TW201012942A - Alloy - Google Patents

Abstract

An Al alloy suitable for processing into a lithographic sheet, the alloy having a composition in weight% of: Fe 0.16 to 0.40 Si up to 0.25 Cu up to 0.01 Mn up to 0.05 Ti up to 0.015 Mg 0.02 to 0.10 Zn up to 0.06 unspecified other components up to 0.03 each Al balance, wherein the minimum Al content is 99.3.

Description

201012942 VI. Description of the Invention: The present invention relates to an alloy suitable for processing into a lithographic sheet, in particular in the form of a thin rolled aluminum strip for use in an offset printing plate maker. An alloy and a method of processing such a lithographic sheet. It is known that lithographic platesetters use an aluminum alloy in the form of a thin rolled aluminum strip. To process a thin rolled aluminum strip into a lithographic sheet, the platesetter will initially degrease or etch the strip typically in an alkaline solution. Aluminum belt. This process prepares the surface of the aluminum for the grain and flattens the minor surface defects. An electric grinder is then performed to form a surface topography having a convoluted hemispherical pit. This process is typically carried out in a hydrochloric acid based electrolyte or in a nitric acid based electrolyte. The electro-grinding plate is made using an alternating current (AC) through an electrolytic cell containing a tape. The electrochemical reaction performed every half cycle effectively removes aluminum from the surface by dissolution. Alternatively, the surface of the aluminum strip can be roughened mechanically (e.g., by wiping). However, this method is not common. The function of the pit formed in the surface of the aluminum strip is to increase the surface area of the aluminum strip and retain the water. In other words, the aluminum strip becomes hydrophilic due to the presence of pits. A decontamination step can then be performed to remove the aluminum hydroxide stains produced during the electrogrind process. The aluminum strip is then anodized. This causes the porous anodic oxide 201012942 to grow on the pit surface of aluminum. This provides an abrasion resistant coating that enhances the durability of the print quality of the lithographic sheet formed from the aluminum strip. It also allows the photosensitive coating to adhere better and makes the sheet more chemically inert, thereby improving its storage time limit. The photosensitive polymeric coating is then typically applied to an aluminum strip. This coating rejects water but attracts oil. Since the printing ink is an oil-based ink, a lithographic printing sheet is required to attract oil.

At this stage, the lithographic printing plate comprises a hydrophilic aqueous anodized aluminum layer covered by a lipophilic photosensitive layer. - in its simplest form, by removing a portion of the coating, such as "forming an image by exposure. * 匕 means that the coating must be easily removed to expose the underlying: hydrophilic anodized layer. However, The layer must also be resistant to wear to maintain a well-defined image during printing. Therefore, it is important that the aluminum tape used to form the lithographic sheet has sufficient strength and proper surface functionality. ) is used to describe the ability of the 枓 to be properly electro-grinded to provide a uniform distribution of pit sizes without the formation of two illusions or directionalities. This s is important in the σσ quality of the resulting printed image. The oxime plate making machine makes the solution based on the heart-beaten α as the electrolyte of the electro-grinding plate. However, it is also known that the mechanism by which the electrolysis process based on ην〇3 is performed differs between the respective electrolytes. It is advantageous for the material tongue to be suitably electropolished in both electrolytes. In the lithographic platemaking industry, it is especially known to use two types of alloys 5 201012942. The first alloy type is called AAl 050 and has the composition shown in Table 1 below. AA1 050 exhibits good electro-grinding characteristics.

If the material has "good electro-grinding characteristics", it means that the material has the ability to produce a uniform pitted surface under various conditions. This material is capable of electrospinning in an electrolyte based on hydrochloric acid or nitric acid. AA1050/AA1050A

