Military purposes were among the first major markets for aluminum. The metal made it possible to reduce the weight of soldiers’ equipment, and quickly spread to new areas. It was the main ingredient in the explosive Ammonal, which was frequently used during World War I. It became commonly used in cartridge and grenade casings, but the real breakthrough came in another weapon branch.
At the beginning of the 20th century, the German metallurgist Alfred Wilm invented an alloy with high mechanical strength. It was named Duraluminium, after Wilm’s workplace, the German company Dürener Metall Werke. The alloy was strong enough for self-supporting structures and revolutionized the development of aircraft. This made aluminum one of the most strategic commodities during World War II.
During the occupation of Norway, the aluminum industry helped increase the production of aluminum to support the German war machine. This made facilities exposed to Allied bombing and sabotage by the Norwegian resistance.
The Occupiers' Grandiose Plans
Before the war, the Norwegian aluminum company Naco, which Nordisk aluminum in Holmestrand were a part of, had been central to the planning of a Norwegian fighter aircraft production. In collaboration with Strømmens' Verksted, the American fighter Curtiss Hawk was scheduled to be produced under license. The plans were approved by the Norwegian parliament in the autumn of 1939.
Nordisk aluminum in Holmestrand was among the first companies to be placed under German administration. Ten days after the attack on Norway on April 9, 1940, a delegation of Nazi leaders and German industry came to the plant. Luftwaffe needed large quantities of aluminum to replace shot-down aircrafts, and Norway was designated as the Third Reich's aluminum producer. The Luftwaffe leader, Herman Gøring, drew up plans to dramatically increase Norwegian production.
The occupiers invested heavily in power generation and smelting plants, and the Holmestrand plant was set to produce duralumin for the German aircraft industry. "Silent sabotage" made the work difficult, but in 1944 the Germans achieved their goal. The communist resistance group Saborg carried out a sabotage operation in September 1944. This put a final stop to the production of aircraft materials in Holmestrand.