Cold Working Lubricant and Cold Working Method for Steel Pipe
a cold working method and cold working technology, applied in the direction of lubricant composition, manufacturing tools, shaping tools, etc., can solve the problems of inability to adopt chemical treatment methods, all these lubricating treatment methods have problems, and the application of lubricating treatments in the cold working of steel pipes is problematic. , to achieve the effect of easy removal, high load reduction effect and easy formation
Inactive Publication Date: 2010-06-03
SUMITOMO METAL IND LTD
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Benefits of technology
The alkali soap lubricant effectively reduces workload during cold working, forms a durable yet removable layer on steel pipes, preventing damage from residue and simplifying post-processing, thus enhancing the mechanical characteristics and environmental sustainability of the steel products.
Problems solved by technology
However, all these lubricating treatment methods have problems as described below.
Particularly, the application to lubricating treatments in the cold working of a steel pipe is problematic.
The chemical treatment method cannot be adopted except for cold working of a steel wire rod or a steel bar, because it includes many processes for forming a substrate layer and thus requires large-scaled facilities and troublesome works.
In the synthetic resin layer lubricating method, in order to prevent peeling of the synthetic resin layer during cold working, the synthetic resin layer is needed to be firmly adhered to the surface of the metal material, which results in an increased cost caused by an enlarged scale of facilities and a troublesome work.
Therefore, this method would not be adopted except for cold working of a steel sheet.
On the other hand, the oil lubricating method requires neither a troublesome work nor an enlarged scale of facilities, compared with the chemical treatment method and the synthetic resin layer lubricating method.
However, the oil lubricating method does not reduce the working load more than the chemical treatment method or the synthetic resin layer lubricating method.
It results in seizing on this part.
In all theses lubricating treatment methods, it is difficult to remove the lubricant or the lubricating oil from the surface of the metal material after cold working.
The remaining lubricant or lubricating oil may cause various problems in a heat treatment process or the like after the cold working.
When a metal material with a chemical treatment layer consisting of a phosphate remaining on the surface is heat-treated, for example, a phosphorization to the metal material may deteriorate the material strength.
When a metal soap layer containing a non-alkali metal salt of Zn, Mn or the like remains on the surface, the same problem is caused during heat treatment.
Namely, the lubricant remaining on the surface may deteriorate the mechanical characteristics of the surface of the metal product during heat treatment.
Further, since the lubricating oil or synthetic resin layer is regarded as dirt, the product with remaining on the surface cannot be sold thereafter.
Because of this problem, the lubricant layer or lubricating oil formed by the lubricating treatment must be removed after cold working.
This method comprises a liquid lubricant consisting of a mixture of fine lubricant particles such as molybdenum disulfide and graphite with metal soap applied to the working surface of an aluminum plate, prior to press working However, this method aims at press working of a sheet metal such as the aluminum plate with extremely low cold deformation resistance, and is scarcely applicable to the lubricating treatment for cold working of a pipe-shaped metal, which involves harsh plastic deformation in addition to high cold deformation resistance, such as a cold working of steel pipe including pipe expansion work or cold drawing work.
Furthermore, the lubricant disclosed in Patent document 1 is difficult to be removed, and when it is applied to the lubricating treatment during the cold working of a steel pipe, particularly, the fine lubricant particles such as molybdenum disulfide and graphite are scarcely removed from the steel pipe surface.
Because, when the oxide or a hydroxide layer is formed on the surface of the steel pipe, a minute unevenness or crack is apt to occur on the oxide or hydroxide layer, which would trap fine particles of the lubricant such as molybdenum disulfide and graphite cannot be removed.
However, this costly solid lubricant, although used for warm press working of a sheet metal such as an aluminum plate with an extremely low cold deformation resistance, cannot be applied to the lubricating treatment for cold working of a pipe-shaped metal such as pipe expansion work or cold drawing work with a high cold deformation resistance, which requires a harsh plastic deformation.