Alloy Fe% Si% Cu% Μη% Mg% - Zn% Ti% V% Other 〇/〇A1% AA1050 Up to 0.40 at most 0.25 at most 0.05 at most 0.05 at most 0.05 at most 0.05 at most 0.03 at least 0.05 at 0.03 0.03 at a minimum 99.50 ~993Γ~ min ----- AA1050A up to 0.40 up to 0.25 up to 0.05 up to 0.05 up to 0.05 up to 0.07 up to 0.05 not determined-----J Table 1 The second alloy type is called AA3XXX and contains the composition as set forth in Tables 2 and 3 below. AA3103 or AA3003 alloy. AA3XXX has improved strength when compared to the strength of AA1050. However, the electro-grinding properties of AA3XXX are not as good as those of the AA1050 alloy type. AA3103 ginseng alloy Fe% Si% Cu% Μη% Mg% Zn% Zr + Ti% Cr% Other % A1% AA3103 Up to 0.7 up to 0.50 up to 0.10 0.9 -1.5 up to 0.30 up to 0.20 up to 0.10 up to 0.10 each up to 0.05, total up to 0.15 The remaining scale 2 AA3003 6 201012942 Alloy Fe% Si% Cu% Μη% Mg% Zn% Ti% Other A1 ΑΑ3003 Up to 0.7 to 0.6 0.05-0.20 1.0-1.5 Undetermined up to 0.10 Not up to 0.05% each, total 0.15% Remaining Scene 3 The European, Asian and South American markets traditionally use the AA1050 alloy type. This alloy type is suitably electrospun in a solution based on HC1 and HN〇3 but has a lower strength than other alloys. This is considered a potential problem in the case where an alloy is to be used to form a lithographic sheet for a longer time printing operation. North America traditionally uses the AA3XXX alloy type. It is more difficult to electrogrind this alloy type and therefore this alloy type is more commonly used when mechanical roughening methods are possible. The AA3 XXX alloy can be electropolished in HC1, but the electrosurgical process may produce surface streaking. Therefore, these alloys have relatively poor electrostable properties' but have high initial strength and high baking strength. The abrasion resistance of the photosensitive coating is usually improved by baking a lithographic printing plate. However, this process may have an adverse effect on the strength of the aluminum substrate. This practice is more common in North America and is easier to explain the increased use of A3XXX. The baking strength of the alloy is typically measured using a standard baking test. The standard baking test consisted of heating the alloy for 10 minutes at 24 Torr. It is important that the alloy to be used for processing into a lithographic sheet does not become significantly soft when baked, so that the strength of the alloy is not adversely affected. Significant softening of the aluminum alloy substrate and associated microstructure changes can also have a negative impact on the dimensional properties of the printed board. This may be harmful if it is caused by fatigue. As a general rule, σ has found that alloys exhibiting good electro-grinding properties may not have the required strength and plate properties of 201012942. While an alloy having the desired strength may have poor electrical grinding, in accordance with a first aspect of the present invention, an aluminum alloy is provided which has a printed sheet having a composition suitable for processing into a lithographic form in weight percent:

