Indentation center adjustment method of microhardness tester
        The microhardness tester is easy to operate and reliable, and it is widely used in China. But improper handling and use, the indentation often tends to deviate from the center of the field of view. If the indentation is still in the field of view, it is not difficult to adjust the center. When the indentation deviates far from the field of view, it is difficult to resist the indentation by        conventional methods. We have summarized the following simple methods based on years of experience, and the results are very good. Regardless of whether the indentation deviates from the township, the adjustment center work can be completed within half an hour.
1.Basic steps
        (1) Adjust the trajectory of the stage on the guide rail to be parallel to the line connecting the indenter to the center of the viewing field;
        (2) Change the two-dimensional search mark in the field of view to the one-dimensional search mark in the direction of the parallel rail.
2.Method
       (1) Push the stage to the far right, and only push the cutting stage on the guide rails to make a series of indentations, and the distance between adjacent indentations, that is, the moving amount of the stage to the left each time should be less than the visual The field diameter ensures that more than two indentations can appear in one field of view. The connection between the indentation is the movement track of the stage on the guide rail
       (2) Push the stage to the left and loosen the guide rail fastening bolts and the left and right limit screws of the stage.
       (3) Move back and forth and slightly turn the guide rail to observe the position of the pressure hole connection in the line of sight. Because of the indentation into a long string. Therefore, the original two-dimensional point finding is simplified to a one-dimensional line finding perpendicular to the direction of motion of the guide rail. Fix the guide rail when the indentation connection is adjusted to the horizontal diameter of the field of view.
       (4) Make another indentation and adjust the left and right limit screws of the stage until the indentation is in the center of the field of view, that is, one-dimensionally find a point parallel to the direction of the guide rail.
3.Description
       (1) When making the above adjustments. Do not twist the horizontal and vertical cabinet section screws of the stage.
       (2) When it is believed that the loading zero point is reliable, it is advisable to push the stage to draw an indentation line without unloading the minimum load on the very soft test ocean. Then complete the aforementioned line finding and point finding steps.
       The above is the reference material-Laizhou Lailuote Testing Instrument Co., Ltd. (formerly Laizhou Huayi Testing Instrument Co., Ltd.) http://www.lailuote.com Several problems in the use of standard hardness blocks
1.Can both sides of the standard hardness block be used?
       Most of them don't work, only hammering Brinell hardness block can use two sides. During the production and calibration of the hardness block, the main purpose is to ensure the surface quality and hardness uniformity of the measurement surface. Therefore, the surface roughness of the measurement surface and the supporting surface are generally different. The calibration of the hardness block is only performed on the measurement surface, and the support There is no requirement for hardness value or hardness uniformity on the surface. Would you like to calibrate the hardness tester with something unknown or unreliable?
       Generally, the side marked with the hardness standard value is the measurement side, and the side with the calibrated indentation of the hammered Brinell hardness block (Brinell bar) is also measured.
2. I accidentally beat the hardness on the reverse side!
       Don't do this kind of "exploration" in the future.
       If you don't hit too much, use a file to smooth the surface bumps on the support surface caused by the hardness of the wrong hit.
       It is directly used for support without grinding. On the one hand, the supporting surface cannot be in good contact with the test table surface (for Rockwell hardness test, it can directly cause a large error) to affect the measurement accuracy, on the other hand, it may damage the test table surface. Unfortunately, the displacement of the indenter during the pressing process may also damage the indenter.
3.Can the hardness block be used after its expiration date?
       It is generally not recommended to use an expired hardness block, which does not mean that the hardness block is not good. Just as we do not eat expired food, it is not necessarily because expired food must be moldy.
       However, the hardness of the material has a certain aging effect, that is, the hardness will change over time. Although most of the hardness blocks produced by formal enterprises have undergone artificial and natural aging, the hardness changes are not large, but it will be more comfortable to use after re-verification according to the verification cycle.
4. The problem of the hardness value of the hardness block
       When selecting the hardness block, we have a principle: that is, as close as possible to the hardness range of the test piece. However, it is impossible for commercial standard hardness blocks to cover the entire hardness range. This method cannot be produced. On the other hand, the process method cannot be systematic and standardized. Therefore, the manufacturers of hardness blocks generally use the hardness blocks for verification as specified in the verification regulations. The scope of production.
        If you have special needs, you have to contact the hardness block manufacturer to make it. Of course, the price of customized hardness blocks will be higher, and some of them will be difficult to manufacture, and the manufacturing cycle will not be short.
        Usually the hardness tester is used in industry. After the hardness tester is calibrated with the hardness block of the verification range, there will be no big problems (or the accuracy is sufficient) when measuring the hardness of other ranges.
5.Can the hardness block be used if it is rusted?
        If the rust is heavy, it has to be scrapped. It may be used if it is only slightly rusted locally.
        If only the supporting surface is rusty, simply sand it and remove it.
        If there is rust locally on the measuring surface, you should avoid testing here. Even if you remove the rust, the original surface will no longer exist, and the hardness may of course be different.
        Instead of racking your brains to find a remedy, it is better to prevent it in advance. After the hardness block is used up, it should be re-coated with anti-rust grease or wrapped with anti-rust paper
        The above is the reference material-Laizhou Lailuote Testing Instrument Co., Ltd. (formerly Laizhou Huayi Testing Instrument Co., Ltd.) http://www.lailuote.com