Reference has already been made to the relation between the chemical constitution and the mechanical properties of mild steel, the difficulties surrounding the problem of ascertaining exactly what that relationship is, and of estimating the ultimate strength of a given sample from an analysis of its chemical constituents. The resulting formula, arrived at after an exhaustive examination of the subject by an eminent American authority, has also been given on p. 12.

The following examples of chemical analyses are given, not by way of elucidating the formulae above referred to (they are, for this purpose, insufficient in number), but as practical examples of the form of analysis met with in ordinary work, and were made on the same constructive material, the mechanical tests of which have been given in the preceding tables. The chemical analysis and the mechanical test were in all cases made from the same test piece.

The variations to be observed are those usually found in practice.

1. Chemical Analysis Of Sample Representing" Mild Steel Plate

Tensile test of the above sample -

Ultimate strength, 28.1 tons per square inch.

Elongation, 30.0 per cent, in 8 inches. Bending tests satisfactory.

2. Chemical Analysis Of Sample Representing ½" Mild Steel Plates

Tensile tests of the above sample - Ultimate strength, 27.5 tons per square inch.

Elongation, 25.0 per cent, in 8 inches.

26.0 Mean ultimate strength, 27.9 tons per square inch. Mean elongation, 25.5 per cent, in 8 inches. Bending tests satisfactory.

3. Chemical Analysis Of Sample Representing" Mild Steel Plate

Tensile test of the above sample -

Ultimate strength, 26.6 tons per square inch.

Elongation, 31.0 per cent, in 8 inches. Bending tests satisfactory.

4. Chemical Analysis Of Sample Representing ½" Mild Steel Plate

Tensile test of the above sample -

Ultimate strength, 27.7 tons per square inch.

Elongation, 28.0 per cent, in 8 inches. Bending tests satisfactory.

5. Chemical Analysis Of Sample Representing Mild Steel Plate

Tensile test of the above sample -

Ultimate strength, 29.8 tons per square inch.

Elongation, 27.0 per cent, in 8 inches. Bending tests satisfactory.

6. Chemical Analysis Of Sample Representing Mild Steel Flat

Tensile test of the above sample -

Ultimate strength, 28.4 tons per square inch.

Elongation, 31.0 per cent, in 8 inches. Bending tests satisfactory.

7. Chemical Analysis Of Sample Representing 12" X 1/2" Mild Steel Flat

Tensile test of the above sample -

Ultimate strength, 28.7 tons per square inch. Elongation, 29.5 per cent, in 8 inches. The amount of sulphur in this sample is somewhat large, but in other respects the composition is normal, and the bending tests were satisfactory.

8. Chemical Analysis Of Sample Representing 5" X 5" X ¾ " Mild Steel Angle

Tensile test of the above sample -

Ultimate strength, 29.1 tons per square inch.

Elongation, 28.9 per cent, in 8 inches. Bending tests satisfactory.

9. Chemical Analysis Of Sample Representing 3½" X 3" X ½" Mild Steel Angle

100.000 Tensile test of the above sample -

Ultimate strength, 29.2 tons per square inch.

Elongation, 24.0 per cent, in 8 inches. Bending tests satisfactory.

10. Chemical Analysis Of Sample Representing 3" X 3" X ½" Mild Steel Angles

Tensile test of the above sample -

Ultimate strength, 28.5 tons per square inch.

Elongation, 25.0 per cent, in 8 inches. Bending tests satisfactory.

11. Chemical Analysis Of Sample Representing 3" X 3" X ½' Steel Angles

Tensile test of the above sample -

Ultimate strength, 29.2 tons per square inch.

Elongation, 24.0 per cent, in 8 inches. Bending tests satisfactory.

12. Chemical Analysis Of Sample Representing 3" X 3" X ½" Steel Angles

Tensile test of the above sample -

Ultimate strength, 28.7 tons per square inch.

Elongation, 23.5 per cent, in 8 inches. Bending tests satisfactory.

13. Chemical Analysis Of Sample Representing Mild Steel For Rivets

Tensile test of the above sample - Ultimate strength, 26.1 tons per square inch. Elongation, .28.4 per cent, in 8 inches.

14. Chemical Analysis Of Sample Representing 7" X ½" Flats

Tensile test of the above sample -

Ultimate strength, 28.0 tons per square inch.

Elongation, 22.0 per cent, in 8 inches. Bending tests satisfactory.

15. Chemical Analysis Of Sample Representing 2½" + ⅜" Flats

Tensile test of the above sample -

Ultimate strength, 28.80 tons per square inch. Elongation, 31.0 per cent, in 8 inches.

Bending tests satisfactory.

16. Chemical Analysis Of Sample Representing 2½" + 2½" Angles

Tensile tests of the above sample -

Ultimate strength, 29.3 tons per square inch. Elongation, 25.0 per cent, in 8 inches. Ultimate strength, 27.8 tons per square inch. Elongation, 24.0 per cent, in 8 inches.

17. Chemical Analysis Of A Sample Representing ½" Thick Mild Steel Plate

Tensile tests of the above sample - Lengthways, Ultimate strength, 28.6 tons per square inch.