Fe is 〇·16 to 0.40,

Si is at most 0.25,

Cu is at most 〇.〇1, Μη is at most 〇.〇5,

Ti is at most 0.015,

Mg is 〇.〇2 to 〇.1〇,

Zn is at most 〇.〇6, other components not illustrated are at most 〇3, and the rest are A1', wherein the lowest A1 content is 99.3. By having a high percentage of aluminum in the alloy, the content of the other components is correspondingly lower. This allows the alloy to be more versatile when recycled after use. Preferably, the minimum aluminum content is 99.45 wt. /. . More preferably, the minimum aluminum content is 99.50 wt%. By having a higher weight percentage of aluminum in the alloy, the versatility of the alloy is further improved upon recycling after use. Locks are used to improve the graining efficiency of the alloy, but have a limited effect on the strength of the alloy. However, magnesium improves the mechanical properties (such as strength) of the original alloy and the baked alloy and therefore its presence in the alloy is important. However, limiting the scope of the town to 0.10 wt% does not impair the combination for recycling purposes. 201012942 The versatility of the gold is important. The alloy according to the invention may contain up to 99 〇 〇 / 〇 magnesium. Preferably, the magnesium content is in the range of 0.02 wt〇/〇 to 0.05 wt%. The words also improve the grinding performance of the alloy and have a limited effect on the strength of the alloy. The inventors have discovered that up to 5 weight percent zinc in an aluminum alloy can have a beneficial effect on the electrochemical properties of the alloy. Advantageously, the minimum zinc content is 〇 〇 2 wt 〇 /0. The ratio of zinc to town in the alloy can be substantially in the range of 〇丨 to 23. It has been found that by controlling the zinc and magnesium contents, it is possible to impart good electrogrind properties to the resulting aluminum alloy. Iron is present in the aluminum alloy for two purposes. The first objective is to ensure the formation of iron-rich intermetallics, which is necessary to develop a uniform pit structure during the electrogrinding (roughening) step of the plate making process. The second purpose is to ensure that sufficient iron is present in the solid solution in the material, which is advantageous for good temperature stability properties and especially for strength retention after baking. An advantage of the alloy having the lowest iron content is that it ensures that a sufficient amount of the second phase intermetallic is present in the alloy structure. However, it is advantageous to increase the iron content of the alloy only when the solubility of iron in the aluminum is exceeded, since iron provides a hardening effect in the aluminum alloy, thereby increasing the strength of the alloy. However, increasing the iron to an upper limit of more than wt4 wt% is not advantageous because the further addition does not provide a further positive effect on the alloy structure and only minimally increases the strength. Another disadvantage of increasing the iron content to more than 〇 4 wt% is that it impairs the versatility of the alloy for recycling purposes. 201012942 It has been found that the presence of copper in the aluminum alloy affects the roughened pit morphology, but on the other hand it improves the material strength under the original and baking conditions. The present inventors have found that if the weight percentage of copper is kept below 〇〇1 or 〇1, the alloy may benefit from the improvement in strength due to the presence of copper, and the adverse effect of copper on the pit morphology is kept to a minimum. The presence of titanium in the alloy is necessary to ensure adequate metallurgical grain size control. However, too much titanium can have an adverse effect on the electrochemical performance of the alloy. The present inventors have found that if the weight percentage of titanium does not exceed 0 〇 15, the alloy can benefit from the grain size control achieved by free titanium, but at the same time the adverse effect on the electrochemical performance is kept to a minimum. The alloy according to the invention may contain up to 0.049 wt% manganese. Preferably, the minimum cerium content is 0.005 wt%. The presence of alloys is used to increase the original and toasting strength of the alloy. However, the shortness can have a negative effect on the electro-grinding properties of the alloy and therefore the explosive content in the alloy should not be too high. Preferably, the turing content is in the range of 0.005 wt% to 0,030 wt%. Advantageously, the ratio of manganese to magnesium is substantially in the range of 〇.〇8 to 163. According to a second aspect of the present invention, a lithographic printing sheet formed of an alloy according to the first aspect of the present invention is provided. The second aspect 'k according to the present invention is for a method of processing a lithographic sheet formed of an alloy according to the first aspect of the present invention. The invention will now be described, by way of example only, with reference to the embodiments set forth below. The details of the composition of the four embodiments of the preferred embodiment of the present invention, 201012942, which show the weight percent of the components forming the alloy, are set forth below. Alloy A1 Fe Si Cu Μη Ti Mg Zn Other Example 1 99.48 0.36 0.08 0.001 0.009 0.006 0.046 0.022 0.005 Example 2 99.44 Γθ.33 0.05 0.001 0.049 0.008 0.048 0.060 0.008 Example 3 99.39 0.35 0.06 0.001 0.049 0.009 0.080 0.053 0.007 Example 4 99.52 h0.33 0.06 0.001 0.009 0.008 0.045 0.022 0.007 Table 4 The present invention will be further described by way of non-limiting example only with reference to the accompanying drawings, in which: Figure 1 is a graphical representation showing The alloy groups AA3 XXX and AA1050 are compared in the original, unbaked state and after baking for 1 minute at each of 2 ° ° C, 220 ° C, 240 ° C and 260 ° C. The ultimate tensile strength in the longitudinal direction of Examples 1, 2, 3 and 4 identified above. Figure 2 is a graphical representation showing the original, unbaked state and at 200 ° C, 220 ° C, 240 compared to the known alloy set aa 1050. (: and the test stress (Rp) in the longitudinal direction of the above-identified Examples #1, 2, 3, and 4 after baking for 1 minute and 260 C. Figure 3 is a graphical representation, The display is compared to the known alloy group aa 1050' in the original, unbaked state and after baking at 200 ° C, 220 ° C, 24 (one of TC and 260 C for 1 minute, The ultimate tensile strength in the transverse direction of Examples 1, 2, 3 and 4 identified above. Figure 4 is a graphical representation showing the original, unbaked state compared to the known alloy set aa 1050. After and after baking at 20 (TC, 220 ° C, 24 CTC and 260 C for 1 〇 minutes, the above-identified Example 11 201012942 and 4 lateral direction and 5a are the alloys of each alloy 5a Micrograph of the cross section of the sample. Magnification is X 100. Test stress (Rp) on the test. AA1050 after undergoing the bending test, the magnification of Figure 5 is x200 and Figures 6 and 6a are the samples of the respective application examples 1. The cross section of Fig. 6a is a micrograph showing the solid surface of the above-mentioned time after the bending test. The magnification of Fig. 6 is χ2〇〇X. 100 〇 Figure 7 shows the map s

