Fig. 14.4. Molybdenum backextrusion tooling with starting blank and as-extruded product.
we often had more than temperature as a variable and were unable to conclude what might be the optimum temperature. However, we did find we were able to consistently produce good quality back extrusions at temperatures from 1600 to 1700째C. Tensile and bendtest specimens have been machined from back extrusions made at several temperatures for mechanical properties evaluation. 14.3 WELDING MOLYBDENUM
A. J. Moorhead Three major types of welded joint (tube-to-header, header-to-header, and tube-to-tube) are required for fabrication of the molybdenum test stand for chemical processing. Our initial work on these three joints was
described in an earlier report." During this period we have fabricated more complex structures which simulate actual loop components. We are also optimizing our welding procedures and are designing and building weld fixtures. As an aid to fabrication, we have begun constructing a full-scale mockup of the molybdenum test stand. Wooden models of the four pots were made, and short stubs of Monel tubing were inserted in the.appropriate holes in the bosses. The tubes were previously bent to the shapes required of the molybdenum tubes. These
4. A. Moorhead and T. Housley, MsR program Semiannu. bop. Rep. F& 28, 1971, 0 ~ ~ ~ 4 6 7pp.6 , 220-21.