An Inverse Method for Investigating Deformation Zone Temperatures in Metal Cutting

1991 ◽  
Vol 113 (2) ◽  
pp. 129-136 ◽  
Author(s):  
D. A. Stephenson
Keyword(s):  
Deformation Zone ◽  
Inverse Method ◽  
Metal Cutting ◽  
Empirical Studies ◽  
Cutting Temperature ◽  
Steady State Temperature ◽  
Average Deformation ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Effective Source

A major obstacle in verifying metal cutting temperature models and including thermal variables in empirical studies is the experimental difficulty of measuring physically meaningful cutting temperatures. This is especially true for deformation or shear zone temperatures, which influence the mechanical properties of the work material. This paper describes an inverse method for investigating deformation zone temperatures in end turning tests on thin-walled tubes. The method is based on analytical solutions for the quasi-steady state temperature distributions in a thin-walled ring heated by a rotating temperature source and a thin-walled tube heated by a helically moving source; using these solutions, remote temperature measurements on the tube can be used to back-calculate an effective source temperature which corresponds physically to an average deformation zone temperature. The method has been used in a broad range of experiments on steel, brass, aluminum, and cast iron to verify cutting temperature models. Sample calculations and infrared thermograms from these experiments are used to illustrate the application of the method.

A comprehensive experiment-based approach to generate stress field and slip lines in cutting process

2021 ◽  
pp. 1-18
Author(s):  
Zheng-Yan Yang ◽  
Xiao-Ming Zhang ◽  
Guang-Chao Nie ◽  
Dong Zhang ◽  
Han Ding
Keyword(s):  
Stress Field ◽  
Deformation Zone ◽  
Metal Cutting ◽  
Transfer Problem ◽  
Maximum Shear Stress ◽  
Cutting Temperature ◽  
Cutting Process ◽  
Slip Lines ◽  
Strain And Strain Rate ◽  
Main Deformation

Abstract This study proposes a comprehensive experiment-based method to determine stress field and slip lines in metal cutting process. The chip geometry and workpiece's strain and strain rate fields are determined using an in-situ imaging technique. The two-dimensional (2D) heat transfer problem for the steady-state cutting process is solved to derive the cutting temperature, and the flow stresses of work material in the main deformation zone are calculated based on the plasticity theory. Furthermore, the stress field is comprehensively determined to satisfy the stress equilibrium, friction law along the tool-chip interface, and traction-free boundary condition along the uncut chip surface. In addition, slip lines in the main deformation zone are derived according to the direction of maximum shear stress without the assumption of perfect rigid-plastic material. The proposed method is validated by comparing the cutting forces calculated based on the obtained stress field with the experimentally measurements.

Study and Build-Up of Deformation Zone at Cutting of Thin-Walled Tube by Torsion

2017 ◽  
Vol 746 ◽  
pp. 16-21
Author(s):  
S.G. Simagina
Keyword(s):  
Deformation Zone ◽  
Heating Temperature ◽  
Compression Force ◽  
Angular Deflection ◽  
Thin Walled Tube ◽  
Temperature Impact ◽  
Thin Walled ◽  
Force Range ◽  
Intensive Development

Intensive development of Russian aviation and aerospace industries put an emphasis to the problem of quality of using materials and workpieces and to the value of technical and economical indexes in the context of planned production level [1, 2]. Waste-free technologies are preferred. Cutting by torsion or cutting by shear are preferable technologies if thin-walled tube cutting is the main blanking operation. Build-up of workpiece deformation zone plays an important role in the cutting process. Deformation zone determines stability of details during further processing and exploitation. An extended research was conducted about tube separation process using torsion with an active counterpressure. Some parameters was defined in the result of research, in particular: distribution of deformation zone along length and thickness of workpiece, angular deflection and compression force and workpiece heating temperature impact on build-up of whisker disposition in the cut zone. It allows identifying optimum compression force range and temperature conditions. Compliance with recommended practices allows conducting thin-walled tube separation simultaneously with build-up on the workpieces whisker structure that is fortunate for further pressure treatment and exploitation.