A micrograph of a more detailed external f-curved surface of the sample of 1050; and the magnification is χΐΐ25. Fig. 8 is a micrograph showing a more detailed outer curved surface of the sample of Example 1 shown in Fig. 6. The magnification of 08 is χη25 with fine external tensile strength or ultimate tensile strength/stress "ui sakitensile

Strength/stress, UTS) is the most significant load applied to the material during the tensile test divided by the original cross-sectional area of the material. Consistent in brittleness or Le == crack point, but usually after declining stress after uts has been exceeded

The test stress (pr〇〇fStress, Rp) is the stress required to produce a quantitative permanent lift "plastic deformation" in a metal that does not exhibit different yields. In Figures 2 and 4, the test stress is 〇 2%. Strain (Rp stress. P) As stated above, the standard baking test is at 24 〇t: T 1 〇 minutes. In Figures 1 to 4, other temperatures are also tested (ie 2 〇. Knife. At I, 220 (: And 26〇. In order to show the strength characteristics of each alloy and how it is low under different baking conditions. Can be lowered 12 201012942 As shown in Figure 1, when compared with AA1050 combination gold, in the original unbaked state And at the discrimination temperature, each of Examples 1 to 4 has a higher ultimate tensile strength in the longitudinal direction. However, the ΑΑ3 χχχ group alloy has a higher strength than Examples 1 to 4. Fig. 2 Each of Examples i to 4 had a higher test stress in the longitudinal direction than the ΑΑ1050 combination gold in the original unbaked state and at the discrimination temperature.

