeneous armor steel in the split Hopkinson pressure bar test process

The present investigation deals with the finite-element analysis of the high strain rate deformation behavior of the quenched and tempered armor-grade rolled and homogeneous armor steel. The rolled and homogeneous armor steel is extensively used in civil and military structures such as battle tanks, armament combat vehicles, combat helicopter, etc. The dynamic deformation behavior of rolled and homogeneous armor steel, that is, resistance against ballistic circumstances relates to its mechanical behavior under high strain rate conditions. In the present research work, a finite-element analysis investigation (using Abaqus finite-element analysis code) has been carried out to evaluate the influence of specimen l/d ratios and high loading strain rates on the deformation behavior and stress–strain responses of the rolled and homogeneous armor steel. Further, an attempt has also been made to check the high strain rate and specimen l/d ratio influence on the strain amplitudes of incident, reflected, and transmitted pulses. The numerical investigation has been carried out with the rolled and homogeneous armor steel specimen with l/d ratios of 1, 0.8, and 0.6. In addition, three high impact strain rates of 2130, 2907, and 3105 s−1 are considered to evaluate the stress–strain responses. The results revealed that the l/d ratio and strain rate have a significant influence on the specimen stress–strain response and the strain amplitudes of incident, reflected, and transmitted pulses. The peak stress value is increased with the increase in the l/d ratio and strain rate. The developed finite-element analysis model has predicted the stress–strain responses with <3% percentage error. The obtained finite-element analysis results have been validated with the experimental investigation with an l/d ratio of 0.6 and a strain rate of 3105 s−1 for rolled and homogeneous armor steel.

Effect of Heat Input on the Ballistic Performance of Armor Steel Weldments

The purpose of this study is to examine the projectile penetration resistance of the base metal and heat-affected zones of armor steel weldments. To ensure the proper quality of armor steel welded joints and associated ballistic protection, it is important to find the optimum heat input for armor steel welding. A total of two armor steel weldments made at heat inputs of 1.29 kJ/mm and 1.55 kJ/mm were tested for ballistic protection performance. The GMAW welding carried out employing a robot-controlled process. Owing to a higher ballistic limit, the heat-affected zone (HAZ) of the 1.29 kJ/mm weldment was found to be more resistant to projectile penetration than that of the 1.55 kJ/mm weldment. The ballistic performance of the weldments was determined by analyzing the microstructure of weldment heat-affected zones, the hardness gradients across the weldments and the thermal history of the welding heat inputs considered. The result showed that the ballistic resistance of heat affected zone exist as the heat input was decreased on 1.29 kJ/mm. It was found that 1.55 kJ/mm does not have ballistic resistance.

Experimental and numerical investigation of Armox 500T armor steel perforation process

This paper presents the results of an experimental and numerical study of the perforation of Armox 500T armoured steel. The plate perforation was performed with a pneumatic gun using three types of penetrators. Sharp, spherical and blunt penetrators were used. The use of different geometries of penetrators causes the process of perforation and destruction of plates in a different state of stress and strain, which leads to the appearance of three basic modes of failure. Numerical analyses of the perforation process have been carried out using the Ls-Dyna computational code with an advanced constitutive model of the material and the integrated failure model. The obtained experimental and numerical results were analysed and compared. The failure shape, the level of plastic deformation and the parameters of stress and strain state were analysed.