Study on the Process of Pure Shearing and Fracture for AISI-1020 and AISI-1045 Blanking with Negative Clearance

2010 ◽  
Vol 135 ◽  
pp. 215-219
Author(s):  
Wei Fu Fan ◽  
Jian Hua Li ◽  
Zhong Mei Zhang
Keyword(s):  
Experimental Data ◽  
Electron Microscope ◽  
Research Result ◽  
Reference Value ◽  
Work Piece ◽  
Fine Blanking ◽  
Aisi 1045 ◽  
Negative Clearance ◽  
Metallic Sheet ◽  
Scanning Electron

This paper carried through fine-blanking with negative clearance processing experiment with the AISI-1020 and AISI-1045 and obtained the work piece of fine blanking with negative clearance. The fractography photographs in the different deform regions of rollover zone, shearing band, fracture zone and under sheared surface were scanned by scanning electron microscope (SEM-JSM-6360LV). The research result indicates that the plastic flow of fine-blanking with negative clearance has been carried out to punch downspin, then jib at the place of allowance value, so that the length of work piece burnish band as much as possible to maximize and the length of the smooth shearing fracture could reach more than 90% thickness of the metallic sheet. Owing to the ejector negative direction blanking, the second burnish band could be formed in the process of ejecting and the work piece has no burr in the undermost sheared face. The place of fracture of fine-blanking with negative clearance has emerged into the middle of work piece, not into the sheared undermost. And the width of fracture band is very tiny, only 50-100 micron. The research result provides theoretic reference and the experimental data for the practice application. It has instructive significance and reference value to manufacturing application.

Study on the Optimized Blanking Allowance of Fine-Blanking with Negative Clearance for AISI-1020 and AISI-1045

2010 ◽  
Vol 135 ◽  
pp. 179-183
Author(s):  
Jian Hua Li ◽  
Wei Fu Fan ◽  
Zhong Mei Zhang
Keyword(s):  
Research Result ◽  
Reference Value ◽  
Work Piece ◽  
Key Factors ◽  
Fine Blanking ◽  
Force Increase ◽  
Aisi 1045 ◽  
Negative Clearance ◽  
Deform 2D

The fine-blanking procedure for AISI-1045 and AISI-1020 under the condition of various blanking allowance has been simulated by the DEFORM-2D software, and a large number of fine-blanking experiments have been made. Some key factors, like blanking allowance affecting upon the ejector force, the perfect ratio of fracture and the fracture procedure, are discussed, and the principles for choosing value of blanking allowance are given. In order to reduce ejector force, increase the perfect ratio of fracture and separate scrap from sheet metal easily, a smaller value C of blanking allowance should be adopted whenever possible. The value C of blanking allowance should be chosen according to the mechanism capability. For some types of steels which have good plasticity, a larger value C of blanking allowance should be chosen, so that the work-piece without blanking edge could be obtained. For some types of steels which have poor plasticity, a smaller value C of blanking allowance should be chosen to obtain blanking work-piece with higher quality. Generally speaking, the optimized value of blanking allowance should be from 0.15mm to 0.35mm, and the largest value must be less than 0.5mm.The research result has instructive significance and reference value to improve the quality of work pieces and the perfect ratio of sheared band.

Qualitative Analysis and Study the Workpiece Shearing Surface Quality of Fine-Blanking with Negative Clearance

2011 ◽  
Vol 697-698 ◽  
pp. 371-376
Author(s):  
Hong Du ◽  
Zhong Mei Zhang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Qualitative Analysis ◽  
Surface Quality ◽  
Reference Value ◽  
Quality Standard ◽  
Fine Blanking ◽  
Negative Clearance ◽  
Scanning Electron

The workpieces of fine blanking with negative clearance were obtained through the fine-blanking with negative clearance processing experiment. The fractography photographs of workpieces shearing surface were scanned by scanning electron microscope (SEM), and the characterization parameters and quality standard of workpieces shearing surface with negative clearance were analyzed in the processing of blanking. According to the characterization parameters and quality standard of workpieces shearing surface with negative clearance, the workpiece with the length ratio of burnish band, deflection error, rollover error and blanking burr were analyzed qualitative. The findings have a certain reference value to the blanking related profession.

