Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


osu1332117974.pdf (11.26 MB)

ETD Abstract Container

Abstract Header

Investigation of Lubrication and Springback in Forming of Draw Quality and Advanced High Strength Steels

Kardes Sever, Nimet
http://rave.ohiolink.edu/etdc/view?acc_num=osu1332117974

Abstract Details

2012, Doctor of Philosophy, Ohio State University, Industrial and Systems Engineering.
A good quality part is a part without any defects (no fracture or wrinkle), with good surface finish and with desired dimensions. Manufacturing a good quality part is the ultimate goal of the sheet metal forming industry. This goal can be achieved by many different ways depending on the problem in the sheet metal forming process. If the problem is fracture, bad surface finish or galling, the problem can be solved by reducing the friction between the tool and the workpiece. Friction is affected by contact pressure, temperature, sliding distance, sliding velocity, die material/coating, sheet coating, surface roughness of die and sheet, the lubrication. In the present study, only the effects of lubrication and sheet coating were investigated. Various lubricants such as petroleum-based and water-based lubricants, which were newly developed for conventional steels, were evaluated in terms of chemical stability, corrosion, cleanability and drawability. Production type tests such as strip and cup drawing tests were utilized to evaluate the drawability performance of the selected lubricants. It was found that water-based lubricants performed better than the petroleum-based lubricants in deep drawing of conventional steels. Several galvanized coatings that were also developed for conventional steels were evaluated in terms of anti-galling performance by conducting strip drawing and strip ironing tests in the study. In addition, micrographs, roughness and hardness measurements were done. It was concluded that the surface characteristics of the die and sheet affected the anti-galling performance of galvanized coatings. If the problem is inaccurate dimensions due to the elastic recovery of the part after the load is removed, springback needs to be investigated. Springback can be predicted by utilizing finite element analysis (FEM) and the part can be formed to desired dimensions. The accuracy of springback predictions with FEM depends on the material properties such flow stress and E-modulus. The deformation is usually biaxial in stamping. Thus, flow stress should be obtained under biaxial conditions (either by bulge or dome tests). In addition, E-modulus is assumed to be constant during deformation. However, E-modulus decreases with strain in advanced high strength steels (AHSS). In this study, the aim is to improve the accuracy of the springback predictions for AHSS by considering variable E-modulus in FEM. Different bending tests such air bending, U-bending, U-flanging and S-shape forming tests were performed. It was determined that the effect of variable E-modulus on springback predictions changes with the magnitude and the type of deformation.
Taylan Altan (Advisor)
Jerald Brevick (Committee Member)
Gary Kinzel (Committee Member)
326 p.
Mechanical Engineering
Stamping; Lubrication; Galling; Springback; Flow Stress; Draw Quality Steels; Advanced High Strength Steels

Recommended Citations

Citations

  • Kardes Sever, N. (2012). Investigation of Lubrication and Springback in Forming of Draw Quality and Advanced High Strength Steels [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1332117974

    APA Style (7th edition)

  • Kardes Sever, Nimet. Investigation of Lubrication and Springback in Forming of Draw Quality and Advanced High Strength Steels. 2012. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1332117974.

    MLA Style (8th edition)

  • Kardes Sever, Nimet. "Investigation of Lubrication and Springback in Forming of Draw Quality and Advanced High Strength Steels." Doctoral dissertation, Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1332117974

    Chicago Manual of Style (17th edition)

osu1332117974
1,476
© 2012, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.