Metallurgy of Highly Wear-Resistant Indefinite-Chill Work Roll Materials for Hot Rolling Mills

2021 ◽  
Vol 1016 ◽  
pp. 1085-1090
Author(s):  
Armin Paar ◽  
Michael Aigner ◽  
Coline Beal ◽  
Christof Sommitsch
Keyword(s):  
Wear Resistance ◽  
Hot Rolling ◽  
Work Roll ◽  
Matrix Elements ◽  
Tempered Martensite ◽  
Wear Resistant ◽  
Rolling Mills ◽  
Cementite Phase ◽  
Low Sensitivity ◽  
Work Rolls

Indefinite-chill materials are used as shell materials for cast work rolls for surface-critical applications in hot rolling mills. Besides a smooth surface quality, a low sticking tendency and low sensitivity against incidents in the rolling mill, the work rolls need the highest wear resistance possible. The microstructure of the indefinite-chill material consists of various carbides (cementite up to 40 area-%) and up to 5 area-% of graphite embedded in tempered martensite. To increase the wear resistance of this material group, the comparably soft cementite has to be replaced by more wear resistant carbides such as MC, M2C or M6C. This can be achieved by increasing the amount of carbide forming elements such as Nb, V, Mo, W or Cr. Nevertheless it is important to maintain a certain amount of graphite in the microstructure to avoid sticking to the rolled material and to lower the sensitivity against mill incidents. It is well known that high amounts of carbide forming elements limit the graphite precipitation and therefore a sophisticated alloying concept is required for this material type. Not only the effects of matrix elements such as Si, Mn, Ni and Co but also the effects of Cr, Mo, W, Nb and V were studied in an intensive research project. This work gives an insight in the results of the project based on the example of the effects of Si and Cr on the phase amounts and the composition of the cementite phase.

Thermal-fatigue resistant work rolls for hot rolling mills

2019 ◽  
Vol 61 (5) ◽  
pp. 397-404
Author(s):  
Vyacheslav Goryany ◽  
Olga Myronova ◽  
Johannes Buch ◽  
Alexander Buch ◽  
Frank Stein
Keyword(s):  
Thermal Fatigue ◽  
Hot Rolling ◽  
Rolling Mills ◽  
Work Rolls

scholarly journals Finite elements prediction of thermal stresses in work roll of hot rolling mills

2010 ◽  
Vol 2 (1) ◽  
pp. 707-716 ◽  
Author(s):  
D. Benasciutti ◽  
E. Brusa ◽  
G. Bazzaro
Keyword(s):  
Finite Elements ◽  
Hot Rolling ◽  
Thermal Stresses ◽  
Work Roll ◽  
Rolling Mills

scholarly journals Coupled Vibration Characteristics Analysis of Hot Rolling Mill with Structural Gap

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Guangxu Zhang ◽  
Jiahan Bao ◽  
Wenhao Li ◽  
Zhichong Wang ◽  
Xiangshuai Meng
Keyword(s):  
Hot Rolling ◽  
Rolling Mill ◽  
Process Model ◽  
Elastic Recovery ◽  
Rolling Force ◽  
Excitation Amplitude ◽  
Work Roll ◽  
Rolling Process ◽  
Structure Model ◽  
Rolling Mills

It is important to study the vibration of rolling mills to improve the stability of rolling production. A dynamic rolling process model is established by considering the elastic recovery of the exit strip and the influence of multiroll equilibrium, and the accuracy of the model is verified by experimental data. On this basis, based on the distribution of friction force in the deformation zone, the rolling force and rolling torque are nonlinearized. In addition, a rolling mill structure model is established by considering the structure gap and a piecewise nonlinear horizontal-vertical-torsional vibration model of the rolling mill is established by combining the structure model and dynamic rolling process model. Finally, the amplitude-frequency characteristics of the work roll under different external excitation amplitude and the dynamic bifurcation characteristics of the work roll under different gaps are analyzed. The study indicates that, by reducing excitation amplitude and structure gap, the system vibration can be reduced. The research results can provide a theoretical reference for further exploration of the coupling vibration of hot rolling mills.

