JP3592656B2 - Post-processing system in galvanizing - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a post-treatment system in zinc plating capable of performing zinc plating, baking treatment, and hexavalent chromium film treatment.
[0002]
[Prior art]
Zinc plating is widely used as an inexpensive and highly reliable surface treatment. Further, by applying hexavalent chromium film treatment on zinc plating, the appearance can be improved and the corrosion resistance can be significantly increased. Further, hydrogen gas generated during plating and confined in the plating layer is treated by baking, but such matters are treated as points to be improved until recently. It can be seen in the invention of Japanese Patent No. 131764 and JP-A-5-78859.
[0003]
On the other hand, the problem of environmental pollution has become apparent, and the movement to eliminate hexavalent chromium contained in the rust preventive film applied on the galvanized coating has been clarified, and an alternative treatment technology for chromate has been developed. Rust-preventive coatings that do not contain hexavalent chromium include those using trivalent chromium, phosphorus / molybdate coatings, silane coatings, titanium coatings, etc. The problem remains in that it is difficult to change to 100% and it is impossible to find a technology that can be replaced by 100%.
[0004]
However, hexavalent chromium-free has not been fully implemented immediately, but has been partially implemented since 2003. When both hexavalent and trivalent chromate solutions coexist, there is no problem that the trivalent chromate solution enters the hexavalent chromate solution, but conversely, the hexavalent chromate solution cannot enter the trivalent chromate solution. . Therefore, there is a problem in adding a trivalent chromate treatment step to the current hexavalent chromate treatment line, and it is necessary to form a separate line for hexavalent chromate treatment and trivalent chromate treatment.
[0005]
[Problems to be solved by the invention]
The present invention has been made by paying attention to the above points, and its object is to perform four steps generated from the presence or absence of a baking treatment and a baking treatment pass, a hexavalent chromium film treatment, and a hexavalent chromium-free film treatment as one. The point is that it can be performed selectively on the line.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a zinc plating process, a process A for performing zinc plating and a process accompanying the zinc plating process, a process B for performing a baking process on the work that has passed through the zinc plating process A, and a zinc plating process. A process C for performing a hexavalent chromium film treatment on the work that has passed through A, and a process D for performing a hexavalent chromium-free film treatment on the work that has passed through the zinc plating step A. , Step A and Step B and Step D are communicated by the transport means E,
1) Baking treatment step B and hexavalent chromium film treatment step C,
2) Baking treatment step B and hexavalent chromium-free coating treatment step D,
3) Baking treatment process B pass, hexavalent chromium film treatment process C,
4) Baking process B pass, hexavalent chromium-free coating process D,
The following four types of post-processing can be executed.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The post-treatment system according to the present invention is applied to galvanization capable of performing zinc plating, baking treatment, and hexavalent chromium film treatment. Zinc plating can be defined as depositing zinc mainly on the surface of iron or steel, but the zinc plating step A includes pretreatments such as alkali degreasing, pickling, and washing with water, and washing with water is also performed after plating. This is usually done.
[0008]
In the zinc plating step A, the hydrogen gas generated during plating remains in the plating layer without being escaped, and therefore, in many cases, baking treatment is performed to remove the hydrogen gas. For this purpose, a baking step B is provided in parallel with the galvanizing step. However, the baking step B may not be performed.
[0009]
The hexavalent chromium film processing step C is a step of performing hexavalent chromium film processing on the zinc-plated work through the zinc plating step A. The work has been galvanized, and a chromate film is formed thereon using a chromate compound or the like. Hexavalent chromium in the coating is soluble, and even if the coating is destroyed, hexavalent chromium reacts with zinc to produce a chromate coating again, thus exhibiting a reparing property, and therefore cannot be compensated for by other alternative treatments. The point is as mentioned above. However, it is a common recognition that the strong oxidizing power of hexavalent chromium causes various harms to the human body, and a hexavalent chromium-free film treatment has been proposed as an alternative treatment.
[0010]
That is, in the hexavalent chromium-free film processing step D, a film forming process without using hexavalent chromium is performed. Applicable hexavalent chromium-free coating treatments include treatment using trivalent chromium (including chromium only and those added with silicic acid, etc.), phosphorus / molybdate coating, silane coating, titanium coating, etc. Has already been mentioned. In the present invention, these hexavalent chromium-free film treatments can be applied.
