JB/T 9221-1999 JB/T 9221-1999 Test method for effective bentonite and effective coal powder in green sand for foundry JB/T9221-1999 Standard download decompression password: www.bzxz.net

JB/T 9221 ---1999
This standard is a revision of ZB/TJ3101190 "Effective bentonite content and effective seacoal content in green molding sand for casting". The original standard has been edited, and the main technical content has not changed. This standard replaces ZB/TJ31011-90 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Foundry Standardization. The drafting unit of this standard is Shenyang Foundry Research Institute. The drafter of this standard is Chen Qiuying.
Test method". Revision
1 Scope
Machinery Industry Standard of the People's Republic of China
Test method for effective bentonite and effective seacoal content in green molding sand
Test method for effective bentonite and effective seacoal content in green molding sand This standard specifies the test method for effective bentonite content and effective seacoal content in green molding sand. JB/T9221--1999
Replaces ZB/TJ31011-90
This standard applies to the test methods for the effective bentonite content and effective coal powder content of green sand for casting of cast iron, cast steel and non-ferrous alloy. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards. Industrial analysis methods for coalbzxz.net
GB/T 212—-1991
GB/T2684-·1981 Test methods for raw sand and mixtures for foundry Foundry terminology
GB/T 5611—1998
JB/T 9227---1999
3 Test methods
3.1 Sampling
Bentonite and clay for foundry
3.1.1 Samples are taken from the old sand before mixing. 3.1.2 The method for selecting samples is the "quartering method" or a sample divider. 3.2 Determination of effective bentonite content in old sand 3.2.1 Reagents
0.2% methylene blue solution (analytical grade), stored in a brown glass bottle. 1% sodium pyrophosphate solution (chemical grade).
3.2.2 Instruments
Burette;
Balance.
3.2.3 Determination steps
Take the raw sand and bentonite used in the workshop and dry them at 105-110°C to constant weight, then place them in a group (5) of 250mL conical flasks. Add 0.1, 0.2, 0.3, 0.4, 0.5g of bentonite and 4.9, 4.8, 4.7, 4.6, 4.5g of raw sand respectively, so that the total amount of raw sand and bentonite in each sample is 5.0g. First, add 50mmL of distilled water respectively, and then add 20mL of 1% sodium pyrophosphate solution respectively after wetting. Shake evenly and heat on an electric stove to boil for 5min. Cool to room temperature in air, and use a burette to drop 0.2% methylene blue solution. When titrating, add about two-thirds of the expected methylene blue solution for the first time, and then add 1-2 ml each time until the test end point. The method for testing the end point is to shake for 30 seconds after each drop of methylene blue solution, and use a glass rod to dip a drop of solution on the medium-speed quantitative filter paper. Approved by the State Bureau of Machinery Industry on June 24, 1999, and implemented on January 1, 2000
JB/T9221---1999
Observe whether there is a light blue halo around the central light blue point. If not, continue to add methylene blue solution, repeat the operation. When a light blue halo appears, let the sample stand for 2 minutes, and then use a glass rod to drip the test solution. If the light blue halo disappears, it means that the end point has not been reached. You should continue to add methylene blue solution until a light blue halo appears, which is the end point of the test. The titration of the methylene blue solution at this time is the blue absorption of the sample.
The blue absorption of each sample is repeated three times according to the above method, and the average value is calculated. However, if any of the two values ​​differs from the average value by more than 10%, the test needs to be repeated. The amount of bentonite added in the sample is the horizontal axis, and the average value of the three methylene blue solution titrations is the vertical axis. The standard curve is drawn as shown in Figure 1. 3.2.4 Calculation of effective swelling content
Weigh 5.0g of old sand dried to constant weight at 105~110℃, place in a 250ml conical flask, determine the titration of methylene blue solution in the sample according to the determination steps in 3.2.3, and then find out the effective swelling content in the old sand from the drawn standard curve. 70F
bentonite,
silica sand, g
bentonite, %
For example: the titration of methylene blue solution of 111 sand is 40mL, draw a line parallel to the horizontal axis on the graph and intersect with the drawn standard curve, then draw a straight line parallel to the vertical axis from the intersection and intersect with the horizontal axis, and then find out that the effective swelling content in the old sand is 5.7%. 3.3 Determination of effective coal powder content in old sand
3.3.1 Instrument
SFL. type recording gas emission tester;
balance.
3.3.2 Determination steps
Heat the gas emission tester to 900℃, weigh 0.01g of coal powder used in production, put it in a porcelain boat (the porcelain boat is pre-burned at 1000℃ for 30min), and then send the porcelain boat to the red hot part of the quartz tube. Immediately plug the rubber stopper, and the recorder starts to record the gas emission of the measured sample. Keep it warm for 7min until no gas is generated. Determine the gas emission of 0.01g bentonite and other additives according to the above method. Finally, determine the gas emission of 1.0g old sand that has been cleaned of iron-containing substances and air-dried by a permanent magnet according to the above method. Determine the same sample three times according to the above method and take the average value. If any value differs from the average value by more than 10%, the test needs to be repeated.
3.3.3 Calculation of test results
The effective coal powder content in the old sand is calculated according to formula (1): 548
Wherein: X———effective coal powder content in the old sand, %; Qi1g of old sand gas generation, ml.
JB/T9221---1999
ZQ:-1g of old sand except coal powder, total gas generation of bentonite and other additives, ml; Q—gas generation generated by 0.01g of coal powder, ml. (1)
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