Figure 3 shows the example in the original unbaked state and at the specified temperature compared to the ΑΑι〇50 combination gold! Each of the four has a relatively extreme tensile strength in the lateral direction. Fig. 4 shows that, in the original state and at the specified temperature, each of the examples i to 4 has a comparative test force in the lateral direction as compared with the AA1050 combination gold. In terms of pressure performance, it is found that the bending property is more important than the strength but not easy to measure. Because of A, the intensity is usually used as a general guideline. However, simple bending tests have been performed on subsequent embodiments. The bending test used was based on the static test of manufacturing and testing the bending used to secure the lithographic printing plate to the printing press. Static testing is considered to be most suitable because the nature of the material (eg, human gold: methods of forming, tempering, and processing alloys) has a significant effect on the initial f-curve; it is determined by the bend size and material specifications. The failure caused by labor is mainly due to the bending test, which makes the group of strict parameters formed by a specific alloy. If the size differs from the specified value (including to the current grid), 13 201012942 this may damage the test results. Keep the thickness of the sample as constant as possible, between 〇 275 mm and 〇 280 mm. The inner bending radius and size primarily determine the amount of strain on the surface outside the bend. This can be significantly different with only small changes in the set parameters. Therefore, the inner bending radius is kept constant. When in use, the aluminum lithographic printing plate will be bent using a bending machine. The plate bender is associated with the printing press and is part of the means for forming the bend. In this test, 6 turns were formed around the set radius. Simple bending to simulate a curved plate. 60° is within the range of the bending angles typically used. The test was carried out in two directions, wherein the bending axis was parallel to and perpendicular to the rolling direction of the sheet > the rolling direction was the direction in which the aluminum sheet was machined during rolling. These tests were compared to tests conducted on AA1050 combination gold. After the test, the bending of the cross section and the outer surface of the alloy was evaluated using optical microscopy. A micrograph showing the bending test data of the sample of AA1〇5〇 alloy and the sample of Example t identified above is shown in Figs. 5 to 8. ❹ Figures 5 and 5a are micrographs showing cross sections of samples of the AA1050 alloy after undergoing a bending test as described above. It can be seen from this figure that there is an inward distortion on the inner surface of the alloy caused by the compressive deformation of the inner curved surface. This distortion is in the annular region identified by the component symbol 胄i. The compression deformation can be measured by the degree of inward distortion. As shown in the area 2, it is also seen that a ridge is formed on the outer surface of the alloy due to shear deformation on the outer surface. The shear deformation can be determined by the depth of the ridge. The letter does not form the deformation of the ridge as a material advantage. This is because it is believed that the ridge can act as a stress concentrator and act as a weakness that causes the printing plate to fail. Figures 6 and 6a show cross sections of the sample of Example 1 identified above after undergoing a similar bending test. As can be seen from this figure, the inner bending deformation is shown in the region 3, and when compared with the outer surface of the sample of the AA1050 alloy shown in Figs. 5 and 5a, the outer surface is smoother as shown in the region 4. Figures 7 and 8 show the outer curved surface of the sample of the AA1〇5〇 alloy and the sample of Example 1 in more detail, respectively. Again, as seen in Figure 7, in the annular region marked with the symbol 5, the bead ridge is present in the sample of the AA1050 alloy when compared to the sample of Example 。. The analysis of the micrographs such as those shown in Figures 5 to 8 is primarily qualitative. However, the degree of shear deformation and cracking observed varies from material to material, making it easier to compare between different alloys. Roughness measurements were also made on the curved outer surface of each alloy, and the maximum peak-to-valley distance of the shear-deformed ridge on the outer surface of the bend was measured. These topographical measurements of the externally curved surface were performed using a white light interferometer. In the present application, an interference measurement method is used as a non-contact method for measuring surface roughness. The results of the roughness measurement are illustrated in Table 5 below.

15 201012942 Table 5 The summary of the test results is set out in Table 6 below. As can be seen from the table, the AA1050 combination gold showed moderate deformation during the bending test. It should be understood that the AA3XXX combination gold shows minimal distortion when bent. Level Deformation Degree Variant + A small amount of deformation. Example 1, Example 2 +- Small to medium amount of deformation. Example 3, Example 4 - Moderate deformation. AA1050 As explained above, it is important to obtain a uniformly cratered and streak free surface by electro-grinding the alloy in a hydrochloric acid-based solution or a nitric acid-based solution to produce a surface having good functionality. The electro-grinding performance of Examples 1 to 4 is reported below in comparison with the AA1050 and AA3XXX combination gold. The results described below are based on laboratory testing of the alloy in an HCl-based electrolyte. Use the following scale to measure the performance of the electro-grinding plate. Grade Electric Grinding Edition Notes ++ Excellent This is the target electro-grinding version with high uniformity and easy start. + Good This is an industry-recognized benchmark for electro-grinding performance. +- Appropriate This indicates that the uniformity is slightly degraded, but is still considered acceptable. - Bad This indicates that the uniformity and start-up are significantly degraded. This will indicate a problem at the industrial scale. ~ Very poor This indicates poor performance because an incomplete electro-grinding version is seen at the laboratory scale. Table 7 16 201012942 The results of the different examples are given below. The charge density of 1000 C/dm2 was used for all conditions, but the electro-grinding plate was used for different lengths of time. The "easy" laboratory conditions were achieved by electro-grinding for 24 seconds. 'Achieve "medium" condition by electric grinder version 9.5 seconds. The "difficult" condition was achieved by electro-grinding 6.5 seconds. Alloys are easy to electrogrind conditions. Medium electric mill conditions are difficult. Electric grinder conditions AA1050 ++ + + AA3xxx - - - Example 1 - H- + Example 2 - H-++ Example 3 ++ Example 4 +4 - ++ + Table 8 The results show that each of Examples 1 to 4 has an electrogrinding property that is at least as good as the AA1050 combination gold and is superior to the AA1050 combination gold under certain conditions. 〇 In all cases, each of Examples 1 to 4 had better electrogrind characteristics than the AA3XXX alloy group. Accordingly, the present invention provides a smelting alloy having improved strength compared to the AA1050 alloy type and having improved electrogrind characteristics compared to the AA3XXX alloy type. A method of forming a lithographic sheet according to the present invention will now be briefly described. The method can be viewed as three sub-methods; making alloys and slab casting; making thin rolled aluminum strips; and making lithographic sheets. This method, such as 17 201012942, will now be described in more detail. IL alloy and slab _诰 Rolled sheet ingots are produced by direct casting of molten aluminum by direct chill (DC). The elemental composition of the metal is controlled to the extent by appropriate addition. The thickness of the ingots is typically between 400 and 650 mm. Fuyi thin rolled aluminum crucibles are subjected to scraping of rolled sheet ingots to improve surface finish and uniformity by removing the cast skin. A total of up to 25 claws were removed from both surfaces. 15 Preheat to achieve 400-600. (: The outlet metal temperature is used for hot rolling. The ingot is hot rolled to a plate size between n_18 mm thick. In-line quenching reduces the plate temperature to below 5 (TC. ' Cold rolled to medium size.

