Cold working of steel plates requires heat treatment to restore their properties; should normalizing be performed or recrystallization annealing?
Thread Content
The recovery treatment for performance that I understood before referred to returning the material to its condition at the time of delivery, which is usually normalized. Is it sufficient to carry out only a recrystallization annealing treatment and a stress-relief treatment?
My personal understanding is to return to the supply status
The supply condition of the steel plate is determined according to 150.2, not just normalizing or anything similar
First, consider what heat treatment is required after head forming to restore its properties, and then establish the heat treatment requirements for weld evaluation.
Assume that this head has a seam, and this seam requires post-weld heat treatment. Well, this issue actually falls into two categories: 1) First, assemble the panels, and then press them into shape. If it is thermoforming and the forming temperature is above the AC3 temperature, then no heat treatment to restore properties is required. At this point, the weld evaluation requires heat treatment at the transition temperature ； If it is hot forming and the forming temperature is between AC1 and below the AC3 temperature, then the weld evaluation requires heat treatment within the range between the upper and lower transformation temperatures ； If it is cold forming, post-weld heat treatment must be carried out before shaping, followed by heat treatment to restore properties after cold forming ； 2) Form first, then assemble and weld. In this case, it’s relatively simple: after shaping, carry out any necessary heat treatment, then weld, and after welding, perform post-weld heat treatment. It should be noted that the requirement on the general layout for the sheets to be supplied in a normalized state does not mean that the sheets must also be in a normalized state when in use. Therefore, at this point, even if cold forming or hot forming alters the normalized state, recrystallization annealing can be used to restore the material’s properties for conventional materials such as Q245R and Q345R, since the properties of these conventional materials after recrystallization annealing are almost identical to those after normalization. However, in the case of heat-resistant steels such as 15CrMoR, 12Cr1MoVR, etc., there is a significant difference between the normalized state and the recrystallization annealed state; in such cases, the heat treatment intended to restore properties should be in line with the technical requirements or the material quality certificate ；
We understand it the same way, but once the supervisor raised this issue
Thermoforming is not taken into account here; it’s only cold forming that is considered
So it generally returns to the supply state, is that how it can be understood?
Cold-formed refers to the state of the sheet material upon leaving the factory.