Induction Heating
History of Ajax Magnethermic
The AJAX name was adopted as a trade-mark when Francis J. Clamer founded the Ajax Metal Company in Philadelphia in 1880, a company organized to manufacture a newly developed bronze alloy -- the first leaded bearing bronze the market--and in the manner of the time, the design of a head representing Ajax was used with this trademark. The reasons for choosing Ajax are obscured by the dust of time. Research into Greek mythology has shown that there were two heroes named Ajax, both fighting before Troy. Of these, it is the so-called "Lesser" Ajax who had a slight connection with electricity: he got killed by lightning. The lightning was faithfully used in two early Ajax trademarks. At one time, Ajax had this head modeled as a display for the Foundry Show and other exhibits and some of the old-timers may still remember this head at the center of the Ajax display, slowly rotating on a turntable, from time to time it sported a cigarette dangling from it's mouth, put there by playful salesmen. (I doubt that Rowan did this.)
Dr. Guilliam H. Clamer was the son of Francis J. Clamer, founder of Ajax Metal. Dr. Clamer graduated from the University of Pennsylvania in 1897 as a chemist and was one of the first to combine his chemical knowledge with the science of metals - the profession of metallurgist which was then almost unknown. While still a student, he was instrumental in pioneering chemical control at his father's plant for the production of controlled composition brass and bronze ingot. In time, Dr. Clamer became president of his father's company, and it was in this capacity that he constantly sought new and more economical ways of melting metals and producing new alloys. Whenever he became convinced that a certain design for a melting furnace would prove economical and practical, he persuaded the originator to join him in the venture and formed an affiliate company to produce the specific furnace.
Working at the Ajax Metal Company, where brasses and bronzes were melted in conventional crucible furnaces -- which were not only uneconomical but also a health hazard (without accurate temperature control metal would easily overheat releasing the lower melting point zinc as a vapor which caused nausea. the so-called ~ "zinc shakes").
The Ajax Metal Company undertook in 1912 the development of an electric furnace. Dr Carl Hering, a prominent electrical engineer in Philadelphia, believed the "pinch phenomenon," which he had discovered accidentally a few years previously, could be usefully applied to electric furnace operation. The Ajax Metal Company backed him in his endeavor to successfully produce a furnace operating upon the principle underlying the "pinch phenomenon."
The solenoid effect of an alternating field is to repulse a conductor. In a single turn U-shaped liquid metal loop as the secondary of a transformer the force would be equal in both directions and therefore would pinch and open the loop.
Dr. Hering, in spite of Dr. Clamer's early suggestion of inducing current in a resistor, persisted in his idea of supplying power to his furnace through electrodes which ultimately proved impractical. The search then turned to utilizing the induction principle.
James R. Wyatt conceived the idea of building a refractory lined container with a channel (loop) at the bottom. He had first-hand knowledge of all the problems a new electric furnace would have to solve. Combined with the use of the newly discovered induction principles this knowhow was the basis for the development of the Ajax-Wyatt furnace -- a highly practical tool for melting brasses and bronzes. Ajax have in the library the original log book of Mr. Wyatt's first nineteen experiments conducted between July, 1915, and February. 1916, to establish channel design and transformer characteristics for the new furnace. The use of V-shaped "wishbone' and round channel configurations, the problems of transformer design and cooling as well as practical melting problems in the concise language of the furnace logs and sketches make fascinating reading.
During the years 1916 to 1920, while the Ajax Wyatt submerged resistor furnace was introduced to industry, Dr. Clamer continued his search for the ideal melting furnace, and especially for the efficient conversion of electrical energy into heat for melting. It was his search for basic explanations of the phenomena involved that brought him to his association with Dr. E.F. Northrup, one of the foremost physicists of the day and then a professor at Princeton University.