[0011]
The zinc plating step A, the baking treatment step B, and the hexavalent chromium coating treatment step C are communicated by the conveying means E, so that a situation in which the workpiece can be sequentially conveyed is prepared. Therefore, the above-described steps A, B, C and D are arranged in a predetermined arrangement so that the route and distance of the conveying means E are not complicated and long.
[0012]
The following four types of steps can be performed by such a processing apparatus as a whole.
1) Baking treatment step B and hexavalent chromium film treatment step C,
2) Baking treatment step B and hexavalent chromium-free coating treatment step D,
3) Baking treatment process B pass, hexavalent chromium film treatment process C,
4) Baking treatment process B pass, hexavalent chromium-free film treatment process D.
In the above, the baking process step B pass means not passing (passing) the baking process step B.
[0013]
The conveying means E communicates with the galvanizing step A, the baking step B, and the hexavalent chromium-free coating step D. The hexavalent chromium film processing step C is arranged at a position deviated from the transporting means E, so that the work that has gone through the galvanizing step A and the baking processing step B is not brought directly through the transporting means E. It is set.
[0014]
【Example】
Hereinafter, the present invention will be described in more detail with reference to the illustrated embodiments. FIG. 1 shows an entire apparatus for performing a zinc plating process using a barrel and a post-processing process according to the present invention, and includes a zinc plating process A, a baking process B, and a hexavalent chromium coating process. C, a transporting means E which communicates a hexavalent chromium-free coating treatment step D, a zinc plating step A, a baking step B, and a hexavalent chromium-free treatment step D.
[0015]
The galvanizing step A has a circling line indicated by A-A ', and the starting end and the ending are extremely close to the conveying means E so that the work can be transferred. The zinc plating step A includes process elements such as alkali degreasing 11, pickling 12, acid electrolysis 13, electrolytic degreasing 14, activation 15, galvanizing 16, and the like. Provided.
[0016]
The baking process step B has a line indicated by BB ', which is arranged in parallel with the zinc plating step AA' of the elongated circuit line. The baking process B is disposed very close to the transporting means E so that the work can be delivered at the start end. The baking treatment step B includes a dehydrator 21, a barrel stacker 22, a baking furnace 23, and a necessary rinsing section 24. At the rear end, the barrel-containing work transfer means e1, which is referred to as "separation", is next to the baking furnace B1. Contact the next line. The transfer means e1 for barrel-containing work includes lifters 25 and 26 (elevators) provided on each line, and a transport section 27 for connecting both lifters.
[0017]
A hexavalent chromium-free coating processing step D is provided on the line following the baking processing step B. By arranging the hexavalent chromium-free film treatment step D before the hexavalent chromium film treatment step C, the hexavalent chromate liquid is not mixed into the trivalent chromate liquid. This connecting line is provided with the above-mentioned barrel so that the hexavalent chromium-free film processing step D can be directly connected to the zinc plating step A through the conveying means E and can be connected to the baking step B from the terminal side. It is connected to the work transfer means e1.
[0018]
The hexavalent chromium-free coating treatment process D is divided into a treatment line indicated by DD 'and a pickling line indicated by D'-D ". It includes a process element such as 31, a rinse 32, a hexavalent chromium-free film treatment 33, and a necessary washing section 34. Further, the pickling line is provided with a cooling section 35, an acid washing 36 with nitric acid or the like, and a necessary washing section 37. Further, transfer means e2, e3, and e4 for transferring the work containing the barrel and moving the barrel are provided at a total of three places before and after the processing line and at the beginning of the hexavalent chromium-free film processing step D, respectively. In each of the lines A, B, C, D, and G, the workpiece is moved by the transfer means provided in each line.
[0019]
The transfer means e3 is provided for transferring the work that has undergone the hexavalent chromium-free film processing step D to the drying step G after the hexavalent chromium-free film processing 33. The drying step G includes a dehydrator 41, and further includes a finished product unloader 42 and an empty can return unit 43. As the transfer means e2, for example, a conveyor for returning a car between the lines G and D is appropriate. These transfer units e1, e2, e3, and e4 may be treated as having the same purpose as the transfer unit E in that they have a purpose of carrying a work. Therefore, conveyors and the like are used for the transporting means and the transporting means, and various types are adopted according to the installation location and the difference in the form of transporting and transporting.
