The Robert-.Bessemer Converter, Fig. 8, is described in F. Lynwood Garrison's report on the Metallurgical Arts at the Paris Exhi bition (Journal Franklin Institute, 190), which see.
What is claitned as novel in the converter is a combination of several parts in a con verter having a flat sIde, in which flat side are ranged the tuyeres in a plane horizontal to the axis of the converter, and all in the same plane." The tuyeres having an inclination to enable a rotary motion to be imparted to the metal bath, and being so disposed that by tilting the converter in the trunnions the depth of the metal over the tuyeres can be regulated." It seems to have produced excellent results wherever put in operation and to he the only side-blown converter which is suitable for the basic process, as the large amount of slag produced would soon choke up a similar fixed converter.
Processes for prevendinv Piping of k•ivel In gots.—Reeent processes for preventing pip ing are thus described by Mr. T. S. Crane, in a paper published in the Trans. A. S. M. E., Vol. X. Strenuous efforts have been made, and by many different modes, to prevent the piping of cast-steel ingots, but it is only recently that a simple apparatus has been perfected for . practically accomplishing this object.
Some of the most modern means hereto fore used are mentioned below. The '‘ Sweet " process consists in putting powdered char coal upon the top ()f the ingot when poured, to prevent its upper end from oxidation. and, by its combustion, to maintain the fluidity of the steel, and thus assist in filling the pipe as it forums. The entire effect it very slight. The compression process used by Whitworth to form sound steel ingots has never been wholly successful, as it operated to consolidate the exterior of the casting without permitting the free discharge of the gases from its interior ; and while it has operated to prevent the forma tion of a pipe or local depression, it has been liable to produce a spongy or porous casting. Various modifications of Whitworth's plan have been devised. S. T. Williams has devised a compression process for making sound circular ingots for saw plates. The comparatively
thin and flat form of such ingots permits the sides to lie bent or crushed inward, while the interior of the ingot is still at a welding heat, and this effects the desired purpose ninth bet ter than in a square ingot, where the compression of the sides would tend to induce cracks, as the metal, when first crystallized, is not very tenacious. In experiments tried by William II. Hinsdale. at the Jersey City Steel Works, in the year 1884, it was found that a pressure of 300 lbs. per sq. in., operating upon a 24-in, piston, and concentrated upon the end of a 3,1 in.-square ingot, merely produced an ingot containing innumerable globules of gas.
The "Billings and Hinsdale" process provided a reservoir at the top of the mold, and a movable plunger within the mold, by which the steel was drawn downward to make an ingot, which would be fed during the shrinkage period by the residue remaining in the reservoir. This process is not, therefore, convenient except for the casing of large ingots. Mr. Hinsdale also experimented at the Jersey City Steel Works with a pressure of 60,000 lbs. per sq. in. upon the metal. The result was the shortening of the ingot from 25 to 22 in. in length, and perfect solidity, except that the pipe appeared in the same form, a flaw, as it ordinarily displays itself at the piped end of a forged bar. Mr. Hinsdale thus found that piping, or its effects, could not be eliminated by pressure, and invented a perforated plug to insert in the mold upon the top of the fluid metal, through the perforation in which the gases might escape while appljing the pressure.
With this device the top of the ingot became slightly chilled, and a crust formed thereon ; but after the pressure upon the metal was raised to about 20,000 lbs. per sq. in., the crust of metal exploded with a loud report, and a eircular piece like a boiler punching shot out of the perforation in the plunger, followed by all the gases, and sufficient metal to fill the cavity and form a stud as long as one's little finger, on top of the ingot.