Edwin Fitch Northrup was born in Syracuse, New York, in 1866. At the time he became associated with Ajax, he had already accomplished more than many people do in a full life time. After receiving college degrees at Amherst and John Hopkins, where he received his doctor in physics in 1895, he worked for some time as an assistant to Professor H.A. Rowland in the development of the multiplex printing telegraph system and eventually became Chief Engineer of the newly founded Rowland Printing Telegraph Company. In 1903, he joined Morris E. Leeds to form the Leeds @ Northrup Company, and for seven years was immersed in the development of ac measuring methods, electrical conduction, and magnetic effects. For example, the Type K potentiometer was a joint Leeds & Northrup invention. In 1910, he returned to academic life as a professor of physics at Princeton where he remained until 1920,when he joined Ajax. In between, in 1916, he also founded the Pyro-electric Instrument Company of Trenton, New Jersey.
The high frequency induction furnace was born at Princeton's Palmer Laboratory Dr. Clamer, not satisfied with Dr. Hering's use of the pinch effect", enlisted Dr. Northrup's services for a fundamental study of converting electrical energy into heat. The conclusion was that the use of high frequency currents was possible and Dr. Northrup designed the first high frequency induction furnace and operated it in the laboratory at Princeton.
The patent examiner in Washington could not believe the claims Northrup made and had rejected the application as "Inoperable" The Ajax patent attorney arranged a demonstration for the examiner at Princeton: an earthenware pot wound with several turns of ordinary lamp cord with a piece of metal inserted in the pot. As Dr. Northrup energized this furnace, the metal became red, then white, and finally formed a molten pool. Convinced, the patent examiner allowed a patent with very broad claims, the foundation for the business of a new Ajax company: The Ajax Electrothermic Corporation of Trenton, New Jersey.
Dr. Northrup was persuaded to leave Princeton and head the new company and for twenty years continued to spark the development of the high frequency induction furnace from a small laboratory curiosity to an important industrial tool. However, the first years were devoted mainly to finding an appropriate power source to supply the high frequency current necessary to operate the furnace. On Dr. Northrup's initiative, and with the cooperation of Dr. Steinmetz, the General Electric Company embarked on the development of the motor generator. Once this was achieved, there was almost no limit to the applications for the new furnace. Modern electronics was born, for instance, at Westinghouse, using the induction furnace in the manufacture of vacuum tubes. The Alnico magnet was developed using the Ajax-Northrup furnace and its capability of rapidly and accurately alloying metals and maintaining their composition. Vacuum melting was an early development and so was precision casting. Induction hearing for forming and for surface hardening were developed. Carbide-tipped tools could be developed thanks to the induction furnace. The list is long and these are only brief examples.
During the twenties and early thirties gained a firm foothold in many sectors of the metal working industries in the United States, their reputation also began to travel overseas, to England and the industrial countries of Europe, and to Japan. These were the circumstances under which a life-long association began between the Ajax companies and Manuel Tama, who was at that time, Director of Research for one of the largest German copper and brass mills.
Manuel Tama was born in 1893 in Guayaquil, Ecuador, a lively tropical port city, the son of a lawyer active in the country's turbulent political life. Early in life, he was sent to Europe for his education, first to Italy and Switzerland, later to Germany where he graduated from college and married. Thus, from early youth on, he was away from his homeland and only returned for visits. After his graduation, he remained at the university for a short time, engaged in industrial design work; this led to his move to the new copper and brass mill he had helped to plan, where he became Director of Research. It was in this capacity that he persuaded his company to use the new Ajax induction furnaces and also to manufacture and sell them to German industry. At the same time he conducted basic research on the characteristics of induction furnaces and their further development. Later, he became an independent representative for Ajax furnaces throughout Europe and spent most of his time travelling and visiting customers, at the same time becoming involved in many of the major metalworking developments, particularly the concept of continuous casting which he followed from its early beginnings. Since this process was closely related to aluminum, he was soon searching for a new efficient aluminum melting furnace. This led him to tests with the Ajax-Wyatt channel furnace. The major problem in milting aluminum in this furnace type was the formation of oxide deposits in the narrow channel section which resulted in clogging and reduced metal circulation. In the Ajax-Wyatt furnace, it was necessary to completely empty the furnace and then pull a special chain through the channel to remove these oxides. Manuel Tama designed a new induction furnace with straight vertical channels which could be cleaned with simple scraping tools while the metal remained in the furnace. This he did during the time he had his headquarters in Switzerland, and a first furnace, tested in cooperation with the Swiss Aluminum Company (now Alusuisse), proved successful.
