Iron With Cold Brittleness

A great authority on iron metallurgy in Sweden (and Europe) was Sven Rinman (Chapter 8, Iron, section 8.7.2). In his Mining and Metallurgical Dictionary (Bergiverks-lexikon) he had described a method to determine whether a specific iron was Hkely to be brittle at about 200°C. This cold brittleness is caused by a high content of phosphorus in the iron. Sefstrom himself described the method in the Transactions ofThe Royal Swedish Academy of Sciences in 1830  

Some years ago the inspector [bei mastare] Rinman described a method with which it is easy to detect the disposition for cold brittleness in iron. The method is founded on the fact that iron of that sort, after etching with hydrochloric acid, gives a black powder. 

The black powder consists of almost insoluble phosphides. This simple method seems to have very little to do with the discovery of vanadium. Sefstrom s use of the method and his ability for critical analysis, however, was of decisive significance. 

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Tho best way to try the quality of cast-iron is to Strike its edge with a hammer. Should the blow make a slight impression, the iron must be in some degree malleable, and, if tho specimen be uniform, it may be regarded as good for machinery if, on thg contrary, tho hammer make no impression, and fragments fly off, the iron is brittle, and, consequently, bad. The soft cast-iron yields readily to the file after the outer crust has been romoved, and is, in a cold state, slightly malleable. 

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