Influence of melt treatment parameters on the characteristics of modified cast iron in the metallurgical industry using data mining methods

Denis Boldyrev,Alexey Nedelkin,Vitalii Emelianov,Oleg Latypov,Roman Dema,Anton Zhilenkov

doi:10.15587/1729-4061.2021.229642

Abstract

A study of the effect of holding the cast iron melt at temperatures of 1,300, 1,450 and 1,600 °C for 20, 55 and 90 minutes on the structure and properties of cast iron in a liquid state and after crystallization was carried out. The studies were carried out on samples with a diameter of 30 mm; cast iron containing 3.61–3.75 % carbon, 1.9–2.4 % silicon, 0.03 % manganese, 0.081–0.084 % phosphorus, 0.031–0.039 % sulfur was poured into green-sand molds. The samples were cast from the original cast iron (unmodified), modified with ferrosilicon 75 GOST 1415-93 (FS75), rare-earth metals (REM) and together with the REM+FS75 complex. The structure of cast iron was investigated by optical metallography, electron microscopy and X-ray structural analysis. An increase in the holding temperature and time of the cast iron melt leads to an increase in its hardness. An increase in temperature at a short holding time leads to an increase in strength in the entire investigated temperature range (1,300–1,600 °С). Holding for 90 minutes at a temperature of 1,450 °C corresponds to an extremum, after which, with a further increase in temperature, a sharp drop in strength is observed. The change in the toughness of cast iron is characterized in a similar way

Highlights

Cast iron is widely used in mechanical engineering despite the constant appearance of new functional and structural materials
– the optimal conditions for the formation of vermicular graphite is the modification of cast iron with the REM+FS75 complex at a melt holding temperature of 1,450 °C and time of 20 minutes;
– an increase in the holding temperature and time of the cast iron melt modified with REM additives leads to an increase in ledeburite in the structure;

Summary

Introduction

Cast iron is widely used in mechanical engineering despite the constant appearance of new functional and structural materials. One of the main directions in controlling the structure and improving the mechanical properties of cast iron castings is melt processing. The most common methods of influencing the liquid state of cast iron are heat-time treatment (HTT), melt modification and secondary refining [2, 3]. A promising direction of influence on crystallization processes, and through them on the structure and properties of cast iron castings, is heat-time treatment of the alloy in the liquid state before pouring. The large variability of the influence of holding parameters (temperature and time) with the use of various modifiers on the structure and properties of lamellar iron castings represents a huge field of study

Objectives

Methods

Conclusion