US1808957A - Manufacture of seamless tubes - Google Patents

Description

June 9,.1931..

w. KUNST I MANUFACTURE OF SEAMLESS TUBES Filed April 4. 1927 Patented- June 9, 1931 UNITED STATES PATENT OFFICE WILHELM KUNS'I, F BARMEN, GERMANY, ASSIGN'OR T0 HEINRICH ESSEROF HILDEN, GERMANY."

SEAMLESS TUBES Application filed April 4, 1927, Serial No. 181,010, and in Germany January 17, 1927.

i My invention relates to the manufacture of seamless tubes by rolling and has for its object to simplify and expedite the production.

It has already been proposed to produce seamless tubes from a tubular blank by roll ing it out upon a roughing and a coggin mill and finishing rolls, a reducing mill eing provided between the cogging and the'finishing trains in which the billet or ingot coming from the cogging mill is reduced in diameter.- In this way a large number of passes can be saved in the finishing rolls.

The present invention differs fundamentally from the foregoing in that the thick walled tubular blank is reduced to a thinner Wall in a piercing mill, the ingot bein then reduced to the desired diameter in a re ucing rolling mill, and then rolled out to the final wall-thickness in a two-high rolling mill.

In the drawings aflixed to this specification and forming part thereof, the invention is illustrated diagrammatically by Way of example. i

In the drawings Fig. 1 shows a piercing mill 1, and mandrel 2 in the course of reducing the Wall thick- 'ness of a thickwalled tubular blank 3,

- Fig. 2 illustrating a reducing rolling mill 4 and the tubular workpiece 5 whose outer dianiieter is reduced to the extent finally desire Fig. 3 shows a two high mill 6 and the workpiece 7 in the course of having its wall thickness further reduced, the workpiece being at the same time stretched to assume its final length Without its outer diameter being changed.

Obviously a blank of predetermined great wall-thickness can thus be converted into a tube of any inferior wall-thickness by adding or removing the respective passes and mandrels. v

In this way not only is the process of production shortened and simplified, but the construction of the whole plant for carrying it out is also simplified. In the place of the roughingjand cogging millsa piercing mill is employed, whereby a whole rolling set is saved. Reheating of the blank before the by rolling, comprising reducing the wall thickness of a comparatively thick-Walled tubular blank, thereafter reducing the diam eter of the said blankto the final diameter 5 and thereafter reducing the wall thickness of saidblank to the final'thickness.

2. The process of producing seamless tubes by rolling, comprising reducing the wall thickness of a comparatively thick-walled 'tubularblank in a piercing mill, thereafter reducing the diameter of the said blank to the final diameter in a reducing mill and thereafter reducing the wall-thickness of said blank to the final thickness in a twohigh rolling mill.

In testimony whereof I afiix my signature.

WILHELM KUNST.

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