Monday, Mar. 19, 1945

Axis Armor

It is possible to wage war in spite of severe shortages of strategic metals; the Germans have been doing it for five years. The Japs are not troubled by the problem; they have plenty of strategic metals. These hard facts were reported last week by U.S. metallurgists who have analyzed captured enemy war materiel for Dr. Vannevar Bush's OSRD.

With test tube and spectroscope, the metallurgists reconstructed a revealing picture of arms-making inside the Axis countries. The Germans started the war with meager supplies of copper, nickel, molybdenum, vanadium, chromium, manganese--all considered vital for war. They showed great skill and ingenuity in finding workable substitutes. As early as 1934 they began to make shell cases of copper-coated steel instead of brass (which uses more copper). As war ate up their copper stocks, they shifted to electrolytic copper plating (a thinner coat), finally to a rust-retarding lacquer coating containing no copper at all.

Lacking nickel for hardening steel in armor plate, they first substituted chromium and molybdenum alloys, then used thin sheets of steel bonded together, which require much less alloy for hardening than does a single thick plate. The analysis showed the Germans used their small supply of alloy metals again & again, by painstakingly sorting the scrap from their wrecked armor, according to its alloy content.

But the metallurgists' detective work proved that in some metals the Germans have been less badly off than supposed. They have had enough tungsten, for example, to shoot it away in armor-piercing projectiles.

The biggest surprise in the study was the apparent plentifulness of Japanese strategic metal supplies. The Japanese are wasteful and often clumsy in workmanship (e.g., apparently ignorant of the principles of stresses in metals, they weaken airplane connecting rods by making deep stencils of serial numbers in them). But the Japs have not had to be careful. They have enough copper to make their cartridge cases of brass, have been lavish in the use of nickel, zinc, manganese, aluminum and other precious alloys.

To a metallurgist, a piece of metal often bears its own trademark. Even after it is melted down and mixed, he can tell, by close study of alloys and traces of other elements present, just where the metal came from. The metallurgists' analysis of Jap materials identified one source of the abundance: "a considerable part" of the metal now killing U.S. fighting men came from the scrap which the U.S. sold to Japan before the war.

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