JP2006142343A - METHOD FOR MANUFACTURING Mo-ADDED FERRITIC STAINLESS STEEL SHEET EXCELLENT IN ANTIDAZZLE CHARACTERISTIC - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a Mo-added ferritic stainless steel sheet excellent in antidazzle characteristic by which the antidazzle characteristic equivalent to 2B is obtained even by bright annealing. <P>SOLUTION: At cold rolling or skin pass rolling after the bright annealing, by using dull-worked work rolls for a pass before the final and using work rolls which are lower than the dull-worked work rolls in roughness for the final pass, proper antidazzle characteristic is imparted to products by adjusting the surface roughness of the steel sheet before or after the bright annealing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a Mo-added ferritic stainless steel sheet that is excellent in antiglare properties (surface properties that are not dazzling and also have a metallic luster).

  One type of ferritic stainless steel is a Mo-added ferritic stainless steel whose corrosion resistance is enhanced by adding Mo, such as 18 mass% Cr-0.5 mass% Mo. In this steel type, when the steel sheet is manufactured by atmospheric annealing (2B; needs to be pickled after annealing), although an appropriate antiglare property is obtained, the descalability is poor, so the acid unevenness (pickled finish state) In-plane non-uniformity) easily occurs, and it is difficult to obtain uniform surface properties. On the other hand, when manufactured by bright annealing (BA; pickling after annealing is not necessary), it is highly glossy and excessively glossy, so that it is required to have an appropriate antiglare property (for example, an external boiler exterior plate for home use). It cannot be used for interior plates of commercial refrigerators.

As a manufacturing method of a stainless steel plate excellent in antiglare property, a method of rolling using a dull work roll in the final pass of cold rolling (Patent Document 1), or a dull work roll by temper rolling after annealing. A method of using and rolling is known.
JP 63-49305 A

However, the conventional method of rolling using a dull work roll in the final pass of cold rolling or temper rolling after annealing is applied to building materials (roof materials) that do not like reflection of sunlight. This is a manufacturing method, and the metallic luster peculiar to a stainless steel plate is completely lost. Therefore, it cannot be applied to applications that require moderate anti-glare properties.
Then, an object of this invention is to provide the manufacturing method of Mo addition ferritic stainless steel plate excellent in anti-glare property from which anti-glare property equivalent to 2B is obtained even by bright annealing.

  The present invention (1), which has achieved the above object, is the final of cold rolling in order to sequentially perform cold rolling, bright annealing, or further temper rolling on a hot rolled sheet material having a composition equivalent to Mo-added ferritic stainless steel. It is a method for producing a Mo-added ferritic stainless steel sheet having excellent antiglare properties, wherein a dull work roll is used for the front pass and a work roll having a lower roughness than the dull work roll is used for the final pass.

  In the present invention (2), in order to sequentially perform cold rolling, bright annealing, and temper rolling on a hot-rolled sheet material having a composition equivalent to Mo-added ferritic stainless steel, the temper rolling is a two-pass rolling, In the manufacturing method of the Mo addition ferritic stainless steel plate excellent in anti-glare property characterized by using a dull work roll in the first pass and using a work roll having a lower roughness than the dull work roll in the second pass. is there.

  Further, the present invention (3) is the present invention (2), in which the temper rolling is replaced with two-pass rolling or more than three passes, and the dull process is performed in the final previous pass instead of the first pass of the temper rolling. A work roll is used, and instead of the second pass, a work roll having a lower roughness than the dull work roll is used in the final pass.

  According to the present invention, the roughness of the dull work roll used in the last pass before the cold rolling is changed, or the temper roll elongation is increased by using the dull work roll in the first pass of the temper rolling. By changing the rate, the surface roughness of the steel sheet before or after bright annealing is adjusted to control the antiglare property of the final product. Thereby, Mo-added ferritic stainless steel having antiglare property equivalent to 2B even in bright annealing Steel sheets can be manufactured. Therefore, the occurrence of acid unevenness, which is a problem during 2B production, is eliminated, and uniform surface properties can be obtained.

