Heating Effects in the Drawing of Wire and Strip Under Hydrodynamic Lubrication Conditions

1996 ◽  
Vol 118 (4) ◽  
pp. 628-638 ◽  
Author(s):  
D. A. Lucca ◽  
R. N. Wright
Keyword(s):  
High Speed ◽  
Hydrodynamic Lubrication ◽  
Lubricant Film ◽  
Strip Surface ◽  
Heating Effects ◽  
Strip Drawing ◽  
Dimensional Parameters ◽  
Lubrication Conditions ◽  
Lubricant Viscosity

The use of high metal processing speeds to meet the demands for increased productivity has focused attention on the pronounced heating of tooling and workpiece which occurs under these conditions. In the present study, heating under hydrodynamic conditions in wire and strip drawing is addressed by considering a two-dimensional representation of the tool-lubricant-workpiece interface. An analytical formulation is presented for prediction of the resultant temperatures. The model considers deformation heating in the strip, lubricant viscosity to be a function of temperature and pressure, and matches the heat flux at the strip-lubricant boundary. Convection of heat in the lubricant film is considered. The model is constructed in terms of the governing non-dimensional parameters and solved by a Crank-Nicolson finite difference technique. By comparison with solutions which do not consider convection, it is found that convection only begins to play a role in the resulting temperatures when the Graetz number U0h02/αLl is greater than 0.4. For the high speed drawing of aluminum with mineral oil used as a lubricant, the model predicts a monotonic increase in mean lubricant temperatures from 366 K to 404 K over a range of initial strip velocities of 20.3 m/s to 50.8 m/s. The maximum strip surface temperature is predicted to monotonically decrease from 345 K to 335 K over this range of strip velocities. The ratio (kLρLcpL/ksρscpS)1/2 is shown to be important in determining the relative temperatures of lubricant and strip. Results are compared to those metalworking analyses which do not consider the role of the lubricant film.

An Experimental Investigation of Surface Pit Evolution During Cold-Rolling or Drawing of Stainless Steel Strip

2000 ◽  
Vol 123 (1) ◽  
pp. 1-7 ◽  
Author(s):  
R. Ahmed ◽  
M. P. F. Sutcliffe
Keyword(s):  
Experimental Investigation ◽  
Stainless Steel ◽  
Hydrodynamic Lubrication ◽  
Steel Strip ◽  
Similar Rate ◽  
Steel Strips ◽  
Strip Drawing ◽  
Hot Band ◽  
Cold Rolled

This paper presents an experimental investigation of the mechanisms of pit elimination in strip drawing and rolling of stainless steel strips. Strip drawing tests with artificial indents confirm the role of micro-plasto-hydrodynamic lubrication (MPHL) in allowing pits to be reduced in size and depth. The similarity of results for two oils, which differ in viscosity by a factor of 10, is attributed to the fact that oil is drawn out of the pits rather easily, so that the behavior tends to the unlubricated case. Similar behavior is observed for strip drawing of shot blast white hot band. For much smoother bright anneal strip, it is suggested that the presence of an oil film in the unpitted region prevents generation of pressure differences between the pits and the unpitted regions. A comparison of strip-drawn and cold-rolled stainless steel samples show that the change in pit area and Rq roughness varies with overall reduction in a remarkably similar way. The reason for such similar behavior is attributed to the absence of hydrodynamic action in preventing pit elimination, albeit for opposite reasons. The similar rate of pit evolution in both cases confirms the usefulness of the strip drawing rig as a tool to model the change of surface topography during rolling, as long as care is taken in matching the regimes of lubrication.

Loss of lubricant from oil-lubricated near-starved spherical roller bearings

1997 ◽  
Vol 211 (1) ◽  
pp. 51-66 ◽  
Author(s):  
V Wikström ◽  
B Jacobson
Keyword(s):  
High Speed ◽  
Roller Bearing ◽  
Lubricant Film ◽  
Outer Ring ◽  
Shaft Speed ◽  
Roller Bearings ◽  
Bearing Load ◽  
Lubricant Viscosity ◽  
Oil Type

The time to lubricant film breakthrough in an oil-lubricated spherical roller bearing has been measured using SKF Lubcheck for various settings of bearing load, outer ring temperature, shaft speed and oil type and viscosity. The bearings were lubricated once and then run to film breakthrough with the aim of estimating the lubricant losses under different conditions. The result of the experiments supports the theory of lubricant replenishment, and it is shown that high speed combined with high lubricant viscosity will shorten the time to film breakthrough.

Lubrication Phenomena in Spur Gears: Capacity, Film Thickness Variation, and Efficiency

1965 ◽  
Vol 87 (3) ◽  
pp. 655-663 ◽  
Author(s):  
R. Wayne Adkins ◽  
E. I. Radzimovsky
Keyword(s):  
Shear Stress ◽  
Film Thickness ◽  
Pressure Distribution ◽  
Power Loss ◽  
Hydrodynamic Lubrication ◽  
Thickness Variation ◽  
Spur Gears ◽  
Oil Film ◽  
Lubrication Conditions ◽  
Lubricant Viscosity

In this paper the oil film separating the mating surfaces of involute spur gears operating under hydrodynamic lubrication conditions is analyzed. This analysis surpasses previous analyses in as much as the actual motion of the involute profiles (rolling, sliding, and squeezing motion) and the total number of teeth engaged at any one time are considered. Expressions are derived for the pressure distribution, shear stress, and power loss in the oil film at any phase of tooth engagement. A method is developed by which these expressions can be applied to determine the film thickness at any instant and the power loss for a given load, speed, and lubricant viscosity.

