Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D37/00—Tools as parts of machines covered by this subclass
  • B21D37/18—Lubricating, e.g. lubricating tool and workpiece simultaneously
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C23/00—Extruding metal; Impact extrusion
  • B21C23/32—Lubrication of metal being extruded or of dies, or the like, e.g. physical state of lubricant, location where lubricant is applied
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C9/00—Cooling, heating or lubricating drawing material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C9/00—Cooling, heating or lubricating drawing material
  • B21C9/02—Selection of compositions therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
  • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor

Definitions

• a variety of steel products are manufactured by processes in which a workpiece of the metal, e.g. a rod, tube, sheet or block or the like, is changed in shaped and dimensions, for example by being forced through an extrusion or drawing die to shape it and reduce its thickness, or by being subjected to forming forces such as those imparted in a stamping machine, a press or the like. It is often desired to operate at essentially ambient temperatures without application of substantial external heat to the system. Such operations are commonly referred to as cold-forming operations, and by this term it is intended herein to convey this meeting.
• the economics of the forming processes depend in large part on the extent to which the dimensions of the steel being treated can be reduced in one pass through the forming operation, and upon the amount of force needed to effect a given change. It is obvious that the cost of forming a steel product increases as the number of passes through the forming operation increases, and that the amount of force which must be applied to the workpiece to effect a given change influences the type of equipment which can be used. These economic factors are of prime importance in this competitive field. At the same time, the product must be left with a smooth surface, and attempts to improve process economics by increasing the extent of size or shape change per pass of the workpiece in each forming step often leads to products having marred surfaces, or to production of strains in the metal comprising the workpiece.
• a rcductionin the force, or pressure, required for extrusion is frequently essential to prevent destruction of the die.
• reducing extrusion pressure from 248,000 p.s.i. to 240,000 psi. is an increase in the safety factor of five times, or 10,000 p.s.i. as versus 2000 p.s.i. This is most significant in practical terms.
• a variety of means have been devised for improving the forming processes, both as regards the extent to which the processes change the shape or dimension of the workpiece and the amount of force required to effect these changes, and as regards the surface finish of the formed product.
• These means have included providing improved forming equipment, for example improved die surfaces and designs in extrusion or drawing techniques, and devising coating materials both for the die and the workpiece to be formed.
• These approaches have been fruitful; however, the search has continued for still better forming methods, particularly for better cold-forming methods.
• the barium ferrate coating is a red-to-brown coating, and is provided on the steel workpiece to be formed in a thickness which provides 0.01 to 10, and preferably 0.05 to 2.5, grams of the ferrate per square foot of steel surface. Coatings measuring less than 0.01 gram per square foot are not sufiiciently heavy to provide adequate improvement of coldforming operations, whereas use of more than 10 grams of barium ferrate per square foot in a coating, while useful, is unnecessary and expensive.
• the barium ferrate coating is hard and is resistant to abrasion and the action of solvents and alkalies. The coating also is very smooth, and provides excellent lubrication between the forming die, for example an extruding, drawing or stamping die and the workpiece surface.
• the coating suitably is provided by the method described in copending application Ser. No. 104,780, filed Apr. 24, 1961, now Patent No. 3,206,384 and assigned to the assignee of this application.
• This method involves immersing the ferrous metal as an anode in an alkaline electrolyte solution, containing barium ions, preferably introduced as the barium hydroxide, and passing an electric current through the ferrous metal anode at a potential of at least 1.4 volts in an amount of at least about 2 amperes per square foot of the ferrous metal.
• Any conductor which is resistant to the electrolyte can serve as the cathode.
• the barium ions are preferably introduced as barium hydroxide, and preferably are present at a concentration of about /5 N to the saturated condition.
• the solution also frequently contains an alkali, e.g. sodium hydroxide, to raise its pH.
• the steel workpiece tobe extruded or otherwise formed may be in the form of a rod having a circular or other cross-section, or in the form of a sheet, a tube or the like. Its physical form is dependent upon the forming operation to be applied; for example, drawing and extrusion are normally carried out on billets, rods, tubes or wires, whereas stamping is generally performed on a sheet of the metal.
