Patent application number | Description | Published |
20080289388 | Piercing-rolling method and piercing-rolling apparatus for seamless tubes - [Objective] To provide a method and apparatus for seamless tubes in which the occurrence of material peeling can be prevented even when the skew angle δ and tube expansion ratio are increased. | 11-27-2008 |
20090064748 | Process for manufacturing a seamless tube - A high quality hollow shell in which the occurrence of internal surface flaws caused by the rotary forging effect and/or shear deformation is prevented by suppressing the rotary forging frequency and shear deformation in a transient region at the stage of billet gripping and a worsening of thickness deviations in the top portion of the hollow shell is also prevented is reliably produced with preventing miss-rolling such as incomplete billet gripping and troubles in bottom withdrawal and an increase in the outer diameter of the hollow shell in the bottom portion. A billet is pierced while being rotated and advanced to produce a hollow shell, from which a seamless tube is finally manufactured, using a pair of skew rolls, a pair of disk rolls, and a plug under such conditions that each of the ratio (Dg/d) of the diameter Dg of the gorge portion of the skew rolls and the outer diameter d of the billet, the ratio (Dd/d) of the diameter Dd of the groove bottom of the disk rolls and the outer diameter d of the billet, the ratio (Dd/Dg) of the diameter Dg and the diameter Dd, the inlet face angle θ | 03-12-2009 |
20090064752 | PROCESS FOR STRAIGHTENING TUBE AND METHOD FOR PRODUCING TUBE THEREWITH - In straightening a tube using a roll straightening machine provided with drum type straightening roll pairs vertically opposingly disposed, at least an outer layer portion of a roll main body is made of elastic material having spring type hardness Hs (JIS K 6301 A type) of 50 to 100 in at least three pairs of straightening rolls on an outlet side of the roll straightening machine, and an offset amount is imparted to a tube engaged in the three pairs, at least, of straightening opposing rolls such that η defined by an equation (1) ranges from 1.0×10 | 03-12-2009 |
20090301155 | Method of manufacturing seamless pipes - Seamless pipes excellent in quality features with high productivity is made by a by carrying out piercing-rolling using a piercer provided with a pair of inclined rolls. The piercing-rolling is carried out under conditions such that the plug tip draft (TDFT) or the root of the product of the plug tip draft (TDFT) are controlled along with the number of billet revolutions (N), namely (TDFT×N) | 12-10-2009 |
20110067475 | Process for Producing High-Alloy Seamless Tube - A starting material to be extruded made of a high alloy comprising, in mass %, Cr: 20 to 30% and Ni: more than 22% and 60% or less is heated to a temperature predetermined according to the contents of Mo and W and is subjected to a hot-extrusion process, the heating temperature T (° C.) satisfying a relationship of Formula (1), (2), or (3), which is expressed in terms of the average cross-sectional area A (mm | 03-24-2011 |
20120210761 | Plug, Piercing-Rolling Mill, and Method of Producing Seamless Tube by Using the Same - A plug includes a front edge portion having a convex curvature; a cylindrical portion having a truly or nearly cylindrical shape; a trunk portion having an outer diameter gradually increasing toward a rear edge thereof; a mandrel joint provided in a rear edge portion of the plug; a lubricant ejection hole running through the trunk portion from the mandrel joint that opens on the surface of the cylindrical portion; and a coating comprising oxides and Fe that is formed on the base metal surface of each of the front edge portion as well as the trunk portion by arc spraying using an iron wire. In this way, the plug can prevent inner surface flaws from occurring in a hollow blank that is deformed by piercing-rolling, and can extend its life without requiring a long time for making it. | 08-23-2012 |
20120304724 | METHOD FOR STRAIGHTENING TUBE AND STRAIGHTENING ROLL - A method for straightening a tube by using an asymmetric roll, which has different diameters D | 12-06-2012 |
20130115376 | ANTIOXIDANT AGENT, PROCESS FOR PRODUCING ANTIOXIDANT AGENT, AND PROCESS FOR PRODUCING METALLIC MATERIAL - There is provided an antioxidant agent capable of preventing scale from being produced on the surface of a heated metallic starting material more effectively than the conventional antioxidant agent. The antioxidant agent according to the present invention contains a plurality of glass frits having different softening points and an inorganic compound having a melting point not higher than 600° C. The inorganic compound mainly softens in the low-temperature range of about 600° C. The plurality of glass frits mainly soften in the low-temperature range of about 600 to 1300° C. Therefore, the antioxidant agent covers the surface of metallic starting material in a broad temperature range, oxidizes the surface of metallic starting material, and prevents the production of scale. | 05-09-2013 |
