Direct metal part forming of 316L stainless steel powder by electron beam selective melting

Abstract

Electron beam selective melting (EBSM) is a new type of rapid manufacturing of direct metal fabrication technology, which combines electron beam machining with rapid prototyping. It makes use of some advantages of an electron beam, such as high energy density, high absorption rate, and vacuum environment. In this study, direct metal part forming of gas and water-atomized 316L stainless steel powder were researched in detail. The one-dimensional experiments showed that the gas-atomized 316L stainless steel powder could be formed in a solid line at slow scanning velocity and low beam current while the water-atomized powder had serious balling and break-up phenomena at most conditions. The powder mixture containing 40–60 wt % of the gas-atomized powder has the optimum forming ability. The forming technology of the mixture powder must be divided into three steps: placing step, heating step, and melting step. After research on the technology parameters, some two-dimensional facets and three-dimensional parts were produced by EBSM. The microstructure of the three-dimensional forming parts was fine; the interfaces between the layers were metallurgically bonded.

Keywords

electron beam selective melting rapid manufacturing direct metal part forming 316L stainless steel powder

References

Wohlers

Rapid prototyping, tooling and manufacturing state of the industry. Annual worldwide progress report, Wohlers Associates, Inc., Fort Collins, Colorado, 2004.

Cormier

Harrysson

West

Characterization of H13 steel produced via electron beam melting. Rapid Prototyping J., 2004, 10(1), 35–41.

Yan

Development of electron beam selective melting forming system (in Chinese) 2005 (Tsing Hua University, Beijing).

Matz

J. E.

Carbide formation in a nickel-based super alloy during electron beam solid freeform fabrication, 1999 (MIT Press, Cambridge, Massachusetts).

Taminger

K. M. B.

Hafley

R. A.

Characterization of 2219 aluminum produced by electron beam freeform fabrication. In Proceedings of the 13th Solid Freeform Fabrication Symposium (Eds. Bourell

D. L.

Crawford

R. H.

Beaman

J. J.

Wood

K. L.

Marcus

H. L.

), University of Texas at Austin, Austin, Texas, USA, August 2002, pp. 482–489.

Maeda

Childs

T. H. C.

Laser sintering (SLS) of hard metal powders abrasion resistant coatings. J. Mater. Processing Technol., 2004, 149, 609–615.

Zeng

Yan

Ren

Yang

Particle technology of mineral processing (in Chinese), 2001, pp. 127–130 (China University of Mining and Technology, Xuzhou).

Wang

Gao

Vacuum electron beam welding equipment and technology (in Chinese), 1990, pp. 74–82 (Atom Energy Press, Beijing).

Yan

Lin

, Situation analyzing of metal powder in electron beam direct melting technology. J. Tsing Hua Univ. (Sci. Technol.), 2005, 8(45), 1012–1015.

10.

Introduction to powder technology (in Chinese), 1993, pp. 31–58 (Tongji University Press, Shanghai).

11.

Suman

On some physical aspects of process control in direct selective laser sintering of metals — Part I. In Proceedings of the 12th Solid Freeform Fabrication Symposium (Eds Bourell

D. L.

Beaman

J. J.

Crawford

R. H.

Marcus

H. L.

Wood

K. L.

Barlow

J. W.

), University of Texas at Austin, Austin, Texas, USA, 2001, Vol. 8, pp. 102–109.

12.

Keicher

D. M.

Smugeresky

J. E.

Romero

J. A.

, Using the laser engineered net shaping (LENS) process to produce complex components from a CAD solid model. Proc. SPIE, 1997, 2293, 91–97.

13.

Gao

Methods of orthogonal design and linear regression (in Chinese), 1988, pp. 17–70 (Metallurgy Industry Press, Beijing).