862

STEEL.— Bessemer Process.

TABLE I.

Transverse

No. of Bemelting.

Specific

breaking load,

Mean Ultimate

Gravity.

1 inch section,

Cl inches apart.

Deflection.

Inches.

6-969

490*0

1*440

8

7-025

491-3

1*753

10

7-108

566-9

1-620

18

7*385

312*7

0*479

CHEMICAL

ANALYSES.

No. of Remelting.

C.

Si.

s.

i

2-76

■77

*42

8

2*30

1 75

•60

10

3*50

1*98

•26

18

3*75

2-22

•75

The use of the cupola for melting the pig is notonly a great saving, but also facilitates the work, byturning out a greater quantity in a given time.

Within the last four years even the cupola hasbeen superseded, and manufacturers have to a largeextent found it possible to carry out Bessemer’soriginal idea, and take the metal in a molten statefrom the blast furnaces to the convertor. The meritof first practically carrying this out successfully withmovable convertors, is due to the talented manage-ment of the Terre Noire Works, France . Generallyit is not possible to place the convertors so near theblast furnaces that the metal can be run direct fromone to the other. An intermediate ladle is thereforenecessary; and as it usually has to travel over somedistance, it requires to bo mounted on a carriage.The ladle may either be tapped, as at Dowlais, ortipped and the metal poured at once into the vessels,as at West Cumberland Works. Both plans havetheir merits, the tipping being quickest done andrequiring no runner for the metal; the tapping cutsthe vessel lining out less, and allows less slag andscurf to enter the vessel. In both plans a singleladle has carried over 1000 tons of cast iron withoutrequiring relining. Fig. 12 is Dowlais’ tapping

Fig. 12.

ladle; A is the tap hole: Figs. 13 and 14 showthe arrangements of the West Cumberland tippingladle. Three ladles and carriages at West Cumber-land Works have now carried about 80,000 tonsof molten metal in the last two years, with scarcelyany repairs beyond relining with bricks and loam,and they appear to be capable of doing duty forsome years longer

The recent improvements in English Bessemerplant consist in making the casting pit shallower, insome cases doing all the work upon the level ground

Fig. 13.

Fig. 14.

(although in the writer’s opinion this latter plan isa doubtful advantage), and in increasing the radiusof the casting crane so as to make room for moremoulds. With larger and shallower pits there isnow no difficulty in making considerably over 1000tons of ingots per week in a pair of vessels inEngland; but this is still far behind the bestAmerican practice. The greatest output from apair of vessels that has been recorded up to thepresent time, has been that of the North ChicagoSteel Works, under Forsyth, recorded in Engineer-ing , March 22, 1878. The following are the par-ticulars :—Blowing began every Monday at 6 A.M.,and work was over for the week on Saturday at5 P.M., sometimes much earlier. No work onSundays, except ordinary repairs:—

1st heat, turned up Tuesday, January 1, at 6 a.m.

1372nd heat blown Friday, February 1, at 5-30 a.m.

Product of ingots for—

Tons.

5 Days ending Saturday, January 5,. 1489 ^ 0 ,

Week “ “ 12,.. .. 1797£rfo

“ “ “ “ 19.

“ “ “ “ 26.1767158g

■1 Days “ Thursday “ 31,. 1307^0,

Total for Month,.8100

Turns worked, 50.

Average product per turn,. 162

Heaviest 12 hours’ work, 30 heats,.176

Lightest “ “ 25 “ . lUJfog

Average life of bottoms used during month, 13 heats.

These results were obtained from a single pairof 5-ton convertors. The above steel was chieflyrolled into rails, of which the mill made duringthe month 6247||^J tons “ first class,” the “ secondquality” amounting to 1-9 per cent.: ninety-threemen and boys were actually employed in theBessemer department, of following nationalities:—