Annealing between batches can be performed. The target metal temperature is between 350 and 55 (TC. Use a further cold rolling step to achieve a maximum thickness of between -1 and 0.5 mm. The thickness of the final product can then be flattened and degreased, followed by For the production of lithographic printing sheets. JL lithographic printing enamel is prepared for roughening by means of an alkaline-based engraving method. Μ is preferably achieved by electro-grinding. This is in hydrochloric acid-based electricity or It is carried out in an acid-based electrolyte. AC current is applied to the electric mill plate to achieve roughening. The surface of the electrogrind plate is anodized to improve wear resistance. Various other in-line treatments can be applied to The board properties are improved between some or each of the alkaline processing steps. • A photosensitive coating is applied. After the panel is imaged, it can be baked to improve the abrasion resistance of the photosensitive coating.

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Claims (1)

201012942 VII. Patent application scope: The alloy is processed into a lithographic printing sheet, and the alloy has the following weight %: Fe is 〇'16 to 〇4〇, Si is at most 0.25, Cu is Up to 0.01, Μη is at most, Ti is at most 〇.〇15, Mg is 〇.〇2 to 〇1 〇Zn is at most 0.06, The other components not specified are at most 〇〇3 and the rest are 八1, of which the lowest A1 content is 2. The alloy content of the first item of Shenqing Patent Range is 99.45 wt%. 99_3. , wherein the minimum aluminum (A1) 3. The content of the patented scope is 99.50 wt%. The alloy of item 1 or item 2, wherein the lowest 4. The range of 0.099 wt% magnesium in the scope of the aforementioned patent application. Any alloy containing at most 5. The alloy of any one of the claims, wherein the magnesium content is preferably in the range of from 〇.G2wt% to 0.05 wt%. The alloy of any one of the patent applications of the month, the minimum zinc (Zn) content in the crucible is 0.02 wt%. 7. An alloy having a ratio of any one of the preceding claims to the lock substantially in the range of 0.1 to 2.3, wherein the alloy is within the range of the alloy. In the case of the alloy of any of the patent applications, it contains up to 0.049 wt% of the time. 9. An alloy according to any one of the claims, wherein the minimum manganese (Mn) content is 0.005 wt%. An alloy according to any one of the claims, wherein the manganese (Mn) content is in the range of 0.005 wt% to 〇3〇 wt%. 11. An alloy according to any one of the claims, wherein the ratio of manganese to magnesium is substantially in the range of from 0.08 to 1.63. A lithographic printing sheet' formed by an alloy according to any one of the preceding claims. The 13' method is used to process a lithographic sheet as in claim 12 of the patent application. - 14. An alloy substantially as hereinbefore described with reference to the accompanying drawings. 5. A lithographic printing sheet' which is substantially as hereinbefore described with reference to the accompanying drawings. Reference is made to the method, which is substantially as described above with reference to the accompanying drawings. Eight, the pattern: (such as the next page) 21