[0020]
The line of the hexavalent chromium film processing step C is provided in parallel outside the line of the hexavalent chromium-free film processing step D. The hexavalent chromium film processing step C has a processing line indicated by CC ′. The work is in communication with the front line (D) by the transfer means e4, and is a hexavalent chromium film processing section comprising rinsing, washing, black, rinsing, washing, green, washing, washing, yellow, washing, washing, white, etc. 51, a dehydrator 52, and a finished product unloader 53 and an empty can return unit 54.
[0021]
In the present invention having such an apparatus configuration, four types of presence / absence of a baking step and presence / absence of a hexavalent chromium film treatment step will be described for each case. In the galvanizing step A, the work that has been subjected to the pretreatment and the galvanizing step is replaced with a basket for processing at the intersection of the A-E line.
[0022]
1) In the case of the baking treatment step B and the hexavalent chromium film treatment C, the work is transported from the intersection of the A-E line to the intersection of the BE line, and is carried by the treatment basket and the carrier. It goes through the steps of stacking, continuous baking with a continuous baking furnace, and step-off. The transfer means e1 is cooled while moving toward the end D 'from the end of the D "line and undergoes water washing, nitric acid washing and water washing. (The empty basket is returned to the intersection of the D-E line by a trolley.) It is transported to the intersection of C-e4 by the trolley of e4, and hexavalent chromium film processing is performed in the hexavalent chromium film processing step C and processed. After the work is completed in the container by the reversing machine of the line C-C ', the empty basket is returned to the line e4 and stands by at the process D side.
[0023]
2) In the case of the baking treatment step B and the hexavalent chromium-free film treatment step D, the workpiece is transported from the intersection of the A-E line to the intersection of the BE line, and the continuous baking furnace is used in the same manner as in the above 1). After baking, it further moves through the transfer means e1 while cooling from the end of D ″ toward D ′, and after being washed with water, nitric acid, and water, undergoes a hexavalent chromium-free film treatment. The work is placed on the processing basket at the intersection of the transfer means e3 and the line D, and is conveyed to the Ge-e3 intersection by the transfer means e3. End the process.
[0024]
3) In the case of the baking treatment process B pass and the hexavalent chromium film treatment process C, the work is moved to the intersection of the DE line by the transport means E, carried by the carrier together with the treatment basket, washed with nitric acid, washed with water, e Invert the processing basket at the intersection, and transfer the work to a basket exclusively for hexavalent chromium film processing (the empty basket is returned to the position D by a cart). It is transferred to the intersection of Ce4 by the carriage of the transferring means e4, hexavalent chromium film processing is performed on the line C, and after the processing, the work is opened in the container by the reversing machine of the line CC ', and the processing is completed. After that, it is the same as 1).
[0025]
4) In the case of the baking treatment process B pass and the hexavalent chromium-free film treatment process D, the work is moved to the intersection of the DE line by the conveying means E, transported by the carrier together with the treatment basket, and washed with nitric acid, water, hexavalent chromium. After the steps of free film treatment, water washing, water washing and rinsing, the wafer is transferred to the moving means e3 and transported to the Ge-e3 intersection. In the line G, the work is easily dehydrated and dried by the reversing machine, and the process is completed.
[0026]
【The invention's effect】
Since the present invention is constructed and operates as described above, hexavalent chromium film treatment and hexavalent chromium free film treatment, and baking treatment and four steps generated from the presence or absence of a baking treatment pass are performed on one line. It can be performed selectively and is suitable for realizing hexavalent chromium-free while maintaining the hexavalent chromium film treatment process within the allowable range. Since there is no danger of mixing, there is a remarkable effect such as high safety and improved capital investment effect.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a post-processing system for galvanizing according to the present invention.

Claims (1)

In zinc plating capable of performing zinc plating, baking treatment, and hexavalent chromium film treatment, a step A of performing zinc plating and an accompanying treatment, and a step B of performing a baking treatment on a work that has undergone the zinc plating step A
And a step C of performing hexavalent chromium film treatment on the work having undergone the zinc plating step A
And a step D for performing a hexavalent chromium-free coating process on the work that has passed through the zinc plating step A, and the transfer means E connects the step A with the step B and the step D to move the work. Along with
1) Baking treatment step B and hexavalent chromium film treatment step C,
2) Baking treatment step B and hexavalent chromium-free coating treatment step D,
3) Baking treatment process B pass, hexavalent chromium film treatment process C,
4) Baking process B pass, hexavalent chromium-free coating process D,
A post-processing system for zinc plating, wherein the four types of post-processing can be executed.

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