Inclusions Control and Refining Slag Optimization for Fork Flat Steel

Yangyang Ge,Bin Yang,Zushu Li,Shuo Zhao,Liang Ma,Tao Yan

doi:10.3390/met9020253

Yangyang Ge, Bin Yang + Show 4 more

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https://doi.org/10.3390/met9020253

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Abstract

In order to investigate the causes of the large number of cracks and porosities formed in 33MnCrTiB fork flat steel produced by a special steel plant, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) analysis, and large sample electrolysis of the obtained steel samples were carried out in different steps of the steelmaking processes. The main micro-inclusions in the fork flat steel samples were Al2O3, CaO-MgO-Al2O3-SiO2, and TiN, and the macro-inclusions were mainly Al2O3, CaO-Al2O3, CaO-Al2O3-SiO2-TiO2, and CaO-MgO-Al2O3-SiO2-TiO2-(K2O) systems which originated from the ladle slag and mold flux in the production process. In order to reduce the number of micro-inclusions effectively, the control range of components in the refining slag was confirmed by the thermodynamic calculation, where the mass ratio of CaO/Al2O3 should be in the range of 1.85–1.92, and the mass fraction of SiO2 and MgO should be controlled to 7.5–20% and 6–8%, respectively. In addition, the numbers of macro-inclusions in the flat steel should be effectively reduced by optimizing the flow field of mold and preventing the secondary oxidation, and the flat steel quality problems caused by the inclusions can be improved by the optimization process above.

Highlights

Forklift trucks are common production vehicles, which convey raw materials to the production line, scrap, and final products to the storage areas or to the transportation trucks
The research shows that the load-support parts of forklift forks are subjected to repetitive stress conditions of a variety of load and frequency spectra [1,2], including loading and unloading cycles and vibrations coming from moving on irregular terrain conditions [3,4]
In order to study the influence of inclusions on the straightening cracks of fork flat steel, we analyzed the inclusions in steel according to two sources of inclusions—exogenous and endogenous inclusions

Summary

Introduction

Forklift trucks are common production vehicles, which convey raw materials to the production line, scrap, and final products to the storage areas or to the transportation trucks. The fork is one of the most important parts of a forklift. It bears a large external force, and needs to be a small cross section and lightweight. The research shows that the load-support parts of forklift forks are subjected to repetitive stress conditions of a variety of load and frequency spectra [1,2], including loading and unloading cycles and vibrations coming from moving on irregular terrain conditions [3,4].

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