US2197098A

US2197098A - Mandrel

Info

Publication number: US2197098A
Application number: US114714A
Authority: US
Inventors: Davis Herbert; Pawol Joseph
Original assignee: National Tube Co
Current assignee: National Tube Co
Priority date: 1936-12-07
Filing date: 1936-12-07
Publication date: 1940-04-16
Anticipated expiration: 1957-04-16

Description

A ril 16, 1940.

H. DAVIS ET AL MANDREL Filed Dec. 7, 1936 0 0 m%% .H 1%. m5 HJ.

Patented Apr. 16, 1%40 watt PATENT orrica MANDREL Herbert Davis, Cleveland,

Ohio, and Joseph Pawol, Ellwood City, Pa., assignors to National Tube Company, a corporation of New Jersey Application December 7, 1936, Serial No. 114,714

5 Claims.

This invention relates to mandrels for metalworking operations and more particularly topiercing points and plugs for use in seamless tube mills.

fore, it has been impossible to successfully pierce solid billets made of high-chromium and highchromium-nickel alloys of the .stainless type, with piercing points made of low-chromiumnickel alloys. The conventional chromium-nickel piercing. points, upon repeated usage on short length billets; or single usage on long lengths of plain or alloy tubing; or single usage on stainless steel, fail by either distorting, burning on the nose, welding to the billet, picking-up metal or cracking from heat. The change in contour materially affects the quality of billet processed, power required, and may at times stall the machine and result in material damage.

Further, it has been impossible to use this conventional type 01' piercing point metal analysis on rotary rolling-mills or Stiefel expandingmills, wherein a finished wall-size isobtained, due to the necessity and difiiculty of machining the plugs to a close tolerance.

The novel mandrel of this invention is especially adaptable for use as a point or plug for piercing all workable plain and alloy steels or metals with a substantial increase in service over the chromium-nickel alloy piercing points heretofore used for both plain and alloy tubing.

The scaling and, physical properties of this alloy mandrel, piercing point or plug are, upon heat-treatment, of such character that it is capable of withstanding highthermal shock without deforming, welding, cracking or otherwise becoming useless for more than one operation in a sequence. This has been impossible with the high alloy type of tools heretofore used for piercing alloy steels of the high-chromium and high-chromium-nickel type, as this type of piercing point or plug requires preheating before use to reduce the thermal shock, andwas capable of piercing only one piece of material before deforming, welding or cracking, which renders it unfit for further use.

The physical properties of this alloy when properly heat-treated are exceptionally good, and

heat-treated tools formed of' this alloy may be shaped, forged, machined, ground or otherwise hot or cold formed without material change of its properties. These properties render the alloy adaptable for rotary rolling mill plugs which must be machined to a close tolerance.

Furthermore, with proper heat treatment, this alloy is free from hot or cold shortness and also from the so-called blue brittleness. which has long been the bane of points cast from the conventional chromium-nickel alloy irons or steels.

In the manufactureof pipes and tubes hereto- The scaling properties of this alloy mandrel are Iar superior to the chromium-nickel alloy type. When properly heat-treated, the scale is or a heavy, tightly adherent nature that Will not all oil in ordinary handling and, due to a unique property of the scale, when the tool is used it melts or fuses into a hard blue-black lustrous metallic coating which protects the tool during subsequent uses. I

The above and further objects will bu me apparent by referring to the following description and the accompanying drawing, in which:

Figures 1 through 6 are plans of pipe or tube mill piercing points which may be composed of the alloy of the present invention.

The piercing point or plug A of Figure l is of a type for use with a thirty-six inch roll piercing mill. The point A is composed of an integral casting of the special alloy to be described below and comprises a point portion 2, a tapered body portion 3, and a sleeve or neck portion l of less diameter than the body and adapted to receive the forward end of the plug-bar of the mill.

The piercing point or plug B of Figure 2 is another type ior use with the thirty-six inch roll piercing mill. The point B is generally of a smaller diameter than the point A and is for piercing smaller billets. The point B consists of a tapered body 5 and a neck or sleeve 6 having a core 1 which is extended into the body portion to receive the end of the plug-bar.

The plug or point C of Figure 3 is for use with a disk type of piercing mill and comprises a long tapered nose portion 9 and a body-portion Ill composed of a relatively short straight portion I2 and a rearwardly tapered portion l3. The

portion I3 is provided with a core [4 to receive the end of the usual plug-bar.

The plug or point D of Figure 4 is for use on a rotary rolling mill or Stiefel type cone ex- .pander and comprises an angular inlet section 5, a rolling section it and a cylindrical section H. The tool has a cored inlet i8, outlet i9 and chamber 2@. The cored section receives the plug supporting mandrel.

