The paper is devoted to comparison of electroslag remelting (ESR) with consumable electrode and electroslag refining with liquid metal (ESR LM) processes. The possibility of rearrangement of the heat contributions coming from the consumable electrode and current supplying mould (nonconsumable electrode, CSM) makes the core of the ESR process organisation in the CSM. The usage of liquid metal instead of consumable electrodes allows to reduce liquid bath temperature and volume in order to provide low segregation ingot. The formal assessment of physico-chemical conditions and experimental measurements of desulphurisation have shown the same level of refining ability of both processes. Replacing the classic ESR by the ESR LM is a prospective way to produce high-quality ingots from sophisticated and hard-to-deform materials, whereas manufacturing of the consumable electrodes is technically problematic and costly.

Purpose: To develop novel ESR based process for composite ingot with shallow transition zone between layers in order to produce efficient heavy-weight rotors for steam turbines. Design/methodology/approach: The nowadays heavy-weight rotors for steam turbines for power plants are monoblock or two or more layer in length composite part facilitating operation in different zones withstanding various loads and working medium. However, the joining of various steel in composite rotors by welding has low productivity. The ESR now is recognised as the best available technology for the big-diameter and mass forgings for power generating machines, including rotor ones. The ESR affords the most favourable conditions of solidification resulting in homogenous low-segregation ingot with smooth surface and high-quality structure. The step ahead is the ESR for composite. Findings: The two-layer model ingot had produced from steel grades 12Cr13 and 35NiCrMoV12-5 were manufactured using the electroslag process with the liquid metal (ESR LM) in the CSM of 180 mm in diameter with ingot withdrawing. The transition zone in two-layer ingot had have the shallow shape and low depth with the even macrostructure without defects of the same type as both joined steels. The metal of the transition zone fully satisfies standard requirements for properties of both steel grades in the heat treated and as-cast conditions. Research limitations/implications: The ESR LM can provide both the monobloc heavy ingots with uniform structure and composites with low-stress connection between metal layers for heavyweight rotors and other critical products manufacturing.

A new slag susceptible to self-disintegration in the solid state due to formation of dicalcium silicate (2CaOSiO 2 ) was developed. This compound reduces the thermodynamic activity of silica in a slag and, consequently, decreases silicon reduction and its transition to metal in the electroslag remelting process.

Зроблено огляд тенденцій розвитку залізничного транспорту і пов'язаних з ними змін умов експлуатації та виникнення дефектів, що скорочують строк служби рейок. Зростання швидкості руху пасажирських потягів і збільшення навантаження на вісь при перевезенні вантажу вимагає покращення якості рейок і властивостей сталей, з яких їх виробляють. Збільшення інтенсивності знакоперемінних контактних навантажень, нагрів при тривалому гальмуванні та корозійні фактори викликають пошкодження рейок. Більшість дефектів рейок, що призводять до виходу їх з ладу, мають контактно-втомне походження і їх утворення часто пов'язано з металургійною якістю сталі, покращення якої потребує технологічних вдосконалень вздовж всього циклу виробництва рейок. Бібліогр. 25, іл. 1. К л ю ч о в і с л о в а : залізничні рейки; швидкість руху; навантаження на вісь; умови експлуатації; дефекти втомного походження

Experimental and numerical comparisons of mass transfer processes during the electroslag remelting with consumable electrode (ESR) and electroslag refining with liquid metal (ESR LM) showed their identical refining capacity, despite the smaller both the slag–metal contact surface (twice) and metal overheat (by 70–95 K) in the latter case. As revealed, due to effect of metal movement inside the liquid metal drop, it moves in liquid slag faster than a solid particle of the same diameter. Under comparable conditions, it is experimentally confirmed that desulphurization at the ESR takes place mainly on the contact surface between the slag and metal baths, but not in the liquid metal film at the tip of a consumable electrode.