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

Per cent.

Carbon ... ... ... ... ...

0.200

Silicon ... ... ... ... ...

0.019

Sulphur

0.064

Phosphorus

0.046

Manganese

0.565

Iron (by difference)

99.106

100.000

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 " Mild Steel Plates

Per cent.

Carbon • • • ••• ... .. •••

0.178

Silicon • • • ••• • • • ••. •

0.014

Sulphur

0.074

Phosphorus

0.049

Manganese...

0.497

Iron (by difference)

99.188

100.000

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

Per cent

Carbon

0.220

Silicon

0.014

Sulphur

0.069

Phosphorus

0.050

Manganese ...

0.497

Iron (by difference)

99.150

100.000

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 " Mild Steel Plate

Per cent.

Carbon

0.178

Silicon

0.014

Sulphur

0.060

Phosphorus

0.056

Manganese ...

0.450

Iron (by difference)

99.242

100.000

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

Per cent.

Carbon

0154

Silicon

0.011

Sulphur ... ... ... ......

0.084

Phosphorus

0.059

Manganese...............

0.454

Iron (by difference)

99.238

100.000

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

Per cent.

Carbon ... ... ... ... ...

0.201

Silicon

0.003

Sulphur

0.035

Phosphorus

0035

Manganese ...

0.650

Iron (by difference)

99.076

100.000

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

Per cent.

Carbon

0.170

Silicon ... ... ... ... ...

0.015

Sulphur ... ... ...

0.079

Phosphorus

0.043

Manganese...

0.720

Iron (by difference)

98.973

100.000

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 " Mild Steel Angle

Per cent.

Carbon ••• ••• ••• ••• •••

0.116

Silicon ... ... ... ... ...

0.023

Sulphur

0.034

Phosphorus

0.042

Manganese . ... ... ... ... ...

0.684

Iron (by difference)

99.101

100.000

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 3" X 3" X " Mild Steel Angle

Per cent.

Carbon ... .... ... ... ....

0.165

Silicon

0.061

Sulphur

0.060

Phosphorus

0.063

Manganese...

0.360

Iron (by difference)

99.291

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 " Mild Steel Angles

Carbon

Per cent. 0.316

Silicon

0.053

Sulphur

0.053

Phosphorus

0.056

Manganese......

0.360

Iron (by difference)

99.162

. ■

100.000

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 ' Steel Angles

Per cent.

Carbon

0.198

Silicon

0.072

Sulphur

0.047

Phosphorus

0.062

Manganese...

0.342

Iron (by difference)

99.279

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.

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

Per cent.

Carbon

0.200

Silicon ••• .•• ••• ... •••

0.080

Sulphur

0.069

Phosphorus

0067

Manganese...

0.468

Iron (by difference)

99.116

100.000

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

Per cent.

Carbon ••• ••« • •« ••• • • •

0.130

Silicon •.• ••• ••• ••• »••

0.026

Sulphur

0.055

Phosphorus

0.056

Manganese...

0.360

Iron (by difference)

99.373

100.000

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 " Flats

Per cent.

Carbon

0.174

Silicon ••• ••• ... ... • • •

0.009

Sulphur ...

0.074

Phosphorus

0.038

Manganese...

0.547

Iron (by difference) .........

99158

100.000

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 2" + ⅜" Flats

Per cent.

carbon .... ... ••• •• ...

0176

Silicon ... ••• ••• ••• • • •

0.010

Sulphur

0.073

Phosphorus

0.042

Manganese...

0.688

Iron (by difference)

99.011

100.000

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 2" + 2" Angles

Per cent.

Carbon ••• ••• ... ••• •••

0.169

Silicon ••• • • • • • • • • •••

0.026

Sulphur

0.083

Phosphorus

0.050

Manganese ...

0.410

Iron (by difference)

99262

100.000

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 " Thick Mild Steel Plate

Per cent.

Carbon

0.190

Silicon

0.020

Sulphur

0.072

Phosphorus ............

0.064

Manganese ...

0.612

Iron (by difference)

99.042

100.000

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