A New Stress Mathematical Model of Deformation Zone while Straightening Thin-Walled Tube

2013 ◽  
Vol 652-654 ◽  
pp. 1488-1493
Author(s):  
Zi Qian Zhang ◽  
Yun Hui Yan ◽  
Hui Lin Yang
Keyword(s):  
Mathematical Model ◽  
Theoretical Model ◽  
Plastic Zone ◽  
Deformation Zone ◽  
Shell Theory ◽  
Theoretical Calculations ◽  
Technological Parameters ◽  
Membrane Shell ◽  
Thin Walled Tube ◽  
Thin Walled

As there was no precise theoretical model for predicting the stress of deformation zone while straightening thin-walled tube, some technological parameters depended mostly on the experience of workers and on the results of trials, therefore by means of the membrane shell theory the equilibrium differential equations of stress is obtained firstly, then we analyze the strain of deformation zone, finally lead to a new theoretical model for predicting the stress in the elastic and plastic zone. Subsequently the simulated experiments have been done, the results show that the theoretical calculations coincide well with the simulated results, the errors are within 1％of the calculations, it is testified that the model is correct and efficient for the thin-walled tube straightening.

Development and Enhancement of Thin-Walled Tube Separation Methods

2016 ◽  
Vol 684 ◽  
pp. 218-221 ◽  
Author(s):  
S.G. Simagina
Keyword(s):  
Metal Cutting ◽  
Structural Parameters ◽  
Correct Choice ◽  
Performance Indices ◽  
Metal Separation ◽  
Thin Walled Tube ◽  
Cutting Equipment ◽  
Cut Quality ◽  
Ongoing Development ◽  
Thin Walled

The correct choice of a metal separation method, in particular for thin-walled tubes, is vital for technical and economical performance indices in aircraft building. The most important selection criteria are separation quality, the amount of waste, possibility to consolidate operations and equipment efficiency. These factors require ongoing development & enhancement of tube separation methods. Waste-free technological processes like torsion tube sectioning are preferred. As the result of the extended research of tube separation process using torsion with active counterpressure, particularly the effect of structural parameters on cut quality, optimum tolerance for clearance fit between dies was defined. Compliance with recommended practices during equipment manufacturing will let cut quality reach the value peculiar to the quality value of sectioning method of separation using metal-cutting equipment. Herewith manufacturing becomes waste-free and quarantines calibration of sections adjacent to the cut.

Assessment of Steady-State Metal Cutting Temperature Models Based on Simultaneous Infrared and Thermocouple Data

1991 ◽  
Vol 113 (2) ◽  
pp. 121-128 ◽  
Author(s):  
D. A. Stephenson
Keyword(s):  
Cast Iron ◽  
Steady State ◽  
Inverse Method ◽  
Metal Cutting ◽  
Gray Cast Iron ◽  
Three Dimensional ◽  
Cutting Temperature ◽  
Infrared Measurements ◽  
Thermocouple Method ◽  
Thermocouple Temperature

Several models for metal cutting temperatures which could be applied in simulation programs have been reported in the literature. Since the temperature predicted by the models are difficult to measure, however, there is not sufficient experimental data to determine which available model is most accurate and whether further theoretical refinement is needed. In this paper calculations from four steady-state cutting temperature models are compared with simultaneous infrared and tool-chip thermocouple temperature measurements from end turning tests on 1018 steel, 2024 aluminum, free machining brass, and gray cast iron tubes. Deformation zone temperatures calculated using the models are compared to source temperatures determined from infrared measurements using a new inverse method. Calculated tool-chip contact temperatures are compared to rake face temperatures measured by the widely used tool-work thermocouple method. The data indicates most models, though quantitatively accurate, overestimate cutting temperatures. Models based on Jaeger’s friction slider solution which include workpiece thermal property variations, however, generally give results accurate to within the reliability of experimentai methods for the materials tested. Loewen and Shaw’s model, recently generalized to three-dimensional cutting by Venuvinod and Lau, seems most accurate over a broad range of workpiece and cutting conditions. No model accurately predicts tool-chip temperatures for cast iron or 2024 aluminum, indicating that further theoretical refinement for discontinuous chip formation is needed.

NICROBRAZ 50

Alloy Digest ◽  
1994 ◽  
Vol 43 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Honeycomb Structures ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Low Solubility

Abstract NICROBRAZ 50 is a low-melting, free-flowing filter metal for honeycomb structures and thin-walled tube assemblies. It has low solubility. This datasheet provides information on composition, physical properties, and hardness. It also includes information on corrosion resistance as well as joining. Filing Code: Ni-460. Producer or source: Wall Colmonoy Corporation.

