Abstract: According to an example embodiment, a method is provided including: decoding, at a base station of a wireless system, one or more bits of an uplink transmission from a user equipment, wherein the one or more bits are indicative of a channel quality; calculating a confidence metric corresponding to a reliability of the decoding; and causing a channel quality report to be generated based at least on the calculated confidence metric and a value for each system configuration parameter in a limited set of one or more system configuration parameters associated with the base station.

Abstract: Described herein are methods for producing a hot forged material in air using a Ni-based superalloy for the die. Also described herein are methods for producing a hot forged material, by placing on a lower die a material for hot forging, of which part or all of the surface is coated with a glass-based lubricant, and pressing the material for hot forging with the lower die and an upper die, to form a hot forged material, wherein one or both of the lower die and the upper die are made of a Ni-based superalloy, and wherein the surface of the die in contact with the material for hot forging is coated with a glass-based lubricant containing SiO2 as a main component, in which the total content of alkali metal oxides is 0 to 10.0% in mass %.

Abstract: Monitoring apparatus for monitoring a condition of an aqueous metalworking fluid comprised of water and a lubricant, of a metalworking fluid circuit of a metalworking machine, wherein the at least one measurement element of the apparatus is remote from the metalworking fluid circuit. Method for determining a condition of a metalworking fluid, and, when required, to add water and/or lubricant to the metalworking fluid circuit.

Abstract: The present disclosure is directed towards different embodiments of additively manufacturing and smoothing an AM preform to configure an AM preform for downstream processing (working, forging, and the like).

Abstract: The present invention relates to a composition for cooling a propulsion system of an electric or hybrid vehicle including at least one battery, comprising: (i) at least one base oil or at least one hydrocarbon-based fluid with a boiling point of greater than or equal to 50° C.; (ii) at least one fire retardant corresponding to formula (I) RF-L-RH??(I) in which RF is a perfluorinated or partially fluorinated group, RH is a hydrocarbon-based group, and L is a linker; and (iii) at least one fluoro compound with a boiling point of between 50 and 250° C. The invention also relates to the use of at least one fluoro compound with a boiling point of between 50° C. and 250° C. for promoting the contact between a fire retardant corresponding to formula (I) and an element of a propulsion system of an electric or hybrid vehicle, when thermal runaway is observed, said fire retardant of formula (I) being formulated in a base oil, or a hydrocarbon-based fluid with a boiling point of greater than or equal to 50° C.

Abstract: To provide a hot forging die made of a Ni-based superalloy, which is free from any deteriorations in working environment and die shape during hot forging in the air, and also provide a manufacturing process for a forged product using the same and a manufacturing process for a hot forging die. The hot forging die includes: a base body made of a Ni-based superalloy consisting of, by mass, 10.3 to 11.0% of W, 9.0 to 11.0% of Mo, and 5.8 to 6.8% of Al and balance of Ni with inevitable impurities; and a coating layer of inorganic material that is formed on at least one of a forming surface and a side surface of the die and contains 30 mass % or more in total of one or more of Si, Cr, and Al out of Si and metal elements.

Abstract: A covered electrical wire including a conductor and an insulating coating layer covering an outer periphery of the conductor, in which the conductor is a twisted wire obtained by concentrically twisting together a plurality of elemental wires constituted by a copper alloy, the copper alloy contains one or more elements selected from Fe, Ti, Mg, Sn, Ag, Ni, In, Zn, Cr, Al, and P in a total amount of 0.01 mass % to 5.5 mass % inclusive, and the remaining portion includes Cu and inevitable impurities, and an amount of oil adhering to a surface of a central elemental wire disposed at a central portion of the twisted wire is 10 ?g/g or less with respect to the mass of the central elemental wire.

Abstract: A covered electrical wire including a conductor and an insulating coating layer covering an outer periphery of the conductor, in which the conductor is a twisted wire obtained by concentrically twisting together a plurality of elemental wires constituted by a copper alloy, the copper alloy contains one or more elements selected from Fe, Ti, Mg, Sn, Ag, Ni, In, Zn, Cr, Al, and P in a total amount of 0.01 mass % to 5.5 mass % inclusive, and the remaining portion includes Cu and inevitable impurities, and an amount of oil adhering to a surface of a central elemental wire disposed at a central portion of the twisted wire is 10 ?g/g or less with respect to the mass of the central elemental wire.

