Section 5. Wartime Research and Production
Item 5. Research on Alternative Steel
Nickel supplies became extremely tight across the globe as a result of the outbreak of the Second World War in September 1939 and exports to Japan were interrupted. As a result, the Ministry of Commerce and Industry issued regulations on August 20, 1940 restricting the use of nickel, and emergency standards on alternative steels that use limited amounts of nickel were adopted. Alternative steels were manufactured within Japan based on those standards.
List of attendees at nickel chrome steel alternatives conference in the Japan Society of Mechanical Engineers journal
On March 19, 1941, the Machinery Materials Department of the Japan Society of Mechanical Engineers and the Automotive Steel Materials Research Center of the Iron and Steel Institute of Japan held a combined symposium to discuss alternatives to nickel chrome steel with a focus on automotive steels.1 During the meeting, the use of chrome molybdenum steel in place of nickel chrome steel was discussed.
The United States also experienced a nickel shortage, and the American Iron and Steel Institute issued a pamphlet entitled 'Possible Substitutes for Nickel Steels' as a countermeasure. Kiichiro submitted an abstract of an article on this problem for the June 1942 issue of Journal of the Japan Society of Mechanical Engineers.2 In this way, research on steels was conducted by making reference even to foreign publications.
Toyota Motor Co., Ltd. conducted research on heat treatments of each steel type with the aim of switching to a different steel. Specific areas of research included the transformation temperature, quench hardening ability, tempering ability, and other characteristics of steels with different compositions and properties depending on the temperature, the effects of different masses on quenching hardness and depth according to the size and thickness of the material, quenching deformation, and so on. In 1941, a switch was made from nickel chrome steel to chrome molybdenum steel.
Later, molybdenum also became scarce, and it became necessary to switch from chrome molybdenum steel to chrome steel. This problem was resolved around 1943. Research was also conducted on switching from alloy steels to carbon steel for some components, and a shortage of chrome steel necessitated testing on the practicality of switching to all-carbon steel.
As a result of this research, the properties of various steels were determined, making it possible to use the steel best suited for the application. Although they were first referred to as alternative steels, when used in appropriate applications, they were no longer simply alternatives.3