An Investigation of the Effect of Speeds of Work Rolls on Rolling Strip

1995 ◽  
Vol 117 (3) ◽  
pp. 341-346 ◽  
Author(s):  
Zone-Ching Lin ◽  
Y. C. Cheng
Keyword(s):  
Hot Rolling ◽  
Rolling Force ◽  
Large Strain ◽  
Work Roll ◽  
Rolling Process ◽  
Analysis Model ◽  
Hot Rolling Process ◽  
Rolling Strip ◽  
Work Rolls ◽  
Thermoelastic Plastic

The paper is an investigation of strip curvature caused by the different speeds between the upper work roll and the lower work roll in the rolling process for an aluminum strip. At the same time, we analyzed the variations in the temperature field and strain field, and used a method of speeds variation of the upper and lower work rolls to calibrate the deformation curvature caused by the coolant condition in the hot rolling process. Based on the large deformation-large strain theory, and by means of the Updated Lagrangean Formulation (ULF) and increment theory, a coupled thermoelastic-plastic analysis model for hot rolling process is thus constructed. At the same time the finite difference method was also used to solve the transient heat transfer equation. Finally, the numerical analysis method developed in this study was employed to analyze the changes in the aluminum strip’s temperature and other changes during rolling. In addition, the average rolling force obtained from the simulation was compared with that from the experiments. It verified that the model in this study is reasonable.

Stress due to interfacial slip causing sleeve fracture in shrink-fitted work roll

2021 ◽  
pp. 2140020
Author(s):  
Nao-Aki Noda ◽  
Rahimah Abdul Rafar ◽  
Yoshikazu Sano
Keyword(s):  
Fatigue Strength ◽  
Hot Rolling ◽  
Work Roll ◽  
Relative Displacement ◽  
The Other ◽  
Interfacial Slip ◽  
Sleeve Fracture ◽  
Construction Type ◽  
Work Rolls ◽  
Solid Type

The rolls are classified into two types; one is a single-solid type, and the other is a shrink-fitted construction type consisting of a sleeve and a shaft. The bimetallic work rolls are widely used in the roughing stands of hot rolling stand mills. Regarding a shrink-fitted construction type, the interfacial slip sometimes appears between the shaft and the shrink-fitted sleeve. This interfacial slip can be regarded as the relative displacement between the sleeve and the shaft. In this paper, the stress due to the interfacial slip is studied because the stress may cause the sleeve fracture. It is found that the stress in the shrink-fitted surface is slightly decreased with increasing number of rotations [Formula: see text]. Therefore, the stress obtained by the simulation at [Formula: see text] can be used to estimate the fatigue strength.

scholarly journals Experimental study of horizontal impact forces acting on equipment of thick sheet rolling stands during rolling

2018 ◽  
Vol 239 ◽  
pp. 01041 ◽  
Author(s):  
Anatoliy Ishchenko ◽  
Viktor Artiukh ◽  
Vladlen Mazur ◽  
Albina Calimgareeva ◽  
Miroslava Gusarova
Keyword(s):  
Experimental Data ◽  
Experimental Studies ◽  
Work Roll ◽  
Thick Sheet ◽  
Sheet Rolling ◽  
Technical Aspects ◽  
Rolling Mills ◽  
Impact Forces ◽  
Technical Solutions ◽  
Work Rolls

Technical aspects, methods and results of experimental studies of reversing rolling stands details horizontal accelerations of thick sheet rolling mills 3000 and 3600 are shown. Sequence of horizontal movements of bottom work roll with chocks in windows of housings during normal metal-in, steady rolling and metal-out is given. Usage of obtained experimental data and calculation of horizontal forces of work rolls chocks impacts against housings provided execution of stress calculations of technical solutions for increase of rolling stands durability.