Abstract: A dynamically impacting method comprising simultaneously peening a substrate surface and forming a thin film of metallic glass on the substrate surface for increasing the surface hardness, fatigue resistance, anti-fracture toughness and corrosion resistance of the substrate simultaneously.

Abstract: A method of producing a forged product is described, in which a forging component is hot-forged using a lower die and an upper die. The method includes a first process in which at least a part of an die face of the lower die is covered with a first glass lubricant; a second process in which the lower die is heated; a third process in which at least a part of the forging component is covered with a second glass lubricant; a fourth process in which the forging component is heated to a temperature that is higher than a heating temperature of the lower die in the second process; and a fifth process in which the forging component is placed on the die face of the lower die and hot forging is performed using the lower die and the upper die.

Abstract: A burnishing machine is provided in which both sides of a groove is machined by a single tool without changing the movement direction of a piston. The burnishing machine, includes: a tip configured to press and process a process face; and a pressurizing unit configured to press the tip against the process face, the pressurizing unit including, a piston configured to reciprocate in a direction orthogonal to the tip, a cylinder portion that accommodates the piston such that the piston reciprocates; and a pressurizing mechanism configured to urge the tip to the process face at both timing of pushing the tip against the process face and pulling the tip against the process face by making the piston reciprocate.

Abstract: Provided are polishing compositions comprising a water-soluble polymer and water. The water-soluble polymer of an embodiment has a repeat unit that does not have any hydroxyl groups, and the water-soluble polymer has a hydroxyl group content in a range of 4 mmol/g or higher and 21 mmol/g or lower. The water-soluble polymer of another embodiment has a repeat unit A that has a hydroxyl group and a repeat unit B, and the number of moles of the repeat unit B in the total number of moles of all the repeat units of the water-soluble polymer is 5% or greater.

Abstract: One embodiment of a method of refining alpha-phase grain size in an alpha-beta titanium alloy comprises working an alpha-beta titanium alloy at a first working temperature within a first temperature range in the alpha-beta phase field of the alpha-beta titanium alloy. The alloy is slow cooled from the first working temperature. On completion of working at and slow cooling from the first working temperature, the alloy comprises a primary globularized alpha-phase particle microstructure. The alloy is worked at a second working temperature within a second temperature range in the alpha-beta phase field. The second working temperature is lower than the first working temperature. The is worked at a third working temperature in a third temperature range in the alpha-beta phase field. The third working temperature is lower than the second working temperature. After working at the third working temperature, the titanium alloy comprises a desired refined alpha-phase grain size.

Abstract: A method for bending a thin-walled tube to form a small radius bend on the thin-walled tube includes providing a die, lubricating the thin-walled tube, extruding the thin-walled tube, and thrusting elastomer fillers. A die defining a curved cavity enclosed within is provided. The curved cavity is configured to receive the thin walled tube. The thin-walled tube is lubricated using an antifriction coating material applied on an exterior surface of the thin-walled tube for reducing friction between the exterior surface of the thin-walled tube and the curved cavity of the die. The thin-walled tube is extruded into a curved section from an insertion end of the die. The elastomer fillers are thrusted into an inner surface of the thin walled tube via a mandrel. The mandrel is forced against the thin-walled tube to prevent damage of the inner surface of the thin-walled tube to form the small radius bend.

Abstract: The invention relates to a method for producing seamless pipes of heated massive metal blocks, by means of a mandrel (4), which is fastened on a rolling rod (5), in the case of which a coating material is applied onto the inner side of the hollow block (3) during the forming process by means of the influence of the rolling rod (5) from the massive metal block to a hollow block (3), which is created during the forming.

Abstract: A method for rolling rolling stock, wherein a water-based cooling lubricant is applied to the rolling stock and/or to at least one roller which forms a roll gap, at least one water-soluble and tribologically active additive being added to the water-based cooling lubricant prior to application to the rolling stock and/or to the at least one roller.

