Does this head require a heat treatment test plate?
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DN1000, δ34.Q345R head; according to section 150.2, this material requires normalized plates. As mentioned in 150.4 9.2.1.1 c regarding base metal specimens, compressed components that are formed by cold or warm methods need heat treatment to \"restore\" the material’s properties. In the case of 150.4 8.1, if the head is formed by warm forming or cold forming and the degree of deformation exceeds 5%, it is necessary to provide base metal specimens. At present, the forming method for this end cap is not confirmed; for such thickness and diameter, hot forming is generally used. Then I have a question: does a head manufactured by hot stamping of normalized steel plates require a base metal specimen? ? ? Someone mentioned it in the forum, but I didn’t see a clear reply
Refer to Clause 6.4.3 of GB25198-2010: if the finishing temperature is higher than the minimum normalizing temperature, no additional normalizing treatment is required.
It’s not clear whether a test board is needed for this item. Does that mean that no test plates are required if no additional normalizing treatment is carried out?
This post was last edited by gn_1984 on 2019-10-21 at 16:55. The end temperature for thermoforming is above the material’s critical temperature, which is equivalent to a normalization process; this does not change the material’s as-supplied condition. According to Clause 8.1.4 of GB/T150.4-2011 and Clause 6.4.3 of GB/T25198-2010, no further heat treatment is required. As stated in Item a) of Clause 9.2.1.1 of GB/T150.4-2011, the head does not need to have specimens taken from the base material for heat treatment testing.
The heat forming termination temperature should be maintained at or above the minimum normalizing temperature of the material; normalizing is not required after heat forming. This is stipulated in the GB/T25198 standard. It is unknown whether GB/T150 is recognized; at least it is not cited. The capabilities and quality of end cap pressing units vary, and it is difficult to control the finishing temperature. After all, the head pressing process is different from the heat treatment process. It is not recommended to use such a method for important equipment. For ordinary equipment, if such a method is used, at least a base metal test plate should be used for verification.
Diameter of 1000, thickness of 34; the deformation rate should not exceed 5%. If the final pressure temperature that meets the requirements is indicated on the head quality certificate, it can be waived. It’s better not to subject this item to heat treatment a second time.
For test pieces, it is almost impossible to achieve exactly the same deformation and heat treatment condition as those of the actual product. Not very useful for reference. Personal opinion.
Thank you for your reply. Regarding the deformation rate here, RF is roughly 0.172D. The calculated deformation rate of the head exceeds this value.
The base metal test plate does not need to undergo the same deformation as the head; it only requires the same heat treatment.
The poster mentioned a head thickness of 34; it’s not clear whether this refers to the thickness of the material used or the minimum thickness required for forming. If it’s the former, then normalized steel plates aren’t necessary (unless used in temperatures below 0 degrees). If it is not a normalized plate, a heat-treated specimen of the base material should still be provided.