August 2025 Volume 7

FORGING RESEARCH

Figure 2: Colorado School of Mines student Isaak Keskula adding a helical twist to the handle of a steel bottle opener that he hammered in the forge shop. After the hands-on experience, the students have to learn and apply metal forming theory and metallurgy. For example, the students compute the relative amounts of energy that go into deformation due to their hammer strikes versus the thermal energy imparted by reheating. For the graduate-level course, students also examine the microstructures they have imparted through their labors, as shown in the side-by-side optical micrographs of the handle of a bottle opener in Figure 3. The students can observe that the modest amount of deformation from twisting in the bottle opener handle results in a nearly equiaxed alpha iron grain structure. The air cooling after the final reheat results in sparse colonies of pearlite forming at grain boundaries. The critical importance of metallurgical processes is anchored as students recognize that they created these microstructures with their own hands.

Figure 4: Full-field thermal imaging teaches students how frictional heating contributes to the temperature distribution during upsetting of a cylindrical aluminum workpiece using a hydraulic press. Likewise, conducting classic ring compression tests allows the students to directly experience the advantages and disadvantages of different classes of lubricants. Wyatt Biggs and Grace Cantrell (Forging Industry Women’s Scholarship winner) are measuring the inner and outer diameters of rings before comparing various lubricants to determine how lubricity affects the coefficients of friction during compression. Students learn that successful metal forging isn’t just about the metals. The surface condition of the dies, the choices of lubricants, the methods of applying lubricants, and the speed of operations are equally important.

Figure 3: Micrographs of inside the handle of the 1018 steel bottle opener after hammer forging show nearly equiaxed alpha-phase grains with colonies of pearlite (the dark regions) that formed at grain boundaries. The left image is a 1200x optical micrograph after etching with ferric and copper chlorides, while the right image better highlights grain boundaries by applying differential interference contrast. Both photos were prepared by Forging & Forming course student CJ Hawkins. Meanwhile, in class, students learn the mechanics of forging alloys and the important role of friction and lubricants. They also delve deeply into the metallurgy and microstructure evolution induced in ferrous and non-ferrous alloys. Every other week, they extend their learning with hands-on open-die and closed-die forging. For example, in open-die upsetting of aluminum, students experience firsthand the effects of different aspect ratios of cylindrical workpieces on metal flow and temperature transients. Figure 4 shows a student observing the frictional heating of the top and bottom surfaces of the aluminum workpiece during an upsetting operation between unlubricated flat dies. Later in the courses, the students use finite element methods to simulate forging strains and temperature distributions; but there is no substitute for seeing the effects in the forge shop.

Figure 5: Grace Cantrell (a Forging Industry Women's Scholarship winner) and Wyatt Biggs measuring inner and outer diameters of aluminum rings compressed between flat platens with various lubricants.

FIA MAGAZINE | AUGUST 2025 65