The Plastic Flow of Surface Metal Layers

1971 ◽  
Vol 38 (4) ◽  
pp. 861-864
Author(s):  
J. H. L. The´ ◽  
R. F. Scrutton
Keyword(s):  
Plastic Deformation ◽  
Plastic Flow ◽  
Thermal Conduction ◽  
Metal Cutting ◽  
Plastic Layer ◽  
Approximate Analysis ◽  
Cold Surface ◽  
Surface Metal ◽  
Thin Plastic ◽  
Metal Layers

Various aspects of the plastic deformation of metals adjacent to the surfaces of tools or dies are discussed. The influence of thermal conduction between the thin plastic layer and the hot or cold surface of the tool or die is considered, while an approximate analysis is presented of the variation in the overall thickness of the layer at the chip-tool interface in metal cutting.

Thermal Analysis of Metal Flow at the Chip-Tool Interface in Metal Cutting

1967 ◽  
Vol 89 (3) ◽  
pp. 539-542 ◽  
Author(s):  
R. F. Scrutton
Keyword(s):  
Thermal Analysis ◽  
Shear Stress ◽  
Equation Of State ◽  
Boundary Layers ◽  
Metal Cutting ◽  
Metal Flow ◽  
Plastic Layer ◽  
Mechanical Equation ◽  
Thin Plastic ◽  
Viscous Boundary

The plastic flow of metal adjacent to the chip-tool interface is analyzed using a mechanical equation of state, which relates the variables stress, strain, strain rate, and temperature. Expressions are derived for the temperature at points within the thin plastic layer. The assumptions, which are similar to those used in the theory of viscous boundary layers, include the hypothesis that the shear stress is constant throughout the layer.

MANUFACTURE INVESTIGATION OF CARTRIDGE WITH BOTTOM-MOST PART FLANGE BY DIRECT EXTRUSION WITH COUNTERPUNCH. REPORT 13. DETERMINATION OF DEFORMED STATE UNDER STRAITENED EXTRUSION IN FOURTH CENTRAL AREA OF PLASTIC DEFORMATION

2020 ◽  
Vol 0 (4) ◽  
pp. 43-51
Author(s):  
A. L. Vorontsov ◽  
◽  
I. A. Nikiforov ◽  
Keyword(s):  
Plastic Deformation ◽  
Plastic Flow ◽  
Central Area ◽  
Direct Extrusion ◽  
Deformed State ◽  
Cumulative Deformation ◽  
The Given ◽  
General Method

Formulae have been obtained that are necessary to calculate cumulative deformation in the process of straitened extrusion in the central area closed to the working end of the counterpunch. The general method of plastic flow proposed by A. L. Vorontsov was used. The obtained formulae allow one to determine the deformed state of a billet in any point of the given area. The formulae should be used to take into account the strengthening of the extruded material.

Study on Evolution of Plastic Deformation of Brass Band under Impact Load

2017 ◽  
Vol 753 ◽  
pp. 222-227
Author(s):  
Jun Hui Yin ◽  
Chao Xiong ◽  
Hui Yong Deng ◽  
Yan Long Zhang
Keyword(s):  
Plastic Deformation ◽  
Growth Stage ◽  
Impact Load ◽  
Recrystallization Process ◽  
Brass Band ◽  
Sexual Characteristics ◽  
Surface Metal ◽  
Band Deformation ◽  
The Impact ◽  
Meso Scale

During the moving stage of the projectile, the impact load produced by the detonation of the explosive powder acts on the ribbon, causing the plastic band deformation to occur rapidly and the surface temperature rapidly increases. In this paper, the evolution mechanism of the plastic deformation of brass band is studied, and the recrystallization process of the surface metal is still at the meso-scale scale. The recrystallization and grain growth stage sexual characteristics.

Plastic Flow of Aluminum in Explosive Welding

2019 ◽  
Author(s):  
V.G. Petushkov ◽  
M.I. Zotov ◽  
L.D. Dobrushin
Keyword(s):  
Plastic Deformation ◽  
Corrosion Resistance ◽  
Plastic Flow ◽  
Explosive Welding ◽  
High Speed ◽  
Contact Point ◽  
Contact Boundary ◽  
High Speed Collision ◽  
Collision Angle

Joining of metals in explosive welding takes place as a result of their plastic deformation during a high speed collision and is usually accompanied by typical formation of waves at the interface. In welding aluminium, the weld boundary can also be straight if the speed of the contact point is νc is ≤ 1900 m/s. These welding conditions make it possible to prevent melting of the metal at the interface and increase at the same time its corrosion resistance. In this article, the effect of the dynamic collision angle on the special features of plastic flow of the metal in the vicinity of the contact boundary in welding sheets of AS5 aluminium is described.

scholarly journals Simulation of plastic deformation and destruction in the process of chip formation

2018 ◽  
Vol 211 ◽  
pp. 17007
Author(s):  
Tanel Tärgla ◽  
Jüri Olt ◽  
Olga Liivapuu
Keyword(s):  
Plastic Deformation ◽  
Formation Process ◽  
Chip Formation ◽  
Rheological Model ◽  
Metal Cutting ◽  
Depth Of Cut ◽  
Key Factors ◽  
Local Zone ◽  
Complex Process ◽  
Relaxing Medium