20130283879 | Ni BASE ALLOY PIPE STOCK AND METHOD FOR MANUFACTURING THE SAME - A method for manufacturing an Ni base alloy pipe stock comprises piercing and rolling a billet by use of Mannesmann piercing and rolling mill. The pipe stock has controlled amounts of C, Si, Mn, P, S, Cr, Ni, Mo, W, Cu, Al, N, with the balance being Fe. With the method, the following equations are satisfied, wherein values of T | 10-31-2013 |
Patent application number | Description | Published |
20080314109 | Plug for use in piercing mill - A plug has a tip end portion, a taper portion, and a middle portion. The surface of the tip end portion is a spherical surface whose radius of curvature is R | 12-25-2008 |
20090038359 | Method of manufacturing seamless pipe or tube - A billet is provided on a pass line between a pusher and a plug, and the billet is advanced and caught between a plurality of inclined rolls. At least between when said caught billet contacts said plug and when the piercing and rolling reaches a steady state, the advancing speed of the billet is not less than the advancing speed of the billet when the piercing and rolling is carried out without pushing the billet forward by the pusher in the steady state. By this manufacturing method, inner surface defects at a tip end of a hollow shell can be restrained. | 02-12-2009 |
20100011831 | PIERCING MILL - A piercing mill includes a plurality of inclined rolls, a plug, a pusher, and an undriven guide roll. The pusher pushes a round billet from the rear end at least until the round billet advances for a prescribed distance after contacting the inclined rolls. The guide roll is between the inclined rolls and the pusher and includes a roll shaft and a roll surface, with the roll shaft arranged obliquely with respect to a pass line PL. The sectional shape of the roll surface is a concave arch shape. The round billet is rotated by the guide roll and the friction force generated when the round billet contacts the inclined rolls is reduced. Consequently, the wear of the inclined rolls can be restrained if the round billet is pierced and rolled while it is pushed in between the inclined rolls using the pusher. | 01-21-2010 |
20100089111 | Piercer, Plug and Method of Manufacturing Seamless Pipe or Tube | 04-15-2010 |
20100107714 | PUSHER DEVICE FOR PIERCING AND ROLLING AND METHOD OF MANUFACTURING SEAMLESS PIPE OR TUBE USING THE SAME - A pusher device | 05-06-2010 |
20100175450 | METHOD OF PRODUCING SEAMLESS METAL TUBE AND PUNCH FOR USE THEREIN | 07-15-2010 |
Patent application number | Description | Published |
20130202803 | ANTIOXIDANT AGENT AND PROCESS FOR PRODUCING METALLIC MATERIAL - There is provided an antioxidant agent excellent in anti-dripping property and anti-peeling property. The antioxidant agent in accordance with the present invention contains a plurality of glass frits having different softening points, potter's clay, and bentonite and/or sepiolite. On account of the potter's clay, the antioxidant agent applied to the surface of a metallic starting material is less liable to drip down. Further, on account of the bentonite and/or sepiolite, the antioxidant agent is less liable to peel off the surface of the metallic starting material. | 08-08-2013 |
20140245806 | METHOD OF PRODUCING SEAMLESS METAL PIPE - A method of producing a seamless metal pipe, which can suppress the occurrence of lamination defects, is provided. A method of producing a seamless metal pipe according to an embodiment of the present invention includes the steps of: heating a high alloy containing, by mass %, Cr: 20 to 30% and Ni: more than 22% and not more than 60% in a first heating furnace (S2); piercing-rolling the high alloy heated in the first heating furnace with a first piercing machine to produce a hollow shell (S3); heating the hollow shell in a second heating furnace (S4); and elongation-rolling the hollow shell heated in the second heating furnace with the first piercing machine or a second piercing machine which is different from the first piercing machine (S5). | 09-04-2014 |
20140250965 | METHOD OF PRODUCING SEAMLESS METAL PIPE - A method of producing a seamless metal pipe, which can suppress the occurrence of inner surface flaws, is provided. A method of producing a seamless metal pipe according to an embodiment of the present invention includes the steps of: heating a high alloy billet BL containing, by mass %, Cr: 20 to 30% and Ni: more than 22% and not more than 60% in a heating furnace F | 09-11-2014 |
20140260494 | PIERCING APPARATUS, PLUG USED FOR PIERCING APPARATUS, AND METHOD FOR PRODUCING SEAMLESS STEEL PIPE - There is provided a piercing apparatus in which the occurrence of an inner surface flaw in a hollow shell is suppressed. A piercing apparatus ( | 09-18-2014 |