Determining the MBN value of G-type connecting rod bolts is a critical process for ensuring the quality and performance of these components. The G-type connecting rod bolts produced by our factory are made from 18Cr2Ni4WA steel. After quenching and tempering, we perform hardness tests to ensure that the bolts meet the required mechanical performance standards. The hardness value must be maintained within a specific range to guarantee the bolt’s strength and durability.
Given the high annual production volume of connecting rod bolts in our factory, conducting hardness tests on a large number of bolts in the field is both time-consuming and labor-intensive. To address this challenge, we use the CTY601 multi-function magnetoelastic testing device, which allows us to test all connecting rod bolts quickly, accurately, and without causing any damage. This method not only improves efficiency but also reduces the need for manual labor and resources.
We have been continuously measuring approximately 150 connecting rod bolts over a period of four months. During this time, we compared the MBN values with the HRC values to establish a correlation between them. By comparing the MBN values with sample numbers and the measured HRC values from the workshop, we were able to analyze how the two parameters relate. However, due to differences in the test locations—where the workshop measures near-surface hardness and the testing center measures core hardness—the results vary.
Specifically, the workshop measurements tend to be slightly lower because the surface layer may be decarburized, while the testing center measures the hardness of the core material. As a result, when the MBN value is high, the HRC value tends to be low, and vice versa. When an MBN value is found to be abnormal, the corresponding HRC value is also typically abnormal. This relationship helps us identify potential issues early in the production process, allowing for timely corrective actions.
This approach not only ensures full inspection of all bolts but also enhances the overall quality control process. It has proven to be an effective and reliable method, making it a promising project for future development.
Set Adjusting Additive and Admixture
For cement based or gypsum based product like mortar or concrete, set adjustment is so necessary, which is important for ensure the application time and early strength development. There are many types of product to change the initial and final setting time. In some case, Set Retarder is adopted to extend the setting for cement or gypsum including tartaric acid, citric acid, sodium gluconate etc. In other case, Set Accelerator is also critical to shorten the setting time and improve the early strength, such as lithium carbonate, lithium sulphate and calcium formate etc. CSA Cement, as fast setting cement, works as fast-setting admixture, which give excellent instant setting effect when used alone or combined with ordinary portland cement. Furthermore, in some fast-setting binder system, retarder and accelerator have to be added together to fine tune the hydration process.
Set retarder,cement retarder,gypsum retarder,set accelerator,early strength agent,tartaric acid,set adjusting admixture
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