Study on the Impact of Fine-Blanking with Negative Clearance on the Materials Microstructure and Hardness

2010 ◽  
Vol 97-101 ◽  
pp. 149-152
Author(s):  
W.F. Fan ◽  
J.H. Li ◽  
Zhong Mei Zhang
Keyword(s):  
Plastic Deformation ◽  
Research Result ◽  
Original Material ◽  
Fine Blanking ◽  
Complicated Process ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Negative Clearance ◽  
The Impact ◽  
1045 Steel

The Fine-blanking with negative clearance processing is very complicated process because the blanking clearance is negative clearance, for this reason, the state of stress and strain in sheet inside are also more complicated than conventional blanking. In the process of fine-blanking with negative, plastic deformation of the material is fiercer than conventional blanking, and the change of material inner structure and hardness is more intense because of plastic deformation. The deformation principle of fine-blanking deformation with negative clearance is analyzed by means of streamline and metallographic photograph and micro hardness. The impact of fine-blanking with negative clearance on the materials microstructure and hardness is discussed. The research result indicates that the hardening value is 1.8 times than original material itself and the maximum harden depth is 2.2mm for AISI-1045 steel in the process of blanking with negative clearance. Therefore, it could enhance fatigue strength and the working life of workpiece greatly because of the improvement of the material inner structure.

Study on Microstructure Character in the Deformable Regions of AISI-1045 Steel Fine Blanking with Negative Clearance

2009 ◽  
Vol 628-629 ◽  
pp. 541-546 ◽  
Author(s):  
J.H. Li ◽  
Wei Fu Fan ◽  
Zhong Mei Zhang
Keyword(s):  
Work Piece ◽  
Micro Hardness ◽  
Fine Blanking ◽  
Metallic Crystal ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Metal Deformation ◽  
Negative Clearance ◽  
1045 Steel ◽  
The Relationship

This paper obtained work piece of fine blanking with negative clearance by experiment. The microstructure and fractography photograph in regions like rollover zone, shearing band, under sheared surface and fracture band were scanned by instrument of scanning electron microscope (SEM-JSM-6360LV). The fine-blanking with negative clearance makes the metal deformation regions into a state of triaxial stress precise and it causes an intense metallic stream that brings about inter-dislocation and distortion of metallic crystal product under the action of stronger force, so the metallic crystal is reset and the isometric metallic crystal of shearing zone is staved, sloped and pulled and it appears as dense lined and strip crystal. The paper analyzes the full course of producing and development of micro crack in the ejecting stage in the fine-blanking processing of negative clearance. And the course of final rupture is also analyzed. The relationship curve of blanking stroke and micro hardness is measured by Vickers Hardness instrument (MH-6). The deforming principle of fine blanking deformation with negative clearance is analyzed by means of microstructure, metallographic photograph and micro hardness.

The Contrast Research of the Finite Element Simulation for Ordinary and Fine Blanking with Negative Clearance

2008 ◽  
Vol 575-578 ◽  
pp. 316-321 ◽  
Author(s):  
H. Du ◽  
S.M. Ding
Keyword(s):  
Experimental Data ◽  
Reference Value ◽  
Engineering Practice ◽  
Fine Blanking ◽  
Equipment Investment ◽  
Element Simulation ◽  
Negative Clearance ◽  
Material Energy ◽  
Blanking Process

This paper puts forward a negative clearance fine-blanking theory and its technique process, and introduces the technical processing of fine-blanking which can be used on ordinary punching machines. In this paper, computer simulation and the experimental study of negative clearance fine-blanking process are carried out. Thus the parameters of the force of blanking, the value of negative clearance are determined. The effect of fine-blanking quality was obtained, and the perfect rate of the blanking fracture achieves 90%. By comparing negative clearance precise blanking with conventional blanking, the following conclusions are drawn: 1. Blanking quality of negative clearance blanking is increased by 57% than that of conventional blanking. 2. The down surface of the work-pieces obtained by the conventional blanking processing have 0.2 - 0.5 mm longitudinal burrs, while the work-pieces obtained by the negative clearance blanking have no burrs. Thus the processing of clear away the burrs could be spared. And the manpower, the material, energy and the equipment investment are saved. The researching result provides theoretic reference and the experimental data for the engineering practice. It has instructive significance and reference value to engineering manufacturing.

Study and Analysis the Facture Mechanism for Fine-Blanking with Negative Clearance on 60Mn

2012 ◽  
Vol 229-231 ◽  
pp. 91-94
Author(s):  
Z.M. Zhang ◽  
F. Li ◽  
H. Zhang
Keyword(s):  
Work Hardening ◽  
Extrusion Process ◽  
Work Piece ◽  
Fine Blanking ◽  
The Common ◽  
Clearance Process ◽  
Punching Process ◽  
Negative Clearance ◽  
Extrusion Forming ◽  
Scanning Electron

In order to improve the punching process, further enhance the blanking section quality. This paper studied the common blanking of 60Mn and the fine blanking with negative clearance of 60Mn blanking work piece metallographic structure by using scanning electron microscope. The results show that the fine blanking with negative clearance process can increase the work-hardening degree and further thin the punching surface tissue, inhibit the crack, and make the blanking surface smooth. The tensile and tear result in the generation of cracks and burrs, and the extrusion forming of fine blanking with negative clearance inhibit the generation of cracks, and eliminate the conditions of the burrs. As the extrusion process, the degree of work hardening in fine blanking with negative clearance is higher than the common blanking, the organizations are more closed.

