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Products & Technique Management Department,Baoshan Iron & Steel Co.,Ltd.,Shanghai 201900,China

Abstract: At present,iron content in a galvanneal coating is determined by an atomic absorption spectrometer (AAS) in Baosteel.The mass of a sample is recorded by operators two times on paper,then the mass of the coating is manually calculated and input in a computer.With the aid of a communication program between an AAS and an electronic balance (EB),the above process can be modified.First,the mass of a sample is sent to a computer by the EB.Second,the mass of the coating is calculated by the computer automatically.Finally,the iron mass is uploaded to the communication program,and the iron content can also be calculated automatically.As such,the modified process is more efficient.

Key words: galvanneal steel sheet; iron content; automation; communication program

1 Introduction

Iron content in the galvanneal coating of a GA sheet should be tested for its effect on production performance so that it can be maintained within a proper range.

According to the international standard ISO 17925:2004,iron content can be determined by an induc-tively coupled plasma atomic emission spectrometry method or a flame atomic absorption spectrometry (FAAS) method.

2 Industry status and problems

The classic inspection method used by Baosteel is FAAS (Fig.1).In the process,the “First time wei-ghing”,“Second time weighing”,and “Difference calculation” are recorded and calculated by the operators.In addition,the difference between the two tunnels also requires the operators to input to the software of the FAAS.

Fig.1 Procedure of iron content determination of galvanneal coating

Owing to the increasing production of GA sheets and uneven sample volume distributions,the current iron content detection method is too complex.It is time-consuming and easily prone to errors.

3 Improved scheme

A special communication program is designed bet-ween an atomic absorption spectrometer (AAS) and an electronic balance (EB).

First,“First time weighing” and “Second time weighing” are transferred from the EB to the com-puter,instead of being recorded by the operators.Second,the computer calculates the difference between two times weighing automatically,so that operators do not need to calculate it.Finally,the com-munication program can calculate the iron content in the galvanneal coating with the mass of iron deter-mined using the AAS and the mass of zinc-iron-alloyed coating.

4 Design and discussion

Fig.2 shows the operating interface of communi-cation program between the AAS and the EB.

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Fig.2 Operating interface of communication program between the AAS and the EB

4.1 Sample numbers

It is time-consuming if all sample numbers are input manually for numerous samples.In addition,the data will not be uploaded if the sample number is incorrectly input,so the communication program should have a function to import sample numbers.

If a sample is encoded,we can search it by click-ing “Command query”.All signals of the samples to be determined are displayed in the left window.When the operators receive samples,they can select the appropriate sequential serial number and press the “OK” button.Then,the information will be input into the “Test result” window on the right.

If a sample is not encoded,it can be manually registered in the software.

4.2 Coating mass

The mass per unit area of the coating can be determined from the mass difference of a sample before and after stripping.

We connect the EB to the computer with the communication program,then click the “Open balance communication port” button.The mass of the sample before coating stripping is uploaded to “First time weighing”.Then,the dry sample after coating stripping is uploaded to “Second time weighing”.The communication program will auto-matically calculate the difference between the two weighings—coating mass—so that artificial calcula-tion errors will be avoided.

All original data measured by EBs are retained in electronic documents.The original record book is replaced.

4.3 Iron content in the galvanneal coating

Iron content is determined by the FAAS method.After clicking the “Read AA file” button,the result of the iron mass is uploaded to the “Test result” window.The communication program can calculate the iron content in the galvanneal coating with the iron mass determined using the AAS and coating mass,as shown in Section 4.2,so that the operators do not have to manually input hundreds of coating mass to the software of the AAS.The procedure works efficiently without errors.

4.4 Other functions

4.4.1 Data copy

For some samples,called “6 points”,there are six pieces of disks in each sample volume.For others,called “2 points”,there are two pieces of disks in each sample volume.However,the number of disks should be six instead of two so that it can be sent.The operators have to fill the remaining four spaces manually if a sample is “2 points”.Now,with the aid of a data copy function,the operators may just click the “Data copy” button.

4.4.2 Standard samples registration

In addition to the samples from products,a communication program between the AAS and the EB is suitable for determining standard samples.The sequential serial number in “Standard number” is input,an appropriate “Standard part” (e.g.,TD or BW) is chosen,and the “Standard samples registration” button is clicked.

4.4.3 Sample retesting

If the result is abnormal,the sample should be retested.It is not conducive to quality control if the new result covers the old one since the sample number is the same.

Thus,a sample retesting function is added to the communication program.After selecting the sample to retest and clicking “Retest flag”,another record is added,whose sample number is “R+original sequential serial number”,so that the two results could be kept together.In addition,the retest result can be directly uploaded to L2.The operators do not have to modify data manually.

4.4.4 Data control

If there are hundreds of samples in each turn,the sequence of samples or weighing is error-prone.In addition,an entire batch of test results may be affected.Therefore,a warning function is also set up in the communication program.When the coating mass is abnormal,the communication pro-gram will warn the operators automatically by turning the data into red,so that the operators can immediately detect the problem and correct errors.

5 Application

Determining iron content in the galvanneal coating is more efficient with the communication program between the AAS and the EB.

As an example,for 180 sample pieces,the time of manual weighing and calculation is shown in Table 1,and the time of weighing and calculation by the AAS/EB communication program is shown in Table 2.

Table 1 Time of manual weighing and calculation min

Table 2 Time of weighing and calculation by the AAS/EB communication program min

With the incorporation of the communication program,the operation time is reduced from 65 min to 20 min,and work efficiency is improved by 69% (Tables 1 and 2).Besides,the AAS operators do not have to input the difference to the AAS software.After the determination,results can be uploaded directly to the communication program.

6 Conclusions

Iron content determination of the galvanneal coating is easier with the development and application of a communication program between the AAS and the EB.Original data are uploaded,and the communication program will calculate automatically.

On the one hand,work efficiency is improved by reducing the operation time.On the other hand,results are more accurate without human errors.Finally,replacing paper records with electronic records will be beneficial for the environmental protection.