The process of strand casting followed by forge rolling has been under continuing development by Roblin Steel Company since 1964. As reported by W. Wojcik, Roblin Steel made a comparison of their product with the best that traditional processing could offer, i. e. , bars produced by rolling of fully killed steel ingots. In bringing out the de- sirable characteristics of strand-cast, forge-rolled bars for use as starting material in forging, Dr. Wojcik indicated that there is no measurable difference in mechanical properties between strand-cast/forge-rolled and conventionally rolled materials. Additional work is in progress to characterize fully the new product. Roblin’s process consists of casting a continuous strand at as low a pour temperature as possible (typically 35 °C above the liquidus) after silicon killing and aluminum deoxidizing. The continuous-cast strand is then forge-rolled between four rolls, 90 deg apart, with only the minimum amount of mechanical working necessary to se- cure mechanical properties.
The final presentation of the conference was by W.H. Altergott of IIT Research Institute, on the principles and recent applications of the squeeze casting process. Squeeze casting is a means of making closed-die forgings using a liquid metal charge in place of a solid preform. The use of liquid metal overcomes several traditional problems inher- ent in forging, including limited shape detail, internal and surface cracking due to inadequate ductility or forgeability of the workpiece material, and high cost. In comparison with permanent mold casting or die casting, squeeze casting produces a much liner, denser internal structure, as well as improved surface finish, due to the high level of applied pressure (10,0tJfl to 30,000 psi). Mechanical properties are invariably superior to conventional cast properties, and gen- erally tend to fall in between the longitudinal (high) and
J. APPLIED METALWORKING
long-transverse (low) properties of wrought products. According to Mr. Altergott, IIT Research Institute has been developing squeeze casting since 1969. The process starts
Session I: Optimum Material Utilization (Chairman: R.P. O’Shea, International Harvester Company, Hinsdale, IL) Close Tolerance Spindle Forging (J. Sniezek* and P.C.
Theis, Rockwell International, Morristown, TN)
with ladling a fixed amount of molten metal into a pre- Near-Net Forging of Drive Train Components (A.M.
heated, lubricated die in a hydraulic press. The press ram is then brought down, forcing a punch into the die cavity to extrude liquid metal with relative ease to fill the die. Pressure is maintained until the part is completely solidified, after which the ram is retracted and the part ejected out of the die. This technique has been used successfully in several aerospace, ordnance, and automotive applications, reported Mr. Altergott, including one commercial item — an alumi- num automotive wheel squeeze-cast by Toyota (Japan). Besides aluminum alloys, other materials evaluated by IIT
Sabroff,* Eaton Corporation, Willoughby Hills, OH) Sinta-Forge, an Efficient Production Process for lI'igh Fa-
tigue Stress Components (R.M. Szary,* Federal Mogul Corporation, Romulus, MI)
Cold Rolled Components for Gas Turbine Engines (W. Hansen * and N . T. Huuskonen , General Electric Company — Aircraft Engine Group, Lynn, MA)
Session II: Optimum Machine Utilization (Chairman: R. Douglas, Eaton Corporation, Willoughby Hills, OH) Automated Forging of Large Crankshafts (J.L. Knott* and 锻造技术英文文献和中文翻译(10):http://www.youerw.com/fanyi/lunwen_79386.html