Abstract: A system and method of processing an alloy ingot or other alloy workpiece to reduce thermal cracking and reduce friction between the workpiece and the forging die may generally comprise positioning a multi-layer pad between the workpiece and the forging die. An article for processing an alloy ingot or other alloy workpiece to reduce thermal cracking also is disclosed. The present disclosure also is directed to an alloy workpieces processed according to the methods described herein, and to articles of manufacture including or made from alloy workpieces made according to these methods.

Abstract: The invention relates to a method for preparing metal workpieces for cold forming by first applying a phosphate layer and then applying a lubricant layer which has a major content in organic polymer material. The phosphate layer is formed by an aqueous acidic phosphating solution having a major content in calcium, magnesium or manganese and phosphate. The lubricant layer is formed by contacting the phosphated surface with an aqueous lubricant composition which has a content in organic polymer material based on ionomer and optionally also non-ionomer the organic polymer material used predominantly being monomers, oligomers, co-oligomers, polymers or copolymers based on ionomer, acrylic acid/methacrylic acid, epoxide, ethylene, polyamide, propylene, styrene, urethane, the ester or salt thereof. The invention also relates to the corresponding lubricant composition, to the lubricant layer produced thereof and to its use.

Abstract: A process for the coating of surfaces of a metallic component to be formed by contacting the surfaces of the metallic component prior to forming operation with an aqueous composition containing 80% by weight of at least one organic film-forming ionomeric polymer or copolymer, whereby the total organic polymeric material has an average acid number in the range from 20 to 300, optionally at least one further organic film-forming polymer different from the organic film-forming ionomeric polymer or copolymer; optionally a neutralizing agent; a low temperature corrosion inhibiting cross-linking agent and water. The pH of the aqueous composition at the beginning of the coating process is in the range from 6 to 10.5.

Abstract: A status monitoring system for accurately determining the contaminant water concentration in a lubricant oil used in a rolling device includes a contaminant water concentration monitoring device configured to monitor the contaminant water concentration in the lubricant oil. The contaminant water concentration monitoring device includes an electrostatic capacitance detector and an oil temperature measuring instrument, which are configured to detect the electrostatic capacitance and the oil temperature of the lubricant oil, respectively, and a water concentration calculation section configured to calculate the contaminant water concentration from the detected electrostatic capacitance and oil temperature in accordance with a predetermined rule.

Abstract: Forge lubrication processes are disclosed. A solid lubricant sheet is placed between a workpiece and a die in a forging apparatus. Force is applied to the workpiece with the die to plastically deform the workpiece. The solid lubricant sheet decreases the shear friction factor for the forging system and reduces the incidence of die-locking.

Abstract: 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).

Abstract: 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 F1 (S2); piercing-rolling the high alloy billet BL heated in the heating furnace F1 with a piercing machine P1 to produce a hollow shell (S3); cooling the hollow shell and then reheating the hollow shell in the heating furnace F1 (S4); and elongation-rolling the heated hollow shell with the piercing machine P1 (S5).

Abstract: In a drawing method of a metallic tube which includes: filling a high-pressure container with a lubricating oil, the container having a mother tube inserted thereinto; pressurizing the oil with a pressure booster; and drawing the forcedly lubricated mother tube, the oil having a kinetic viscosity of 100 to 2000 mm2/s at 40° C. and at normal pressure and a viscosity pressure coefficient of 15 to 24 GPa?1 at 40° C. is used for preventing seizing and vibrations in drawing and for suppressing the deterioration of surface roughness due to oil pits in tube. Herein, the oil preferably contains one or more of extreme-pressure (EP) additives in a total amount of 10 mass % or more, being selected from a sulfur-based additive, a chlorine-based additive, an organic calcium metallic salt, a phosphorus-based additive, an organic zinc-based additive, and an organic molybdenum-based additive, each having a prescribed amount of relevant element.

