-When manufacturing containers from Q345R steel plates with a design temperature of 20 degrees, and heat treatment is used to improve the recovery performance, is it necessary to use test plates?
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-When manufacturing containers from Q345R steel plates with a design temperature of 20 degrees, and heat treatment is used to improve the recovery performance, is it necessary to use test plates? How should item d) of 9.1.1.1 be understood – regarding steel containers in which the material properties are improved or restored through heat treatment during the manufacturing process – does heat treatment after completion of manufacturing mean that there is no need for test plates?
In the manufacturing process of this item, as I understand it, once steps such as rolling the cylinder and pressing the head meet the heat treatment conditions specified in clause 8.1.1, it is considered part of the manufacturing process.
First, it is necessary to understand that clause 8.1.1 refers to cold-formed compression members; generally, for cylinders, unless they are thick and have a small diameter, their deformation rate should be less than 5. As for end caps, they are normally formed by hot pressing
Improving or restoring heat treatment properties means altering the microstructure of the material at room temperature through heat treatment; for example, if the material is in a hot-rolled state, grain refinement can be achieved through normalizing heat treatment, or if the material is in a solution-treated state and this state has been damaged due to the manufacturing process, solution treatment must be carried out again. . .
It has little to do with the design temperature; as long as heat treatment is required to restore the properties of the material, test plates need to be prepared. Of course, if product welding test plates also need to be made at the same time, it is possible to consider preparing them together.
It is necessary to test the plates, and it must be done in the same furnace.
It is important to understand what heat treatment for restoring mechanical properties is. Conventional heat treatment does not require test pieces; it is only necessary to carry out such heat treatment when the degree of cold working deformation is excessive, the heat treatment state is altered during processing, or a different heat treatment state from that of the supplied material is required. Ordinary post-weld stress-relief heat treatments do not require test plates. Not every heat treatment requires a test plate.