Complex Technology of Obtaining Qualitative Castings of Machine-Building and Metallurgical Purpose

Processy litʹâ, 2019, Tom 134, №2, p.65-72

Abstract

Received 13.02.2019

UDK 621.74.669.131.622

To establish the possibility of an effective influence on the quality of castings at all stages of their production, the processes of blast furnace casting, alloying and nano-modification of casting melts were examined and tested. Investigation of a number of institutions and enterprises: NMetAU, IFM NASU, PJSC MK Azovstal, PJSC Dnipropetrovsk Rolling Roll Plant, PJSC ArcelorMittal Kryvyi Rig, Melitopol Motor and Kharkov machine-building plants. The most responsible castings were widely used in the national economy: crankshafts, cylinder castings, automotive castings of high-strength and gray cast iron, rolled chilled and chilled-magnesium rolls, cast-iron casting molds, grinding balls etc. The optimal parameters of the casting production technology were established: use in the mixture of low-sulfur iron brand ЛP7, alloying of casting melts with 0.2 % W or Nb, nano-modification with titanium carbonitride Ti(CN) for white iron castings and silicon carbide (SiC) – for gray iron castings, applying paste and highly dispersed material, containing nanomaterials, to cover the form in the places of occurrence of «hot cracks» for hardening the surface layer of the crystallized casting. An experimental industrial verification of complex technologies shows that during recrystallization at 200–300 0C, the rate of transformation decreases, which reduces the likelihood of «hair-like cracks». At observance of the recommended parameters of the integrated technology, operational durability is increased by 30 %, small balls – by 20 %, roll rejects decreased by 5 %, crankshaft and piston engines reject – by 20 %.