Experiment Study of Oil-Air Lubrication on Cooling of Turning Tools

2011 ◽  
Vol 189-193 ◽  
pp. 3187-3190 ◽  
Author(s):  
Jin Li Wang ◽  
Lin Cai ◽  
Hong Tao Zheng
Keyword(s):  
Metal Cutting ◽  
Research Work ◽  
Cutting Temperature ◽  
Cost Savings ◽  
Machining Process ◽  
Dry Cutting ◽  
Air Lubrication ◽  
Temperature Contrast ◽  
Cooling Technology ◽  
Lubrication Conditions

When lubricants are used according to special requirements, it is possible to achieve considerable cost savings. Compared to conventional coolant cooling technology used in metal cutting, oil-air lubrication increases cooling performance, avoids environmental pollution, reduces running and maintenance costs. The cutting temperature contrast experimental research was based on close to practice 45# steel in dry cutting, wet cutting and oil-air lubrication conditions. The research work concentrated on the superiority of oil-air lubrication cooling and the influence of cutting amount on temperature. The experimental results show that oil-air lubrication is more effective in reducing the cutting temperature than wet cutting or dry cutting, this paper details the cutting temperature curves at several different tests provides a basis for industrial production, improves the level of machining process and the significance was being reported.

scholarly journals Optimal Design of the Shape of a Non-Ball Mandrel for Thin-Walled Tube Small Radius Cold Bending

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1221
Author(s):  
Lu Bai ◽  
Jun Liu ◽  
Ziang Wang ◽  
Shuanggui Zou
Keyword(s):  
Ideal Point ◽  
Small Radius ◽  
Grey Wolf Optimizer ◽  
Forming Quality ◽  
Hollow Section ◽  
Cold Bending ◽  
Bending Process ◽  
Before And After ◽  
Thin Walled Tube ◽  
Thin Walled

In the field of cold bending, it is necessary to use ball mandrels, especially to bend thin-walled tubes with a small radius. However, the bending process with a ball mandrel is complex and expensive, and it is easy to jam the core ball inside the tube. To solve these issues, we designed two kinds of hollow non-ball mandrel schemes with low stiffness that were suitable for the small radius bending of thin-walled tubes. We evaluated the forming quality of cold bending numerically and the influence of the hollow section length and thickness on the forming indices. Our results showed that the thickness of the hollow section has a greater influence on forming quality than the length. As the hollow section’s thickness increased, the wrinkling rate first declined by approximately 40% and then increased by above 50%. When the thickness was 11 mm in scheme 1 and 13 mm in scheme 2, the wrinkling rate reached minimum values of 1.32% and 1.50%, respectively. As the hollow section’s thickness increased, the flattening rate decreased by more than 60% and the thinning rate increased by about 40%. A multi-objective optimization of forming indices was carried out by ideal point method and grey wolf optimizer. By comparing the forming results before and after optimization, the feasibility of using the proposed hollow mandrel was proved, and the hollow mandrel scheme of standard cylinder is therefore recommended.

scholarly journals Cold Forging Effect on the Microstructure of Motorbike Shock Absorbers Fabricated by Tube Forming in a Closed Die

2021 ◽  
Vol 11 (5) ◽  
pp. 2142
Author(s):  
Trung-Kien Le ◽  
Tuan-Anh Bui
Keyword(s):  
Material Flow ◽  
Cold Forging ◽  
Technological Parameters ◽  
Forming Process ◽  
Tube Forming ◽  
Shock Absorbers ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Quality Of Products ◽  
Forming Defects

Motorbike shock absorbers made with a closed die employ a tube-forming process that is more sensitive than that of a solid billet, because the tube is usually too thin-walled to conserve material. During tube forming, defects such as folding and cracking occur due to unstable tube forming and abnormal material flow. It is therefore essential to understand the relationship between the appearance of defects and the number of forming steps to optimize technological parameters. Based on both finite element method (FEM) simulations and microstructural observations, we demonstrate the important role of the number and methodology of the forming steps on the material flow, defects, and metal fiber anisotropy of motorbike shock absorbers formed from a thin-walled tube. We find limits of the thickness and height ratios of the tube that must be held in order to avoid defects. Our study provides an important guide to workpiece and processing design that can improve the forming quality of products using tube forming.

A top-down approach making cellulose carbonaceous aerogel/MnO2 ultrathick bulk electrodes with high mass loading for supercapacitors

2021 ◽  
Author(s):  
Weiye Zhang ◽  
Yanchen Li ◽  
Beibei Wang ◽  
Jingmeng Sun ◽  
Lin Lin ◽  
...  
Keyword(s):  
Porous Carbon ◽  
High Mass ◽  
Mass Loading ◽  
Top Down ◽  
Thin Walled Tube ◽  
Natural Wood ◽  
Thin Walled ◽  
Array Structure

A cellulose carbonaceous aerogel/MnO2 ultrathick electrode with a unique low curvature, porous carbon thin-walled tube array structure was obtained from natural wood using a simple top-down approach.

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