Possibility of the Increase in Titanium Sheets' Drawability

Abstract

Forming of titanium sheets, especially titanium alloy sheets, is very difficult due to low drawability caused by a high ratio of the yield point to the tensile strength Re/Rm, usually more than 90%. Although drawability of titanium sheets can be enhanced by forming at elevated temperatures it is avoided due to the high costs and difficulties associated with the operation of the process. Therefore the authors have developed an unconventional stamping method allowing for forming of almost unworkable materials at ambient temperature, such as Ti6Al4V titanium alloy. The paper presents both numerical simulation and experimental results of the stamping process using a device specially designed for this purpose.

Forming Of Spherical Titanium Cups From Circular Blanks With Cutouts On The Perimeter

“…It should be remembered that forming titanium alloys at increased temperature necessitates solving the problems of its tendency for reacting with oxygen, nitrogen and hydrogen. Absorption of these gases causes unfavourable structural changes and, consequently, deterioration of strength parameters [5,[8][9][10][11][12]. The studies [13][14][15] showed that obtaining greater forming depth is also possible during forming of tailor-welded blanks (TWBs).…”

“…Publications in this field focus primarily on mechanical properties, capability of plastic strain, including methods of determination of forming limit diagrams (FLD) with regards for the effect of anisotropy of mechanical properties, strain rate and temperature as well as opportunities for application of modern methods of forming and optimization of parameters of these processes [1,2,[17][18][19][20][21][22]. Authors of the studies [10] point to a very low, almost zero drawability of sheet metal made of titanium Gr 5 at the temperature of environment.…”

“…Due to very low capability of plastic strain at the ambient temperature and strong spring-back effect compared to conventional deep drawing steel sheets, obtaining of products made of titanium sheet metal (Gr 5) using conventional methods is limited and requires expert knowledge and non-standardized approach to solving this problem [5][6][7]. Obtaining deep drawn parts with complex geometry from hard-deformed sheet metal requires modification of conventional methods of forming or application of modern technologies such as electromagnetic forming, explosive forming, impulse forming, hydroforming or incremental sheet forming [1][2][3][4][7][8][9][10][11]. It should be remembered that forming titanium alloys at increased temperature necessitates solving the problems of its tendency for reacting with oxygen, nitrogen and hydrogen.…”

The Effects Of Friction On Stamping Process Of Sheet Metals Used In Aviation

“…Among the various production techniques, only sheet-metal forming enable the production of thin-walled components with high strength [1][2][3][4]. According to [5,6], the tribological properties of the deformed materials and the friction conditions are important factors determining the results of sheet metal forming, particularly in the deep drawing process.…”

Experimental And Theoretical Determination Of Forming Limit Curve

“…Strain -hardening exponent n, normal anisotropy ratio r and the ratio of yield strength to tensile strength R e /R m are the most essential parameters describing sheet formability [5][6][7][8][9][10][11]. Formability is defined as the sheet -metal ability to be formed into a specific shape without failure.…”