The plug or point E of Figure 5 consists of a curvilinear inlet or working section iii, a relief section 22 and core 23 to receive the bar cap.

The plug or point F of Figure 6 consists of a curvilinear inlet or working section 2 1, a relief section 25 and a chamber core section it to receive the bar and reduce the weight.

Plugs or points like the foregoing, or any other design of plug or point, for seamless mill operations, when made in accordance with this invention, are particularly adapted for processing plain or high-chromium or high chromiumnickel steel alloys of the stainless type or other alloy tubing.

Per cent Carbon .15 to .50 Manganese .40 to 1.50 Silicon .40 to 1.50 Chromium .50 to 2.50 Cobalt .50 to 2.50. Copper .50 to 2.50 Nickel .05 to 2.50' Phosphorus under .06 Sulphur under .06 Iron to make' 100.00

The plugs or points of this invention are cast from an alloy having the following range of analysis:

Other elements such as aluminum, titanium, zirconium, molybdenum, tungsten or vanadium may be added as desired.

A preferred specific alloy for the plugs or points has the following analysis:

Per cent Carbon .20 Manganese .75 Silicon 1.00 Chromium a 1.50 Cobalt 1.00 Copper 1.00 Nickel .50 Phosphorus .01 Sulphur .01 Iron to make 100.00

After the points or plugs are cast from the alloy above set forth, they are heat-treated by annealing in a closed furnace at a temperature between 900 degrees to 1000 degrees centigrade and preferably at approximately 950 degrees centigrade for approximately five hours and slowly cooled in the furnace. This heat treatment materially increases the physical properties of the points or plugs and forms thereon a close analysis:

Per cent Carbon .15 to .50 Manganese .40 to 1.50 Silicon .40 to 1:50 Chromium .50 to 2.50 Cobalt .50 to 2.50 Copper .50 to 2.50 Nickel .05 to 2.50 Phosphorus under.... .06 Sulphur under .06 Ir n Remainder annealing said piercing point at a temperature between 900 degrees and 1000 degrees centigrade and slowly cooling the same, whereby there is formed a. tightly adherent scale which melts or fuses when the piercing point is used.

2. The method of making a piercing point for tube mills which includes casting said piercing point from a ferrous alloy having the following analysis:

' annealing said piercing point at a temperature between 900 degrees and 1000 degrees centigrade and slowly cooling the same, whereby there is formed atightly adherent scale which melts or fuses when the piercing point is used.

3.The method-of making a piercing point for tube mills which includes casting said piercing point from a'ferrous alloy having the following analysis:

Per cent Carbon .15 to .50 Manganese .40 to 1.50 Silicon .40 to 1.50 Chromium .50 to 2.50 Cobalt r .50to' 2.50 C opper .50 to 2.50 Nickel; .05 to 2.50 Phosphorus under .06 Sulphur under .06 Iron; Remainder annealing said piercing point at a temperature of approximately 950 degrees centigrade and slowly cooling the same, whereby there is formed a tightly adherent scale which melts or fuses when the piercing point is used. 1

4. The method of making a piercing point for tube mills which includes casting said piercing point from a ferrous alloy having the following analysis: Per cent Carbon approximately Manganese approximately .75 Silicon approximately"--- 1.00 Chromium approximately 1.50 Cobalt approximately 1.00 Copper approximately 1.00 Nickel approximately .50 Phosphorus under .06 Sulphur under .06 Iron Remainder annealing said piercing point at a temperature of approximately 950 .degrees centigrade and slowly cooling the same, whereby there is formed a tightly adherent scale which melts or fuses when the piercing point is used.

5. The method of making a piercing point for tube mills which'includes casting said piercing point from a ferrous alloy having the following analysis:

Per cent Carbon .15 to .50 Manganese .40 to 1.50 Silicon .40 to 1.50 Chromium .510 to 2.50 Cobalt .50 to 2.50 Copper .50 to 2.50 Nickel .05 to 2.50 Phosphorus under .06 Sulphur under .06

Iron Remainder annealing said piercing point, and slowly cooling the same, whereby there is formed a tightly adherent scale which melts or fuses when the viewing is used- JOSEPH PAWOL.

HERBERT DAVIS.

' Percent Carbon approximately .20 Manganese approximately .75 Silicon approximately; 1.00 Chromium approximately 1.50 Cobalt approximately 1.00

Copper approximately 1.00 Nickel approximately .50 Phosphorus under L. .06 Sulphur under .06 Iron". Remainder