The year was 1940: the world stood on the brink of World War II. Totalitarianism reigned in Germany and Italy and the Civil War in Spain--where Mr. Tama and his family had lost much of their possessions--and ended in dictatorship. Against this background, he decided to leave Europe and begin a new life in the United States. Dr. Clamer had watched the development of the new induction furnace--now called the "Ajax-Tama-Wyatt" furnace--and saw in it a new tool of great the next years, the new channel furnace was introduced to aluminum and zinc diecasting plants of the automotive companies (with General Motors, as always, being the leader) small gasoline engines (Johnson Motors was the pioneer), and appliance manufacturers. Aluminum billet casting shops were introduced to increasingly larger melting units. Soon, large furnaces were used for melting zinc and pure copper, a new design was invented for continuous galvanizing lines, and a continuing development in automatic pouring of metals resulted, first, in an electromagnetic pump, later the first air-pressure operated AJAXO-MATlC unit, and finally the automatic pouring of high temperature copper alloy castings. Large drum furnaces with detachable inductors, furnaces operating under protective gas, special melting-holding systems for large diecasting plants, and many other custom designs were part of the daily realities.
Also, as a result of his continuing contacts to overseas. Mr. Tama brought the coreless line frequency induction furnace to the United States under license from an old acquaintance, Otto Junker, of Germany, who had pioneered this development.
During World War II, strong emphasis was placed on the development of the light metals for the aircraft and transportation industries. Mr. Tama foresaw this trend and was one of the incentives for developing the Ajax-Tama-Wyatt furnace. At the same time, the semi-continuous and fully continuous casting of aluminum was perfected giving birth to an entire industry. After the war, new uses of light metals for peacetime production were sought. Extruding aluminum billets into shapes used in the manufacture of window frames and doors and other producers for the building and home industries provides the answer. It was in this field that the new idea of 60-cycle induction heating of aluminum billets for extrusion was born and actually gave birth to the Magnethermic Corporation. The company was formed in the kitchen of Mr. John A. Logan, together with Mr. John Taylor and Mr. Robert Lackner. Mr. Logan's next door neighbor. Mr. "Bus" Covington, a young attorney just out of the Navy, assisted in the drawing up of the legal papers. This was in April. 1948.
Mr. Bruce McArthur who joined the company in 1951 as Chief Engineer recorded:
"After organizing the company these young men apparently had a bit of a sales problem. For three months the records show no orders and report only discussions of sales and promotion ideas. But then, on August 21, 1948, comes the notation that they were about to enter into a contract with their first customer, Youngstown Manufacturing, for a billet heater. Then, on October 16, Mr. Logan advised the Board of Directors that the furnace was ready for delivery. How is that for a record--completely new design, first of its kind, designed and built in less than two months!"
"The basic patent covering the design of the first induction heater was signed by John Logan, Bob Lackner and Vic Winkle. Vic Winkle was a very practical man who had a motor repair shop on Andrews Avenue in Youngstown. It was there the first heaters were built. I remember it well: It was in 1951, when Bob Lackner left, that I joined the organization. The Engineering Department consisted of one small office, kind of hung from the ceiling on some shaky beams. John Taylor, who was the Sales Manager, was a big husky 200-pounder and delighted in bouncing up the steps. The whole room shook as though it would fall down."
"With more orders coming in, things changed rapidly. In 1951, Magnethermic moved into new plant on Simon Road, in 1953, the company received its first million-dollar order for, the US Air Force and to build the equipment an addition was made to the plant and more employees hired. An active development program headed by ML Nick Ross soon expanded the business into the heating of other metals--brass, copper, steel -- and into heat treating. The Market expanded beyond the American continent. Already, in 1951a license agreement was made with Loewy Engineering who henceforth sold their extrusion presses together with Magnethermic billet heaters in England and throughout Europe. In the mid-fifties, large billet heaters were shipped to Japan and to many other countries"