An alloy widely used for making parts of machinery, and also for artistic purposes, is the so-called Delta metal. This is a variety of brass hardened with iron; some manufacturers add small quantities of tin and lead; also, in some cases, nickel. The following analysis of Delta metal (from the factory at Düsseldorf) will show its usual composition:

 

II III

IV

V

Copper....

55.94

55.80 55.82

54.22

58.65

 

41.61

40.07 41.41

42.25

38.95

Lead......

0.72

1.82 0.76

1.10

0.67

 

0.87

1.28 0.86

0.99

1.62

Manganese

0.81

0.96 1.38

1.09

....

Nickel.....

traces.

traces.

0.06

0.16

0.11

Phosphorus

0.013

0.011 traces.

0.02

I is cast, II hammered, III rolled, and IV hot-stamped metal. Delta metal is produced by heating zinc very strongly in crucibles (to about 1600° F.), and adding ferromanganese or "spiegeleisen," producing an alloy of 95 per cent zinc and 5 per cent of iron. Copper and brass and a very small amount of copper phosphate are also added.