Hydrodynamic Lubrication in Axisymmetric Stretch Forming—Part 1: Theoretical Analysis

1991 ◽  
Vol 113 (4) ◽  
pp. 659-666 ◽  
Author(s):  
W. R. D. Wilson ◽  
L. G. Hector
Keyword(s):  
Theoretical Model ◽  
Theoretical Analysis ◽  
Film Thickness ◽  
Sheet Metal ◽  
Newtonian Fluid ◽  
Hydrodynamic Lubrication ◽  
Lubricant Film ◽  
Previous Model ◽  
Stretch Forming ◽  
Lubricant Viscosity

An improved theoretical model for the hydrodynamic lubrication of axisymmetric, sheet metal stretch forming is presented. The infinite initial film thickness problem, encountered in a previous model, is removed by accounting for the squeeze action occurring during the initial stages of the process. Both isoviscous and thermoviscous theories are developed assuming that the lubricant is a Newtonian fluid. In the thermoviscous model, the lubricant viscosity is assumed to vary exponentially with temperature. The influence of plastic heating of the sheet on the entrainment and transport of the lubricant film is examined. The effects of variable punch speed are also investigated.

scholarly journals Modeling of Micro-Pit Evolution in Rolling or Strip-Drawing

2000 ◽  
Vol 123 (4) ◽  
pp. 791-798 ◽  
Author(s):  
M. P. F. Sutcliffe ◽  
H. R. Le ◽  
R. Ahmed
Keyword(s):  
Hydrodynamic Lubrication ◽  
Steel Strip ◽  
Viscosity Coefficient ◽  
Sliding Speed ◽  
Dimensional Group ◽  
Theoretical Predictions ◽  
Strip Drawing ◽  
Measured Change ◽  
Cold Rolled ◽  
Lubricant Viscosity

The micro-plasto-hydrodynamic lubrication (MPHL) model of pit evolution is extended to account for the variation of sliding speed and strain rate in rolling and drawing processes. Results show that all of the following factors are important: pit angle, lubricant viscosity and pressure viscosity coefficient, material yield stress and sliding speed. Theoretical predictions for the change in pit area during the deformation process are well correlated by a non-dimensional group of these parameters. The model agrees reasonably with the measured change in pit volume and area from drawing experiments on cold rolled stainless steel strip containing both artificial and stochastic roughness.

scholarly journals Selected Problems from the High-Carbon Steel Wire Drawing Theory and Technology

2014 ◽  
Vol 59 (2) ◽  
pp. 527-535 ◽  
Author(s):  
Z. Muskalski
Keyword(s):  
Carbon Steel ◽  
High Speed ◽  
Hydrodynamic Lubrication ◽  
Steel Wire ◽  
High Carbon Steel ◽  
Wire Drawing ◽  
High Carbon ◽  
Software Application ◽  
Multi Stage ◽  
Lubrication Conditions

Abstract Use of computer programs based on finite element methods for simulations of plastic working processes allows for their wider analysis. The theoretical studies presented in the paper, carried out using Drawing 2D, a specialized software application for modelling of the multi-stage drawing process, and their experimental verification have enabled a comprehensive analysis of many problems related to high-carbon steel wire drawing to be made, such as: drawing under hydrodynamic lubrication conditions, drawing with a change in the deformation direction, drawing with small final reductions, and high-speed drawing.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

scholarly journals The Interaction between the Sheet/Tool Surface Texture and the Friction/Galling Behaviour on Aluminium Deep Drawing Operations

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 979
Author(s):  
Alaitz Zabala ◽  
Lander Galdos ◽  
Chris Childs ◽  
Iñigo Llavori ◽  
Andrea Aginagalde ◽  
...  
Keyword(s):  
Lightweight Design ◽  
Severity Index ◽  
Tribological Behaviour ◽  
Die Surface ◽  
Tool Surface ◽  
Strip Drawing ◽  
Aluminium Sheets ◽  
Increased Susceptibility

The increasing demands for lightweight design in the transport industry have led to an extensive use of lightweight materials such as aluminium alloys. The forming of aluminium sheets however presents significant challenges due to the low formability and the increased susceptibility to galling. The use of tailored workpieces and controlled die roughness surfaces are common strategies to improve the tribological behaviour, whilst galling is still not well understood. This work is aimed at analysing the interplay between the sheet and tool surface roughness on the friction and galling performance. Different degrees of Electro Discharge Texturing (EDT) textures were generated in AA1050 material strips, and tooling presenting different polishing degrees were prepared. Strip drawing tests were carried out to model the tribological condition and results were corroborated through cup drawing tests. A new galling severity index (GSI) is presented for a quick and quantitative determination of both galling occurrence and severity. The present study underlines the key role of die topography and the potential of die surface functionalization for galling prevention.

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