Comparative Study of the Process Fracture between Fine-Blanking with Negative Clearance and Conventional Blanking

2010 ◽  
Vol 97-101 ◽  
pp. 191-194 ◽  
Author(s):  
Hong Du ◽  
Wei Fu Fan ◽  
Zhong Mei Zhang
Keyword(s):  
Smooth Surface ◽  
Work Piece ◽  
Separation Mechanism ◽  
Final Phase ◽  
Fine Blanking ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Negative Clearance ◽  
1045 Steel ◽  
Blanking Process

The different separation mechanism of fine-blanking with negative clearance and conventional blanking under different blanking process are analyzed through fine-blanking with negative clearance and conventional blanking processing experiments on AISI-1045 steel. The fractography photographs in the different deformation regions, such as rollover zone, shearing band, fracture zone and burr zone are scanned by scanning electron microscope (SEM-JSM-6360LV). The place of fracture of fine-blanking with negative clearance has emerged into the middle of work piece not the undermost of workpiece, and the width of fracture band is as tiny as 50-100 micron. The smooth surface formed by the uniform plastic flow in the process fine-blanking with negative clearance, and the full course of finally toughness fracture have been analyzed in the final phase of ejecting in fine-blanking with negative clearance. From the perspective of material meso-damage, the fracture mechanism of special blanking process with negative clearance has been illustrated in details.

Study on Working Hardening for AISI-1020 and AISI-1045 Steel Fine-Blanking with Negative Clearance

2010 ◽  
Vol 431-432 ◽  
pp. 405-408 ◽  
Author(s):  
J.H. Li ◽  
Wei Fu Fan ◽  
Zhong Mei Zhang
Keyword(s):  
Work Hardening ◽  
Working Life ◽  
Work Piece ◽  
Micro Hardness ◽  
Fine Blanking ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Negative Clearance ◽  
1045 Steel ◽  
Vickers Micro Hardness

This paper carries through pure shearing fine-blanking processing experiment with negative clearance for the AISI-1020、AISI-1045 steel and the relations curves of the blanking force and the blanking stroke is obtained. The micro hardness of the sheared surface for the blanked work pieces in breadthways and lengthways direction is measured by Vickers-micro hardness instrument (MH-6), thereby the relations curves of punch stroke and the micro-hardness of the blanking work pieces are gained. The relation between work hardening degree and blanking clearance for the negative blanking is obtained too. This paper focuses on formation mechanism of work hardening for the negative blanking and analyzes the work hardening capability of blanked work piece. The work hardening degree is compared to the materials which possess different hardening index. The research shows that the work hardening degree of the blanking work pieces is strengthened evidently by the fine-blanking with negative clearance and the hardening layer of blanking fracture could enhance structure intensity and wear resistance of blanking work piece evidently. Therefore, it could enhance fatigue strength exceedingly and extend the working life of work piece greatly.

Study on Work Hardening Performance of Pure Shearing Fine-Blanking with Negative Clearance for ASTM-Gr.D and ASTM-1022 Steel

2010 ◽  
Vol 97-101 ◽  
pp. 145-148
Author(s):  
J.H. Li ◽  
W.F. Fan ◽  
Zhong Mei Zhang
Keyword(s):  
Work Hardening ◽  
Work Piece ◽  
Micro Hardness ◽  
Fine Blanking ◽  
Negative Clearance ◽  
Distribution Of Stress ◽  
Improve Fatigue Strength ◽  
Important Significance ◽  
Improve Fatigue

In the process of blanking, the work hardening capability of material possesses very important significance. It not only affects the internal stress value of distorting material, the distribution of stress and the value of blanking force, but also blanking deforming limit and quality of blanked work piece. This paper carries through pure shearing fine-blanking processing experiment with negative clearance for the ASTM-Gr.D and ASTM-1022 steel as well as the micro hardness of the sheared surface for the blanked work pieces in breadthways and lengthways direction measured by Vickers-micro hardness instrument (MH-6). Mechanism of work hardening for fine-blanking with negative clearance is discussed. Meanwhile, the work hardening capability of blanked work piece is analyzed. The work hardening degree of the materials possessing different hardening index is compared. It could be concluded that the work hardening degree of the blanking work pieces was strengthened evidently by the fine-blanking with negative clearance. The hardening layer of blanking fracture could enhance structure intensity and wear resistance of blanking work piece evidently. Therefore, it could improve fatigue strength and the working life of work piece greatly.

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