Metal cutting is a complex process in which several mechanisms are at work simultaneously. The mathematical modelling allows carrying out research into the optimization of machining conditions. This work examines the simulation of chip formation during the process of cutting. The studies demonstrated that the chip formation process, taking into account the plastic deformation and destruction of metal in the local zone, is most appropriately represented by a rheological model in the form of a series connection of elasticductile- plastic relaxing medium of Ishlinskiy (reflecting the process of primary deformation of metal from the cut off layer) and the medium of Voigt with two elastic-dissipative elements (representing the process of deformation and frictions from the convergent shaving). The attained complex rheological model served as the basis for constructing a representative dynamic model for the chip formation process. The key factors that govern the chip formation have been taken into account, such as tool vibration frequency and amplitude, depth of cut, feed rate.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. MECHANICAL AND MATHEMATICAL ANALYSIS OF THE FOURTH AND FIFTH VARIANTS OF THE PROCESS

2021 ◽  
pp. 2-12 ◽  
Author(s):  
A. L. Vorontsov ◽  
D. A. Lebedeva
Keyword(s):  
Plastic Deformation ◽  
Plastic Flow ◽  
Mathematical Analysis ◽  
Mathematical Study ◽  
Successful Design ◽  
Conical Bottom

Using the general methods of A. L. Vorontsov, a mechanical and mathematical study of the fourth and fifth variants of the process of combined extrusion of glasses with a conical bottom was carried out. All necessary design schemes are presented. Calculation formulas have been obtained that make it possible to determine the deformation forces and the magnitude of the plastic deformation areas for each possible variant of the plastic flow of the workpiece metal. These formulas also make it possible to determine which variant of deformation will occur in a particular case, and are necessary for the successful design of this operation. The results of confirming experiments are presented.

COMPREHENSIVE INVESTIGATION OF EXTRUSION OF П-SHAPED BRACKETS. REPORT 6. KINEMATIC AND STRESSED STATES OF BLANKET DURING RESTRICTED EXTRUSION. PART 2

2021 ◽  
pp. 38-43
Author(s):  
A. L. Vorontsov ◽  
◽  
S. M. Karpov ◽  
Keyword(s):  
Plastic Deformation ◽  
Plastic Flow ◽  
Plane Deformation ◽  
Flow Theory ◽  
Equation System ◽  
Extrusion Process ◽  
Thick Wall ◽  
Comprehensive Investigation ◽  
Flow Velocities

On the basis of the complete equation system of the plastic flow theory, the solution continuation of the determination problem of the kinematic and stressed states of a blanket during restricted extrusion of П-shaped brackets under conditions of plane deformation in the general case of a nonaligned placement of the punch and the die is stated. The determination of flow velocities and stresses in the area of plastic deformation, located under the punch end near the formed thick wall of the bracket has been carried out. The formulae were obtained, which are required for identification of the main parameters of the extrusion process of П-shaped products with a relatively thin horizontal bridge.

scholarly journals PLASTIC DEFORMATION OF THICK-WALLED SNOW-ICE CYLINDERS UNDER HYDROSTATIC PRESSURE

1962 ◽  
Vol 40 (10) ◽  
pp. 1310-1318 ◽  
Author(s):  
H. H. G. Jellinek
Keyword(s):  
Activation Energy ◽  
Plastic Deformation ◽  
Hydrostatic Pressure ◽  
Strain Rate ◽  
Plastic Flow ◽  
Constant Pressure ◽  
Circumferential Stress ◽  
Sine Function ◽  
Kcal Mole ◽  
Flow Process

The results of experiments on the plastic deformation of hollow snow-ice cylinders, closed at one end, as a function of circumferential stress and temperature are discussed. Data are graphed on deformation as a function of time for a snow-ice cylinder under 7.03 and 14.06 kg/cm2 hydrostatic pressure at −4.5 °C, deformation as a function of hydrostatic pressure from 2.11 to 7.03 kg/cm2, and deformation as a function of temperature at a constant pressure of 10.55 kg/cm2. The natural strain rate of closure at constant circumferential stress and temperature was a constant, which varied with circumferential stress as a sine function and was "exponentially dependent on temperature, with an activation energy of 14.1 kcal/mole at an average circumferential stress of 3.1 kg/cm2. The experiments agree well with an earlier interpretation of the plastic flow process representing flow between grain boundaries.

The Realities of Friction in Metal Plastic Flow With Corresponding Results During Metal Cutting

2019 ◽  
Author(s):  
Wolfgang Lortz ◽  
Radu Pavel
Keyword(s):  
Internal Friction ◽  
Strain Rate ◽  
Plastic Flow ◽  
Cross Sections ◽  
Chip Formation ◽  
Metal Cutting ◽  
Material Behavior ◽  
Deformation Pattern ◽  
Low Velocity ◽  
As Stress

Abstract Metal cutting is a dynamic process with two types of friction: on the one hand, external friction between two different bodies, and on the other hand, an internal friction inside the same material, due to plastic flow. These two different types of friction lead to different chip formation processes. In the case of built-up-edge (BUE), low velocity creates low energy, resulting in a self-hardening effect with BUE. With increasing velocity, the energy will increase and will result in high temperatures with a built-up-layer (BUL). Furthermore, under special circumstances, friction will lead to a self-blockade (a self-blocking state). This situation describes the third stage in metal plastic flow — the creation of a segmental chip. In this case the internal friction takes over. One question arises: “How can we determine these two types of different friction?” For solving these phenomena new fundamental equations based on mathematics, physics and material behavior have to be developed. This paper presents newly developed equations, which deliver the theoretical distribution of yield shear stress as well as strain rate with corresponding grid deformation pattern in metal plastic flow. For an actual cut, the plastic deformation pattern remains when the process is stopped, and therefore the theoretical result can be compared with cross-sections of the relevant chip formation areas — contrary to outputs such as stress, strain rate and temperatures which are all functions of position and time. All this will be shown and discussed in the paper, and stands in good agreement with experimental results.

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