TABLE 3.--COMPARISON OF PHYSICAL PROPERTIES BETWEEN AIR, OIL AND WATER-HARDENED STEEL HAVING CHEMICAL ANALYSIS IN PERCENTAGE OF ------------------------------------------------------------------------- Carbon 0.24 Manganese 0.30 Phosphorus 0.035 Sulphur 0.035 Chromium 12.85 Silicon 0.20 ------------------------------------------------------------------------- | Hardened | | Elastic | Tensile | | Hardening| from, | Tempered | limit, |strength,|Elongation|Reduction medium | degrees |at, degrees| per lb. |lb. Per | in 2 in. |of area, |Fahrenheit|Fahrenheit | sq. in. | sq. in. | per cent |per cent ---------|----------|-----------|---------|---------|----------|--------- | | 930 | 158,815 | 192,415 | 13.0 | 40.5 | | 1,100 | 99,680 | 120,065 | 21.0 | 59.2 Air | 1,650 | 1,300 | 70,785 | 101,250 | 26.0 | 64.6 | | 1,380 | 66,080 | 98,335 | 28.0 | 63.6 | | 1,470 | 70,785 | 96,990 | 27.0 | 64.7 ---------|----------|-----------|---------|---------|----------|--------- | | 930 | 163,070 | 202,720 | 8.0 | 18.2 Oil | 1,650 | 1,100 | 88,255 | 116,480 | 20.0 | 56.9 | | 1,300 | 77,950 | 105,505 | 25.5 | 63.8 | | 1,380 | 88,255 | 98,785 | 27.0 | 66.3 ---------|----------|-----------|---------|---------|----------|--------- | | 930 | 158,815 | 202,050 | 12.0 | 34.2 Water | 1,650 | 1,100 | 90,270 | 120,735 | 22.0 | 59.8 | | 1,300 | 66,080 | 102,590 | 25.8 | 64.8 | | 1,380 | 67,200 | 97,890 | 27.0 | 65.2 ------------------------------------------------------------------------- This steel can be drawn into wire, rolled into sheets and strips and drawn into seamless tubes. CORROSION.--This steel like any other steel when distorted by cold working is more sensitive to corrosion and will rust. Rough cut surfaces will rust. Surfaces finished with a fine cut are less liable to rust. Ground and polished surfaces are practically immune to rust. When chromium content is increased to 16 to 18 per cent and silicon is added, from 2 to 4 per cent, this steel becomes rust proof in its raw state, as soon as the outside surface is removed. It does not need to be heat-treated in any way. These compositions are both patented. S. A. E. STANDARD STEELS