Abstract: A closed loop coolant system which ensures the isolation of coolant fluid within an apparatus for producing a metal container by wall ironing. The apparatus includes a die toolpack which reduces the thickness of the container side wall, a ram (5) and a ram guidance assembly (10) which guides the ram along a bore of a tubular assembly. The tubular assembly has a fluid inlet, and the surface of the bore of the tubular assembly has grooves (13) for passage of coolant fluid between the bore and around the outside of the ram (5) and seals for minimizing leakage of oil into the coolant. Coolant is directed back to a tank (20) via a heat exchanger (21) and any oil is skimmer off the coolant by an oil skimmer (24). This oil can then be filtered, cleaned and recycled, or disposed of.

Abstract: Provided herein are compositions comprising at least one estolide compound of formula: in which n is an integer equal to or greater than 0; m is an integer equal to or greater than 1; R1, independently for each occurrence, is selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; R2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R3 and R4, independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched. Also provided are uses of the compositions described herein.

Abstract: Provided is a lubricant for metal working comprising a vinylidene compound having 12 to 64 carbon atoms obtained by oligomerizing ?-olefins, having 4 to 20 carbon atoms, using a metallocene catalyst. The lubricant for metal working is excellent in a workability and a surface detergency property and has a high flash point and can reduce environmental pollution.

Abstract: A method for rolling rolling stock, wherein a water-based cooling lubricant is applied to the rolling stock and/or to at least one roller which forms a roll gap, at least one water-soluble and tribologically active additive being added to the water-based cooling lubricant prior to application to the rolling stock and/or to the at least one roller.

Abstract: A lubricating oil composition for metal working, including a base oil composed of one or more selected from mineral oils and synthetic oils and having a kinematic viscosity at 40° C. of 50 to 300 mm2/s, and 0.

Abstract: An elongated steel element adapted for the reinforcement of rubber products is covered with a ternary alloy or quaternary alloy coating of copper-M-zinc. M is one or two metals selected out of the group consisting of cobalt, nickel, tin, indium, manganese, iron, bismuth and molybdenum. The copper content inside the coating ranges from 58 weight percent to 75 weight percent. The content of the one or two metals inside said coating ranges from 0.5 weight percent to 10 weight percent. The remainder is zinc and unavoidable impurities. The one or two metals are present throughout the coating. Phosphorus is present on and/or in the coating in an amount of more than 1 and less than 4 milligram per square meter of the coating. The coating further comprises one or, ore compounds which complex with the copper in the coating to form an insoluble film on its surface. Good results are obtained for steam ageing and cured humidity adhesion.

Abstract: A device for lubricating the cylinders of a roll stand, in particular for roll nip lubrication in a roll stand for strip-shaped rolling stock. A mixture of water and oil is produced by a mixing and spraying device (1). The mixture is sprayed onto at least one of the cylinders (2) of the roll stand and/or to the surface of the rolling stock (3). The mixing and spraying device (1) include an arrangement of several nozzle mixer units (4). Water is guided thereto by a first supply line (5) and oil is guided thereto by a second supply line (6).

Abstract: The invention provides a water-soluble metal-working oil agent, including a component A and a component B, wherein the component A is a mineral oil which has a characteristic temperature, as measured in accordance with JIS K2242, of 570° C. or higher, and the component B is at least one condensed fatty acid which is selected from a condensed fatty acid (1), produced through dehydration condensation of a hydroxycarboxylic acid, and a condensed fatty acid (2), produced through dehydration condensation of an alcoholic hydroxyl group of the condensed fatty acid (1) with a monovalent carboxylic acid, which has a characteristic temperature, as measured in accordance with JIS K2242, of 650° C. or higher. The agent can provide excellent workability with a hard-to-work material and can prolong tool life.

Abstract: The invention relates to a method for preparing metal workpieces for cold forming by applying a lubricant layer either to a metal surface or to a metal surface which has been pre-coated with e.g., a conversion coating. The lubricant layer is formed by contacting the surface with an aqueous lubricant composition which has a content in at least one water soluble, water-containing or water-binding oxide or silicate and a content in organic polymer material, the organic polymer material used predominantly being monomers, oligomers, co-oligomers, polymers and copolymers based on ionomer, acrylic acid/methacrylic acid, epoxide, ethylene, propylene, styrene, urethane, the ester or salt thereof. The invention to the corresponding lubricant composition, to the lubricant layer produced thereof and to its use.

