Physical and chemical tests on head base material test plates
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Should the head base material test plate on the product be subjected to physical and chemical testing after the product is welded and the overall heat treatment is completed, or should the physical and chemical testing be performed before the head is pressed and assembled and welded with the cylinder?
Head base material test plate? Main control requirements? The purpose of testing! Once you know this, you know how to do it!
Heat treatment is carried out together with the represented head, and then samples are made and physical and chemical tests are carried out, which must be completed before the pressure test. The attached picture comes from the head standard
The reason why this head is equipped with a base material test plate is because the supply status of the material has been changed. My understanding is that after the test plate participates in the entire pressing process and normalizing and tempering after pressing, it can be used for physical and chemical tests. There is no need to wait for the completion of welding to the cylinder before conducting physical and chemical tests.
Of course, it is better to conduct physical and chemical tests as early as possible, but sometimes the product delivery time is urgent, and the subsequent assembly work will not be done until the physical and chemical tests are completed.
Detailed analysis of the specific situation. If there is heat treatment after welding, you must wait until the welding with the cylinder is completed. After heat treatment in the furnace, perform physical and chemical experiments.
The reason why the head is equipped with a product test plate is because its supply status is changed during pressing. The purpose of physical and chemical testing is to detect whether the mechanical properties and impact energy of the head base material test plate meet the requirements after the pressing is completed. It does not have much to do with whether there is post-weld heat treatment in the later stage, because the later heat treatment is only post-weld heat treatment and cannot reach the temperature at which the material properties change.
This post was last edited by zjq1962 on 2019-1-23 12:27. The original poster is talking about the base metal heat treatment test piece, and my friend on the 7th floor is talking about the product welding test piece. Post-weld heat treatment does not change the heat treatment state of the material.
Since it is a base material test plate, it must be a test plate that has been heat treated to restore performance. Taking normalizing as an example, after the head welding is completed, the test plate and the head should be normalized in the same furnace, and then the physical and chemical properties of the test plate are tested to verify whether the performance of the base material that has been degraded by compression molding has been restored to the supply level. The second situation mentioned by the poster is for welding test plates. It means that if a product has a welding test plate and the weld it represents requires post-weld heat treatment, the welding test plate must be subjected to post-weld heat treatment in the same furnace or the same process as the weld of the product it represents. There are two concepts with the first situation.
The test of the head base material heat treatment specimen after the overall heat treatment of the product can better illustrate the actual base material state of the head. However, if the head is processed outsourced, it will be embarrassing if the base metal heat treatment test piece fails at this time, and the outsourced manufacturer will shirk all responsibility.