Seek the heat treatment process for 16MnD forgings
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For 16MnD forgings, in accordance with the requirements of standard 4727, the supply condition should be quenching + tempering. I would like to know how the processing procedure should be established. For low-alloy structural steel forgings, the majority of heat treatment requirements are normalizing or normalizing + tempering; alloy steel forgings can indeed be treated by quenching + tempering. But why does standard 4727 require quenching for this material, while other forging standards specify normalizing + tempering for it? I would appreciate advice from experts who have used this material.
“For 16MnD forgings, in accordance with the requirements of standard 4727, the supply condition should be \"quenched + tempered\", which shouldn’t present any difficulties! ! In fact, the quenching and normalizing temperatures for 16MnD forgings are the same; the only difference lies in the cooling method, with one being water cooling and the other air cooling. Process: Quenching at 900–930°C with water cooling, followed by tempering at 600–630°C with air cooling. For reference only! !
It’s not the case that all spheres containing hydrogen sulfide media require post-weld heat treatment. It is necessary to check whether it is wet hydrogen sulfide; if so, post-weld heat treatment must be carried out. Under normal circumstances, spherical storage tanks used to hold LPG and liquid ammonia require post-weld heat treatment. The purpose of heat treatment is to eliminate residual stresses after welding and to minimize stress corrosion as much as possible.
The purposes achieved by the two processes are not exactly the same
This material can be effective for forgings with a cross-sectional dimension of 300 or less through quenching and tempering, enabling the formation of a sorbite structure and thereby improving the mechanical properties of the forgings. However, for forgings with larger cross-sectional dimensions, the effect is not significant.
The hardness that can be achieved after quenching and tempering is not specified in the standards for low-temperature forgings, unlike in 4726 where the hardness for 16Mn is given