scholarly journals On the Evolution of Temperature and Combined Stress in a Work Roll under Cyclic Thermo-Mechanical Loadings during Hot Strip Rolling and Idling

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5054
Author(s):  
Kejun Hu ◽  
Qinghe Shi ◽  
Wenqin Han ◽  
Fuxian Zhu ◽  
Jufang Chen
Keyword(s):  
Thermal Stress ◽  
Hot Rolling ◽  
Work Roll ◽  
Rolling Process ◽  
Roll Surface ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Hot Strip ◽  
Calculation Results ◽  
Work Rolls

An accurate prediction of temperature and stress evolution in work rolls is crucial to assess the service life of the work roll. In this paper, a finite element method (FEM) model with a deformable work roll and a meshed, rigid body considering complex thermal boundary conditions over the roll surface is proposed to assess the temperature and the thermal stress in work rolls during hot rolling and subsequent idling. After that, work rolls affected by the combined action of temperature gradient and rolling pressure are investigated by taking account of the hot strip. The accuracy of the proposed model is verified through comparison with the calculation results obtained from the mathematical model. The results show that thermal stress is dominant in the bite region of work rolls during hot rolling. Afterwards, the heat treatment residual stresses which are related to thermal fatigue are simulated and introduced into the work roll as the initial stress to evaluate the redistribution under the thermal cyclic loads during the hot rolling process. Results show that the residual stress significantly changed near the roll surface.

A Study of Abrasive Wear on High Speed Steel Surface in Hot Rolling

2016 ◽  
Vol 846 ◽  
pp. 589-594 ◽  
Author(s):  
T. Hoang Phan ◽  
Ahn Kiet Tieu ◽  
Hong Tao Zhu ◽  
Bu Yung Kosasih ◽  
Qiong Wu ◽  
...  
Keyword(s):  
Abrasive Wear ◽  
Hot Rolling ◽  
High Speed ◽  
High Speed Steel ◽  
Work Roll ◽  
Contact Friction ◽  
Strip Surface ◽  
Debris Slide ◽  
Physically Based ◽  
Work Rolls

In hot rolling, the thermal cyclic of work rolls causes a superficial oxide scale, which plays an important role on the contact friction and wear. The asperities of oxidised strip surface and wear debris slide over the High Speed Steel (HSS) work roll surface which comprises of hard carbides within an iron matrix under high pressure and velocity. Abrasive wear occurs and the particles will be removed from HSS surface. The current study introduces the Discrete Element Method (DEM) to investigate this abrasive wear phenomenon. The model successfully provides a physically based abrasive roll wear predication of HSS work roll with the consideration of carbides and oxide layers. It has been found that the carbide shape in the HSS roll affects the wear significantly, which has not been reported by previous numerical simulations and is the main focus of this research.

Thermal Behavior of Aluminum Rolling

1990 ◽  
Vol 112 (2) ◽  
pp. 301-308 ◽  
Author(s):  
A. A. Tseng ◽  
S. X. Tong ◽  
S. H. Maslen ◽  
J. J. Mills
Keyword(s):  
Heat Transfer ◽  
Aluminum Alloys ◽  
Hot Rolling ◽  
High Speed ◽  
Critical Factor ◽  
Work Roll ◽  
Operating Parameters ◽  
Temperature Profiles ◽  
Rolling Mills ◽  
Heat Transfer Theory

Proper roll cooling has been identified as a critical factor in the problems of excessive roll spalling and poor thermal crowning in modern, high-speed rolling mills. In this paper, an analytical model has been developed to determine the temperature profiles of the roll and the strip. This model uses basic heat transfer theory and provides the capability of studying the influence of operating parameters on both the work-roll and workpiece temperatures. Examples on cold and hot rolling of aluminum alloys are given to demonstrate the feasibility and capability of the model developed. Previous work on thermal modeling of rolling processes is also briefly reviewed.

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