Magnesium Wrought and Fabricated Products Yesterday, Today, and Tomorrow

The developers of magnesium metal production were always interested in methods of producing alloys and products. Casting was the first major development in the production of structural parts, but rolling, forging and extrusion closely followed it. This paper reviews the tremendous historical developments in wrought products during the 1930’s and 1940’s. At the peak of magnesium production for World War II, thousands of tons of magnesium sheet were produced each month and fabricated into aircraft parts. Several aircraft were made of all magnesium extrusions, sheet and castings. These included the German Arado 196 and the US XP56 and F-80. Many other aircraft used large quantities of rolled magnesium. Most of the magnesium was produced on rolling mills developed for other metals until Dow built the large magnesium fabrication mill at Madison, Illinois (Owned and operated today by Spectrulite Consortium). Brooks and Perkins also fabricated magnesium parts and built a rolling mill in 1952. Explanation of Subject Development The purpose of this paper is not to explore the metallurgical details of the effects of the various wrought processes that can be applied to magnesium. It can be seen by doing a very cursory review of the magnesium processes that some of the apparent disadvantages can be turned into advantages if properly understood and exploited. Things like the marked capacity of magnesium for preferred orientation can be exploited in certain forged pieces. The paper will review the past and some developments of wrought products for information purposes. Introduction Magnesium metal has been used in a number of structural applications for many years. The vast majority of those applications have been as castings. After magnesium was put into commercial production, the main uses were pyrotechnic. It was not until Dr. Pistor and German researchers developed melting fluxes that magnesium parts could be made that would withstand exposure to corrosive atmospheres. Castings were the main focus of attention by the main producers of magnesium in both the US and Germany. It was after 1930 before much work was done with rolling and forging and extrusions of magnesium. The work of the Italians in Northern Italy was the first substantial effort to use the light magnesium parts (with castings) in aircraft. The Germans watched, visited and learned rapidly. As the German government was reorganized in 1933, industry took steps to develop magnesium. Immediately steps were taken to design and produce parts that were incorporated into the construction of vehicles, airplanes and rockets. With the start of defense plant activities in the US, many companies installed magnesium wrought product operations. This was with direct government support, first from the Defense Plant Corporation, and later from the Wartime mobilization budgets. Many companies in many countries developed magnesium fabrication techniques and trained craftsmen during the wartime periods. After the war was over, many of the wrought product producers went out of business due to the dropping of government support. Magnesium Technology 2002 Edited by H.I. Kaplan TMS (The Minerals, Metals & Materials Society), 2002 Dow continued in a lead role, with a number of other companies working hard to adapt the plants and knowledge of military products to peacetime. Some military programs in rolling and extrusions helped some businesses stay in operation. However, many companies tried to develop magnesium sheet and extrusions for boats, canoes, archery equipment, skis, ski boots, pianos, harps, delivery truck bodies, truck cabs, buses, trash collectors bins, racing boat hulls, private aircraft parts, fire truck hose containers, material handling equipment, dock boards, portable ramps, aerospace equipment parts, including rockets and satellites, radar tracking systems, electronic equipment cabinets, vibratory screens, tote bins, luggage frames and sides (Samsonite), ladders, water heater anodes, typewriters, rocket launchers and mortar bases, textile machinery parts, concrete buckets and hand finishing tools, jigs and fixtures and vibration testing machines. However, the increase of price of magnesium in the 1970’s had the effect of killing many of the smaller operations, and seriously affected the larger operations. Only in the past few years has there been a large scale, global interest in developing wrought products. This time it is led by private industry and hopefully will be more permanent than the previous efforts.