Titanium alloys cylindrical components unevenness during pneumo-thermal forming

Аuthors

Kovalevich M. V.^1*, Goncharov A. V.^2**, Gukov R. Y.^2***

1. ,
2. Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

*e-mail: kovalevich_mv@mail.ru
**e-mail: goncharov_alexei@mail.ru
***e-mail: lin0ge@yandex.ru

Abstract

The main goal of the paper is determination the dependency of maximum thinning of the material from geometrical parameters during pneumo-thermal forming (superplastic forming — SPF) of various standard forms.

This paper describes the data, obtained by studying the cylindrical shape components formation.

To solve this problem, mathematical simulation of cylinders of various configurations of alloy VT20 was made with PAM STAMP 2G software package.

The simulation was performed for the groups of cylinders with radius of R = 50 mm and thickness of S = 1 mm, and with radius of R =80 mm and thickness of S = 2 mm. The results of the simulation are presented by S’R’ diagram for various H’ values.

The lines were constructed using linear approximation, and coefficients “a” and “b” were obtained for approximate lines. Also graphs a(H’) and b(H’) were constructed.

Substituting the obtained values of coefficients a(H’) and b(H’) in the of the line equation, approximate expression was obtained for estimating minimum wall thickness for AMg6M alloy cylinders with R = 50 mm, R = 80 mm and cylinders with R = 80 mm from.

As it is seen from the dependencies, these coefficients are approximately equal, which allows us to extend this dependency to other group of cylinders.

The dependencies were tested with AMg6M alloy.

Component thickness was measured by ICH-10 indicator. The experimental and simulation results revealed good convergence.

After the cylinder simulation results analysis, recommending cylinder forming selection graph, depending on the required thinning [S/S0] Ч 100% was developed. This graph presents the recommendation for designers and technologists. Its main purpose is to simplify the design of components with optimal mass characteristics. The knowledge to what relative parameters area a component belongs would sate the design time.

Thus, the following ratios for cylindrical components are considered optimal:

1. For zones with thinning greater than 78%, better apply molding or drawing.

2. For zones with thinning of 45-78% (0,1 < H’ < 0,75 и 0,05 < R’< 0,7) the best optimal solution SPF technology implementation.

3. For zones with thinning of 25-45% the better solution is to use pre-stretch for set of material from flange zone with following pneumatic forming. For zones with thinning of 16-25% (for components with H’ > 0,8 and R’ < 0,5) SPF technology implementation is not advisable.

Keywords:

sheet-metal forming, pneumo-thermal forming, thinning

References

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