Method used
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example 1
[0074]A seamless steel pipe was subjected to pipe expansion using Na stearate as a lubricant, and the load applied in the pipe expansion was examined.
[0075]A seamless steel pipe with a shape and a strength (grade) shown in Table 4 (hereinafter simply referred to as steel pipe) was prepared. In the table, the unit of outside diameter, inside diameter, pipe thickness and length are shown by mm, and the grade is based on the API standard. The material of the steel pipe is carbon steel.
TABLE 4ShapeOutsideInside diameterPipe thicknessLengthdiameter (mm)(mm)(mm)(mm)Grade89.0575.336.861505CT3-P110
[0076]Three pipe expansion plugs 1 of a shape shown in FIG. 2 were prepared. A layer of 3 mm thickness was formed respectively on the surface 10 to contact with the inner surface of the steel pipe of each plug 1, using the materials and formation method shown in Table 5.
TABLE 5Plug No.Layer material1Cemented carbide2SKD steel3CrN layer by ion plating
[0077]The plug of Plug No. 1 is a cemented carbi...
example 2
[0089]A pipe end of a stainless steel pipe was expanded using Na stearate and conventional mineral oil as lubricants, respectively, and the load applied in pipe expansion was examined for each lubricant.
[0090]A super-13Cr steel pipe (hereinafter simply referred to as stainless steel pipe) with an outside diameter 114.3 mm, a thickness 8.56 mm and an inside diameter 97.18 mm was prepared as a steel pipe material.
[0091]A plug used for the pipe expansion was made of cemented carbide. This plug has a TD-treated surface and a shape similar to that of FIG. 3. The maximum plug diameter of the plug is 98.15 mm.
[0092]The pipe expansion was carried out according to the following method. Ten stainless steel pipes were prepared, in which the inner surface was at least within the range of 50 mm from the pipe end and was coated with Na stearate aqueous solution of 100 g / L (liter) uniformly, and substantially dried. The Na stearate aqueous solution was prepared within a plastic vessel. In order to...
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Abstract
The present invention provides a lubricant comprising an alkali soap and a cold working method, in which the lubricant layer can be easily formed on the surface of a steel pipe prior to cold working the reduces the work load during cold working of the steel pipe, and whose layer can be easily removed by washing the surface of the steel pipe after cold working. After that, an alkali soap aqueous solution or aqueous pasty alkali soap is applied to the working surface of the steel pipe, cold working of the steel pipe is performed, and thereafter the alkali soap layer is removed by washing with water. The alkali soap aqueous solution or aqueous pasty alkali soap is preferably prepared within a vessel having an inner surface consisting of a non-metal material.
Description
FIELD OF THE INVENTION[0001]The present invention relates to a cold working lubricant and a cold working method for steel pipe. More specifically, the present invention relates to a lubricant excellent in lubricating property during cold working of a steel pipe and excellent in washing removability from the steel pipe surface after cold working, and a cold working method for steel pipe using the same.BACKGROUND OF THE INVENTION[0002]In cold working of a steel pipe, lubricating treatment has been executed for the purpose of reducing a working load and preventing a seizure between the steel pipe and a working tool.[0003]Three methods have been conventionally known for the lubricating treatment in cold working of a metal material including the steel pipe, namely, a chemical treatment method, an oil lubricating method and a synthetic resin layer lubricating method.[0004]The chemical treatment method comprises a chemical treatment process such as pickling for removing an oxide layer or a...
Claims
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IPC IPC(8): B21D37/16
CPCC10M105/24C10M173/02C10M2207/1253C10N2230/06C10N2240/403C10N2250/121C10N2240/405C10N2210/01C10N2030/06C10N2050/02C10N2040/241C10N2040/243C10N2010/02
InventorAKIYAMA, MASAYOSHIARITA, TSUTOMU
OwnerSUMITOMO METAL IND LTD