US1516153A - Process and apparatus for producing hollow steel bars - Google Patents

Description

mvq i9 J. P. GORMAN ET AL PROCESS ANDy APPARATUS FOR PRODUCING HOLLOW STEEL BARS Filed Jan. 9, 1920 2 Sheets-Sheet l Nov. 18, 1924 l,56,53

J. P. GORMAN ET AL PROCESS AND APPARATUS FOR PRODUCING HoLLow STEEL BARS Filed Jan. 9. 1920 I 2 SheeS-Sheet 2 ATTU/M/EY Patented Nov.. I8, 1924.

JAMES rAUL'GomuAN, or WATERVLIET, AND HENRY FRANK wE-GLARZ, or conoEs,

NEW YORK. i

PROCESS AND APPARATUS FOR PRODUCING HOLLOW STEEL BARS.

Application filed January 9, 1920. Seria] No. 350,440.'

To all whom t may cmwem: o Be it known that we, JAMES PAULGOR- MAN andlI-IENRY FRANK WEGLARZ, citizens of the United States, and residents, respectively, of VVatervliet and Cohoes, in the the metal to the breaking down and reduc- .y

ing action of the hammeror rolls.

In ordinary practice, steel is first run into ingots or blooms and is then subjected to 'a reducing process by annealing and forging or rolling to break up the segregated form of structure produced incasting the molten metal and reducing the crystalline structure of the metal to a proper form with the carhides in solution.

In forming seamless tubes, the operation is-even more complicated, as the blooms of metal must first be perforated and drawn down, until they canbe gripped by dies and worked through drawing dies and over mandrels on the draw-bench. There are, of 3 5 course, the requisite annealing operations to keep the metal in condition for drawing.

So far as is known to applicants it has not been a practice to produce hollow steel bars with walls of any desired thickness, purely 40 by a rolling and reduction process,with the usual annealing of the metal, in contradistinction to drawing the metal through a die.

' It is the object of the present invention to produce hollow steel bars havin' the same structural form for any given feormulae'of analysis, as is found in bar steel reduced in the usual manner of annealing forging and rolling. v

It is a further object of the invention, as

a step in the process of producing hollow steel bars, to cast hollow ingots, which may be subsequently subjected to the necessary forging and rolling operations, to bring up the yrequisite structural form of the steel.

Obviously hollow steelbars have almost an indefinite field of usage permittingithe manufacture of hollow o shafting, hollow bolts and hollow bars for tools and fixtures vof various sorts where lightness` and the strength of steel is re uired.

The process hereina r defined makes it possible to. produce hollow steel evenv for gun barrels, with the bore approximately to size, or at an rate requiring only the finishing cut an the rifling- This obvia-tes the expensive and arduous operation of boring through the solid bar. The structural form, of the steel, that is, its microstruct-ure will be the same as though a solid bar had been rolled and bored. The advantages are apparent from the above brief reference.

Referring to the drawings: Fig. 1 is a view of a mould illustrating the manner of casting the hollow ingot. Fi 1a is a plan view.

ig. 2 lillustrates anl ordinary rolling mill and a means of handling the ingots and core during the rolling operation, for the difj'ferent passes.

Figs. 3, 4 and 5 illustratemore in detail the apparatus shown in plan in Figure 2.

In carryin out the process we employ an ingot mould of the usual type or we may employ a sand mould. In fact, the type of mould for the ingot is not material. In pouring the molten steel into the mould we providea core 10, of metal which is sur.

rounded by va. tubular core piece or tube 11, ofba refractory material such as a brick-dust tu e. i

Theuse of the metallic core-bar, with the covering of refractory material prevents the steel from welding to the core-bar and makes it possible to readily remove the corebar when the ingot has chilled.

It willbe observed that the core is merely a composite structure having. an iron or steel inner core, with the brick tube or similar refracto covering against which the metalmay s rink.

The ingots so cast, if examined microscopically would show the usual cast structure common to molten metals cooled down after being poured.

The ingots thus formed are now annealed to a forging heat and are swedged out under the hammer in the usual manner except that a core of steel or iron is inserted in the cored opening of the ingot.

the bars through the rolls.

