Transparent Mold, Showing Relative Positions of Core, Casting, Sprue, Etc.
| Alloy | Tensile Strength | Number of Blows | Total Foot Pounds |
|---|---|---|---|
| Cast Iron | 23,400 | 7 | 102 |
| Semi-Steel | 35,050 | 11 | 206 |
| Malleable Cast Iron[[8]] | 37,140 | 22 | 1,580 |
| Cast Steel[[8]] | 72,120 | 92 | 10,112 |
[8]. On account of bending, the malleable iron and the steel bars had to be turned several times.
Semi-steel is a very close-grained alloy of ten or twelve thousand pounds per square inch greater strength than cast iron. It is a most satisfactory material for medium and larger sized castings for which cast iron formerly was used.
Cast Iron Tee, Cock Plugs, and Return Bends, with Sprues and Gates Attached
Did we say that cast iron was very brittle? So it is, comparatively speaking. But just as the chemist will tell you that there are no substances which are absolutely insoluble, just so does cast iron appear to be extremely brittle only when compared with the iron alloys of considerably less brittleness.
The three pictures of the hooped and twisted casting illustrate how unwise it might be to speak with absoluteness. A few years ago the casting illustrated on pages [190] and [192] was brought to this country by a visitor to Europe, with an expression of regret that cast iron produced in this country did not have such qualities of elasticity as had cast iron made abroad. Whereupon, without any change whatever in his iron mixture or cupola practice, the superintendent of a well-known foundry made castings which were exact duplicates of that submitted. The three photographs shown further on (Figs. A, B, C) were of one of these castings. The ability to bend without breaking is, of course, largely due to the shape.
Plugs and Wheels as They Come from the Mold
Occasionally as many as 200 castings can be made in one mold.