• the barium ferrate coating of this invention provides for very effective separation of the steel workpiece from the surface of the forming apparatus, and thus improves the overall operation.
• the Forward Extrusions shown in the following examples were carried out by forcing a billet of steel through an extrusion die to form a solid bar of smaller cross-section.
• the forward end of the billet was tapered to conform to the entry angle of the extrusion die, and the nose had the appearance of a truncated right-circular cone, the conical surface extending about /4 inch as measured parallel to the axis of the cylinder, the rear base diameter being 1.480 inches and the forward base diameter being 1 inches.
• the billets were 2 .4; inches long.
• the extrusion die had an inner diameter of 1.167 inches and a 90 degree entry angle.
• the extruded bar size was 1.167 inches in diameter and the billet was extruded until the extruded portion was 2 inches in length.
• FORWARD EXTRUSION 5 A (Type 304-L Stainless)-.. Barium Fcrrate 1 (1 ⁇ gt/ft. 145,. 000 50 to (SS-Slightly less smooth and shiny than Ex. 1 sample.
• the barium icrrate coating was provided by HCl acid cleansing the billet for one minute, imincrsin" the cleaned billets in an aqueous 1 N B34011); electrolyte bath and imposing a voltage of 4.5 volts at 150 amps/ft. for 30 minutes at 0., the billets serving as anodes.
• the barium terrate coating was provided by HCl acid cleansing the billet for one minute, immersing the cleaned billet in an aqueous 1 N trusion provided a cross-sectional size reduction of 40%.
• the punch speed was 6 inches per minute.
• the Backward Extrusions shown in the following examples were carried out by piercing a solid billet with a punch to form a hollow cup.
• the deformed portion of the base of the billet formed the inside surface of the cup.
• the billets treated were 1.480 inches in diameter 1 /4 inches long.
• the leading end of the extrusion punch had a diameter of 1.046 inches and was a spherical segment subtended by an included angle of degrees.
• the finished cup had a diameter of 1.500 inches, a 0.227 inch wall, was 1% inches deep and had a /2 inch thick base. This provided a billet reduction of 50% in the cross-sectional area of the metal in the pierced section.
• the punch speed was 6 inches per minute.
• the barium ferrate When compared with the best commercial coatings, namely the zinc phosphate coating and the oxalate coating, the barium ferrate proved to be at least as effective as other coatings in facilitating effective extrusion.
• the results of the extrusion were even superior in the case of the barium ferrate coating, providing a very substantial reduction in extrusion pressure required for the extrusion, and providing somewhat better surface character in the extruded product.
• Examples 6 through 9 demonstrate the effectiveness of the herein barium ferrate coating in facilitating drawing of a musical wire and a typical stainless steel wire.
• Examples 6 and 7 show that uncoated 316 stainless steel wire could be drawn only through the first of the multiple size reduction dies used in these tests without breaking, whereas the coated 316 wire was drawn through a total of 6 dies and underwent a 75% size reduction overall before the test was stopped.
• Examples 8 and 9 demonstrate that the barium ferrate coated music wire was reduced about 37% in thickness in four passes with much lower drawing loads required per pass than Was uncoated music wire. This is of obvious importance in wire drawing, since the amount of force required per draw substantially afiects the type of wire which can be drawn, and the type of equipment necessary for the drawing.
• Method of cold forming a steel workpiece comprising providing on said workpiece a coating of barium ferrate measuring 0.01 gram to grams per square foot, and cold forming said workpiece carrying said barium ferrate coating.
• Method of extruding a steel workpiece comprising providing on said workpiece a coating of barium ferrate measuring 0.01 gram to 10 grams per square foot, and extruding said workpiece carrying said barium ferrate coating through a die.
• Method of drawing a steel wire comprising providing on said wire a coating of barium ferrate measuring 0.01 gram to 10 grams per square foot and drawing said wire carrying said barium ferrate coating through a die.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Metal Extraction Processes (AREA)
• Lubricants (AREA)

Priority Applications (7)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23526841

Family Applications (1)

Country Status (7)

Citations (3)

• 1964
  • 1964-07-31 US US386736A patent/US3314259A/en not_active Expired - Lifetime
• 1965
  • 1965-07-13 GB GB29554/65A patent/GB1087308A/en not_active Expired
  • 1965-07-26 LU LU49161A patent/LU49161A1/xx unknown
  • 1965-07-27 DE DE19651452267 patent/DE1452267A1/de active Pending
  • 1965-07-28 FR FR26394A patent/FR1442802A/fr not_active Expired
  • 1965-07-30 NL NL6509960A patent/NL6509960A/xx unknown
  • 1965-07-30 BE BE667732A patent/BE667732A/xx unknown

Patent Citations (3)

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