Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
EVALUATION OF THE MECHANICAL BEHAVIOR OF STEELS USED IN THE SLIDE RING OF A BALL MILL OF AN IRON ORE MINING PLANT
Submission Author:
Leonardo Godefroid , MG
Co-Authors:
Claudinei Roberto Guimarães, Leonardo Godefroid, Luiz Cláudio Cândido, Sidney Araújo
Presenter: Leonardo Godefroid
doi://10.26678/ABCM.COBEM2019.COB2019-0155
Abstract
This work identified the root cause of an early failure occurring in the slide ring of a ball mill used in an iron mining plant. The steel employed at this location met the ASTM-A516-G60 specification for use in pressure vessels and similar structures. However, the microstructure presented by this steel consisted of a totally heterogeneous distribution of ferrite grains and pearlite colonies, with variations in grain size and volume fraction. This microstructure led to the development of fatigue cracks that crossed the thickness of the slide ring. As a consequence, the iron ore pulp has been contaminated with the lubricating oil, decreasing the adequate oil level and generating excessive wear on bearings and loss of pressure from the lubrication system. All these facts made impracticable the operation of the mill. Three different steels that also meet the specification for application in pressure vessels were analyzed and compared with the failed steel by means of tension, Rockwell hardness, Charpy impact, fracture toughness (J-R curves) and fatigue tests (σa-Nf curves and da/dN x ΔK curves). It was concluded that the material selection for the mill component must take into account its sensitivity to high temperatures from a welding process, in order to guarantee a microstructure and a minimum of mechanical resistance compatible with its use.
Keywords
failure analysis, Fatigue cracking, Ball mill, Structural steels