The hot-rolled sheet material has a composition equivalent to Mo-added ferritic stainless steel. Specifically, this composition may be any of the compositions of SUS434, SUS436L, SUS436J1L, SUS444, SUS445J1, SUS445J2, SUS447J1, and SUSXM27 defined in JIS G 4305.
The dulled work roll referred to in the present invention refers to a work roll having a roll surface roughness Ra of 2.0 μm or more. Preferably Ra = 2.5 to 16.0 μm, more preferably Ra = 4.6 to 16.0 μm for cold rolling and Ra = 2.5 to 3.5 μm for temper rolling. The work roll having a lower roughness than the dull work roll may be one used in ordinary cold rolling or temper rolling (so-called bright roll), and the preferred roll surface roughness is Ra = 0. It is 08-0.12 micrometer. These surface roughnesses conform to JIS B601.

In addition, although it does not specifically limit in the path | pass upstream from the path | pass before cold rolling, It is more desirable to use the work roll of low roughness rather than a dull process work roll.
The degree of antiglare property can be evaluated by the specular gloss (for example, Gs (20 °)) defined in JIS Z 8741 and the whiteness (Lab) defined in JIS Z 8715. According to the past results, the surface texture equivalent to 2B corresponds to the range of Gs (20 °) = 750 ± 100 and Lab = 45 ± 2.5. Therefore, in carrying out the present invention, it is preferable to set the roughness or temper rolling elongation of the dulled work roll so that Gs (20 °) and Lab on the product surface fall within the above ranges.

  SUS436J1L equivalent composition (18 mass% Cr-0.5 mass% Mo) hot-rolled sheet coil (No. 1 finish white skin coil; sheet thickness: 4 mm) is used as a raw material under the conditions shown in Table 1 for cold rolling and brightening. Annealing (or atmospheric annealing) or temper rolling was further performed in this order to produce a Mo-added ferritic stainless steel plate (plate thickness 0.5 mm). About the obtained product, the said glossiness (Gs (20 degrees)) and the said whiteness (Lab) were measured. The results are shown in Table 1.

  FIG. 1 is a scatter diagram showing the correspondence between Gs (20 °) on the product surface and Lab for each condition in Table 1. As shown in the figure, in the present invention examples (No. 4, 5, 6), Gs (20 °) and Lab on the product surface are suitable ranges corresponding to the surface properties equivalent to 2B (ranges surrounded by dotted lines) It can be seen that a Mo-added ferritic stainless steel sheet that is within the range and excellent in antiglare properties can be obtained.

  According to the present invention, a Mo-added ferritic stainless steel sheet having excellent antiglare properties can be produced with BA, and the occurrence of acid unevenness that was a problem during 2B production has been eliminated. Therefore, OPY (yield × first grade rate) is Although it was 75.8% at the time of 2B manufacture, it improved markedly to 90.4% after implementation of the present invention.

It is a scatter diagram which shows the correspondence of Gs (20 degrees) of a product surface, and Lab about each condition of Table 1. FIG.

Claims (3)

When cold rolling, bright annealing, or further temper rolling is performed sequentially on a hot-rolled sheet material having a composition equivalent to Mo-added ferritic stainless steel, a dull work roll is used as the final pass before the cold rolling. The manufacturing method of the Mo addition ferritic stainless steel plate excellent in the anti-glare property characterized by using a work roll of low roughness rather than a dull work roll. In order to perform cold rolling, bright annealing, and temper rolling sequentially on hot-rolled sheet material having a composition equivalent to Mo-added ferritic stainless steel, the temper rolling is set to two-pass rolling, and the dull work roll is applied to the first pass. A method for producing a Mo-added ferritic stainless steel sheet having excellent antiglare properties, wherein a work roll having a lower roughness than a dull work roll is used in the second pass. When cold rolling, bright annealing, and temper rolling are sequentially performed on a hot-rolled sheet material having a composition equivalent to Mo-added ferritic stainless steel, the temper rolling is made into three or more passes, and the final pass before the temper rolling. A method for producing a Mo-added ferritic stainless steel sheet having excellent antiglare properties, wherein a dulled work roll is used for the final pass, and a work roll having a lower roughness than the dulled work roll is used for the final pass.