The" core indicated at 12, is rotated by any suitable means such as the chuck 13, attached to the motor shaft 14, of the motor 15, and is constantly rotated, throughout the swedging and hammering operations `upon the ingot. A

After being suitably reduced, the bars' are now heated to a. rolling temperature-"and the hollow bars are given several passes through the rolls of the rolling mill R, until the desired size of bar has been attained.

During each rolling operation a cold mandrel is employed and is rotated during the reduction processing of the bar.

'lhe size of the core-bar determines, of course, the size of opening, through the steel bar and it is apparent that the core-bar must .be of sufiicient length to .permit of the elongation of the bar due to the rolling operation.'

As illustrated in the drawing the motor 15, may be under-slung from a carrier 16, runnin upon a track 17, parallel with the axes 'of the rolls of the rolling mill R, so that the bars may be shifted from one roll to another during the di'erent passes.

'llhe carrier for the motor also has a movement axially in line, with the movement of |llhis provides for feeding the core with the bar as the latter passes through the rolls. 'lhe motor or other desired devices constantly rotates thecore bar during the rolling of the hollow bar.,

@f course, the bars, during the rolling operation, are from time to; time annealed so that they will take the necessary reduction without cracking or scaling.

llt will be 'quite apparent that the crosssectional form of the steel bars will depend upon the form of groove employed in the rolls and the invention applies as; well to round, square, hexagonal, octagonal or any other form required.

llf desired a comparatively large core-bar may be employed in the initial steps of re` duction and core-bars of' lesser diameter may be used after each reduction, j

-lln some instances, this has been found ad'- vantageous particularly wherea'comparatively small tubular opening is required, with unusually thick surreundingwalls of metal.

'lhe useof mandrels of different sizes will bring the entire body of the metal into an intimate reduction field `so that the' entire lmetal structure will be homogenous and .quired Working temper and are ready for machining, or use such as soli-d bar might require. y

'.lhe steel, formed into hollow hars as dea corresponding -mandrels and feeding them may be mo Lerares `taining a definite interior diameter and with the rolls working upon the exterior of the bar, there is actually a double reduction force applied in any given pass of the metal through the rolls. rllhe core forms a solid backing against which the steel of the ingot or bar 1s swedged by the rolls so that the entire body of the metalcomes within the influence of the swedging or reducing action. Obviously the mechanism for holdin the dified to suit the erigencies of any particular requirement without departing from the spirit or intent of the invention, which broadlyl stated contemplates produ'cin a hollow ingot and maintaining an opening of definite size therethrough, during the swedging and rolling operations to Secure the proper character of reduction of the metal.

l/lhen it is desired -to produce a hollow bar having a non-cylindrical opening therethrough, it is possible to use a core bar of any desired cross-section.

'.lhis is made possible by using a hollow core bar and injectinga cooling medium therethrough.

'lhe cooling medium may, -of course, be either a liquid or Huid, such as chilled air or gas, so long as it will maintain a reduced temperature in the core bar.

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Very low temperature air will absorb the Where a core'bar of angular cross-section or non-cylindrical section is employed, the bar is simply fed in an axial direction as the steel bar is lpassed through the rolls. @bviously it .would be quite'impossible to rotate the core bar within the steel underreductidn. A

lFrom the above it is apparent that the invention has an extremely wide application either, tothe production, of hollow steel bars, having a cylindrical inner and outer surface or to hollow steel bars having a cylindrical bore and an Kirregular exterior surface or to bars having both the bore and exterior surface of irregular cross-section.

lll/hat we claim as our invention and desire to secure by Letters Patent is 1. 'llhe method ofl producing hollow steel bars which consists in casting a hollow steel ingot, annealing the same and forging over a metallicv core-bar, and. further reducing the structure of the steel by rolling the hollow bars upon metallic core-bars.

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2. An apparatus for producing hollow steel bars which 'consists of rolling means for reducing the bars b successive passes, means for supporting anc rotating a core-bar within the steel bar during each rolling operation, means permitting shifting of the core-bar into axial line corresponding to each pass through the rolls, and means permitting advancing the core-bar axially during each rolling' operation.

JAMES PAUL GORMAN. HENRY FRANK WEGLARZ.

Witnesses:

ALFRED S. ROWLES, JOHN H` MACKLE.

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