Abstract: The present invention provides a lubricant composition for hot metal working which is capable of inhibiting generation of flaws on the surface of materials to be provided for hot metal working, and provides a method of hot metal working. The invention provides a lubricant composition for hot metal working comprising a plurality of glass frits respectively having different softening point from each other.

Abstract: Provided herein are compositions comprising at least one estolide compound of formula: in which n is an integer equal to or greater than 0; m is an integer equal to or greater than 1; R1, independently for each occurrence, is selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; R2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R3 and R4, independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched. Also provided are uses of the compositions described herein.

Abstract: The present invention provides a lubricating oil for rolling, which contains a mineral oil and/or a synthetic oil as the main component and has a friction coefficient of 0.2 or more, and a rolling method using the lubricating oil for rolling.

Abstract: The present invention provides a method for supplying lubricant to various kinds of steel sheets with different qualities in cold rolling without any restrictions, such as lubricant supplying apparatus or lubrication conditions. This method comprises storing two or more kinds of lubricant such as A and B, having different compositions, selecting one lubricant or a mixture lubricant of the above A and B in accordance with the friction coefficient between the steel sheet to be cold rolled and a work-rolls, and supplying an emulsion comprising a mixture of the lubricant A and/or B and heated water.

Abstract: Provided is a water-based lubricant comprising a hyperbranch-type polyglycerol having an absolute molecular weight of from 5,000 to 500,000. The water-based lubricant has a small friction coefficient and is excellent in lubrication performance and defoamability, as compared with conventional water-based lubricants comprising an ethylene/propylene oxide copolymer, and is favorable, for example, for a water-based metal processing agent and a hydraulic pressure fluid.

Abstract: A rolling train for rolling a strip has a number of rolling stands and a coiler. The rolling stands have work and backing rolls. Data of the strip are fed to a control device of the rolling train which determines individual pass reductions for the rolling stands based on the data. It controls the main rolling stands and the coiler such that the strip is rolled in the main rolling stands according to the individual pass reductions and then coiled up. It determines the individual pass reductions such that they are zero and controls the rolling stand arranged directly upstream of the coiler such that—with respect to this main rolling stand—the tension in the strip on the outlet side is less than on the inlet side, but the strip runs through this rolling stand without undergoing any forming, at least on one side.

Abstract: A lubricant for hot-rolling tools in which an oxide-based laminar compound such as potassium tetrasilicic mica, sodium tetrasilicic mica, vermiculite, and bentonite, a boric acid compound such as boric acid, potassium borate, and sodium borate, and graphite are dispersed and dissolved in water, and in which the blending proportion of the oxide-based laminar compound to the boric acid compound is, in mass ratio, 10:90 to 70:30, and the content of the graphite is 1.0 to 4.5%. Applying this lubricant on the surface of the mandrel bar at the time of mandrel mill rolling enables a lubricating film to be formed on the surface of the bar and to exert excellent seizure resistance, and also allows the lubricant to be immune from remaining in the inner surface of tube.

Abstract: The invention relates to a process for manufacturing a steel Yankee cylinder (1), where the Yankee cylinder (1) is welded together from individual pre- or finish-machined cylinder sections (8, 9, 10). The invention also relates to a Yankee cylinder (1) that is manufactured using the manufacturing process according to the invention.

Abstract: When performing piercing-rolling by use of a plug with a protection film on its surface, applying a lubricant made of an aqueous solution containing a total of 5 to 30% mass % of one or more of boron oxide, boric acid, and amine borate to the protection film on the plug surface, and using this plug for piercing-rolling makes it possible to realize the increase of the life of plug for piecing-rolling without reducing the efficiency of piercing-rolling. The plug can be cooled after the piecing-rolling, the application of the above described lubricant is performed when the surface temperature of the front edge of plug decreases to 100° C. or less, and the plug is reused for the piercing-rolling. In this occasion, the protection film on the plug . surface can be formed by arc spraying iron wire material onto the surface of the base metal of plug, and comprises oxides and Fe.

