Effect on Flow Stress of a Rapid Phase Transition in AISI 1045 Steel

Author(s):  
Timothy J. Burns ◽  
Steven P. Mates ◽  
Richard L. Rhorer ◽  
Eric P. Whitenton ◽  
Debasis Basak

New experimental data on AISI 1045 steel from the NIST pulse-heated Kolsky Bar Laboratory are presented. The material is shown to exhibit a nonequilibrium phase transformation at high strain rate. An interesting feature of these data is that the material has a stiffer response to compressive loading when it has been preheated to a testing temperature that is below the eutectoid temperature using pulse-heating than it does when it has been preheated using a slower heating method. On the other hand, when the material has been pulse-heated to a temperature that exceeds the eutectoid temperature prior to compressive loading on the Kolsky bar, it is shown to exhibit a significant loss of strength. A consequence of this behavior is that fixed-parameter constitutive models, such as the well-known Johnson-Cook model, cannot be used to describe this constitutive response behavior. An argument is made that the phase transition does not occur during high-speed machining operations, and suggestions are made as to how to modify the Johnson-Cook model of Jaspers and Dauzenberg for this material in order to obtain improved temperature predictions in finite-element simulations of high-speed machining processes.

2017 ◽  
Author(s):  
Xingbang Chen ◽  
Nick H. Duong ◽  
J. Ma ◽  
Shuting Lei

In this paper, numerical investigation of the effects of microgroove textured cutting tools in high speed machining of AISI 1045 is conducted using Finite Element Method (FEM). Microgrooves are designed and fabricated on the rake face of cemented carbide (WC/Co) cutting inserts. The effects of microgroove width, edge distance (the distance from cutting edge to the first microgroove), and microgroove depth are examined and assessed in terms of main cutting force, thrust force, and tool-chip contact length. It is found that microgrooved cutting tools generate lower cutting force and consequently lower the energy necessary for machining. This research provides insightful guidance for optimizing tool life and reducing energy consumption in high-speed machining of AISI 1045 steel.


Author(s):  
Han Wu ◽  
Nick H. Duong ◽  
J. Ma ◽  
Shuting Lei

In this paper, the commercial FEM software package Abaqus is used to investigate the effects of microgrooved cutting tools in high speed orthogonal cutting of AISI 1045 steel. Microgrooves are designed and fabricated on the rake face of cemented carbide (WC/Co) cutting inserts. A coupled Eulerian-Lagrangian (CEL) finite element model is developed based on Abaqus to solve the evolution of the cutting temperature, chip morphology, cutting force, and phase constitutes simultaneously. This model is validated by comparing the numerical results with the experimental data for orthogonal high speed cutting of AISI 1045 steel with various cutting conditions. In addition, this model is also validated by comparing with the experimental data of regular tool and microgrooved cutting tool under the cutting speed of 120m/min. This validated CEL FEM model is then utilized to investigate the effects of microgrooved cutting tools on the phase transformation, cutting force, cutting temperature, and chip morphology in high speed orthogonal cutting of AISI 1045. The effects of microgroove width, edge distance (the distance from cutting edge to the first microgroove), and microgroove depth are examined and assessed in terms of cutting force, cutting temperature, chip morphology, and phase transformation. It is found that this CEL FEM model can capture the essential features of orthogonal high speed cutting of AISI 1045 using microgrooved cutting tools. It is also concluded that microgrooved cutting tools can not effectively reduce the cutting force in high speed machining, which is contrary to the conclusion obtained for low speed machining in previous research. However, microgrooves on the rake face have influence on the austenite percentage in the chip near the rake face. This research provides insightful guidance for optimizing the cutting performance in terms of cutting temperature, cutting force, chip morphology, and phase transformation in high speed machining of AISI 1045 steel.


2011 ◽  
Vol 308-310 ◽  
pp. 1134-1138 ◽  
Author(s):  
Su Yu Wang ◽  
Wen Chao Wang ◽  
Tao Yu ◽  
Bin Jiang

Surface roughness is an important parameter to evaluate the quality of high-speed machining (HSM). This paper establishes a mechanical model based on the molecular-mechanical theory of friction to study factors that influence the surface roughness in HSM. The relationship between flow stress and the remnant height on the machined surface is obtained. The HSM process of AISI-1045 steel is simulated by using finite element method (FEM) based on DEFORM-2D and the flow stress is obtained. The surface roughness of workpiece machined by HSM is calculated based on the value of flow stress and the mechanical model. The result shows that the surface roughness of workpiece in HSM is acceptable, and the mechanical model supplies a method to study the surface roughness in HSM.


1984 ◽  
Vol 106 (3) ◽  
pp. 242-247 ◽  
Author(s):  
A. Thangaraj ◽  
P. K. Wright ◽  
M. Nissle

Using metallographic and microhardness techniques, temperature distributions have been determined in twist drills. The methods rely on the fact that certain high speed steel materials exhibit microstructural changes when subjected to temperatures greater than 600°C. Quick-stop specimens have also been obtained to study the metal flow patterns over the drill flutes. These results have been used to comment on the different wear mechanisms that affect the performance of a twist drill. Preliminary results show that bulk plastic flow occurs near the margin of the drill where the temperatures are in the vicinity of 900°C when machining AISI 1045 steel at 40 m/min.


2016 ◽  
Vol 861 ◽  
pp. 63-68 ◽  
Author(s):  
Xue Ping Zhang ◽  
Shu Biao Wu ◽  
Zhen Qiang Yao ◽  
Li Feng Xi

Hardened AISI 1045 steel implemented in machine tool spindle was previously ground using grinding operation. This research aims to address the feasibility of hard turning AISI 1045 using PCBN tool with chip breaker under dry condition. Chip morphology, cutting force and temperature were measured, analyzed and correlated with machining parameters. Experimental results demonstrate that serrated chips are generated at high speeds, high feed rate is an assistant to promote serrated chips, and chip breaker can help break chip into acceptable lengths. Cutting forces were characterized with periodic fluctuation along three directions as chips are serrated. Temperature at machined zone can reach as high as 1200°C, which indicates that adiabatic shear bands can be successfully achieved during the machining of hardened AISI 1045 steel without applying lubricants.


2018 ◽  
Vol 2 (4) ◽  
pp. 66 ◽  
Author(s):  
Luis Hernández González ◽  
Yassmin Seid Ahmed ◽  
Roberto Pérez Rodríguez ◽  
Patricia Zambrano Robledo ◽  
Martha Guerrero Mata

The manufacturing industry aims to produce many high quality products efficiently at low cost, thereby motivating companies to use advanced manufacturing technologies. The use of high-speed machining is increasingly widespread; however, it lacks a deep-rooted knowledge base needed to facilitate implementation. In this paper, response surface methodology (RSM) has been applied to determine the optimum cutting conditions leading to minimum flank wear in high-speed dry turning on AISI 1045 steel. The mathematical models in terms of machining parameters were developed for flank wear prediction using RSM on the basis of experimental results. The high speed turning experiments were carried out with two coated carbide and a cermet inserts using AISI 1045 steel as work material at different cutting speeds and machining times. The models selected for optimization were validated through the Pareto principle. Results showed the GC4215 insert to be the most optimal option, because it did not reach the cutting tool life limit and could be used for the whole range of cutting parameters selected. To quantitatively evaluate the usefulness of the cutting tools, it was proposed the coefficient of use of the tools from the results of the contour graphs. The GC4215 insert showed 100% effectiveness, followed by the GC4225 with 98.4%, and finally, the CT5015 insert with 83%.


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