Abstract: A process for the wet drawing of a steel wire intended for reinforcing a pneumatic tire. The process starts from a steel wire having a diameter greater than 0.6 mm. The wire is drawn through a series of dies of decreasing diameter, in the presence of a lubricant composition that is in the form of an aqueous dispersion, down to a predetermined final diameter of less than 0.5 mm. The aqueous dispersion comprises solid particles of an ester of a fatty acid comprising from 5 to 40 carbon atoms.

Abstract: A metal forming process involves applying a lubricant, formed from a vitreous enamel mixed with particles of boron nitride, to at least one surface of a sheet metal blank, and without pre-heating the sheet metal blank, placing the sheet metal blank having the lubricant applied to the surface(s) thereof into a pre-heated forming tool so that the at least one surface contacts a surface of the forming tool. The method further involves, via the pre-heated forming tool, forming the sheet metal blank into a desired part shape, and during such forming, forming a lubricant layer on the surface(s) as the lubricant is heated from the pre-heated forming tool, the lubricant layer adhering to the surface(s) of the sheet metal blank.

Abstract: A press forming method for a metal sheet uses dies, a surface roughness of which is an arithmetical mean roughness Ra of 7.5 ?m or smaller, which are used as a punch, an upper die, and a blank holder. Fluid with a kinematic viscosity of 500 mm2/s or lower is supplied to a space between a metal sheet and the blank holder, a space between the metal sheet and the punch, and a space between the metal sheet and the upper die. A die is detached from a workpiece in the middle of forming, and resuming the forming.

Abstract: The disclosure relates to a cold rolling fluid, including: (a) a hydrocarbon base including at least 50 wt % of isoparaffins; (b) one or more frictional modifiers selected from among fatty alcohols, fatty acids, fatty amines, fatty acid esters, or polymer esters resulting from the esterification of alpha-olefin copolymers and dicarboxylic acids using alcohols; and (c) one or more phosphorous anti-wear and/or extreme pressure additives. The disclosure also relates to an emulsion containing the rolling fluid and to the use of the rolling fluid for cold-rolling steel.

Abstract: The invention provides a metal working fluid composition which comprises a morpholine compound and an isothiazoline compound and a metal working method which makes use of the metal working fluid composition. The composition is excellent in antiseptic properties, and can widely be applied to metal working techniques such as cutting, grinding, form rolling, press working and plastic working techniques.

Abstract: To provide a lubricant for metallic material working and a method of press working a metallic material that makes it possible to improve the working accuracy of a press worked product and prolong the life of the die assembly beyond prior levels of life. [Solution] A lubricant for metallic material working comprises a mixture of a sulfur-based extreme pressure agent, an organic zinc compound, a calcium-based additive, and an ester compound, with lubricant base oil. The sulfur-based extreme pressure agent has a sulfur content of 5% by weight or higher based on the total weight of the lubricant. The organic zinc compound has a zinc content of 0.5% by weight or higher based on the total weight of the lubricant. The calcium-based additive has a calcium content of 0.5% by weight or higher based on the total weight of the lubricant. And the ester compound occupies a content of 1.0% by weight or higher based on the total weight of the lubricant.

Abstract: A tube is made by first making a tubular billet with a central cavity by a primary shaping operation. Then the billet is fed to a radial forging machine where it is forged into the tube by decreasing an outer diameter of the billet and a radial thickness of a wall of the billet.

Abstract: A lubricant for hot-rolling tools in which an oxide-based laminar compound such as potassium tetrasilicic mica, sodium tetrasilicic mica, vermiculite, and bentonite, a boric acid compound such as boric acid, potassium borate, and sodium borate, and graphite are dispersed and dissolved in water, and in which the blending proportion of the oxide-based laminar compound to the boric acid compound is, in mass ratio, 10:90 to 70:30, and the content of the graphite is 1.0 to 4.5%. Applying this lubricant on the surface of the mandrel bar at the time of mandrel mill rolling enables a lubricating film to be formed on the surface of the bar and to exert excellent seizure resistance, and also allows the lubricant to be immune from remaining in the inner surface of tube.