Forging thickness issue
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I would like to ask the experts: what should be done when the thickness of a forged part exceeds the standard specifications? As specified in JB4727, for 16MnD the thickness is limited to 300 mm or less; what should be done if the thickness exceeds 300 mm? Is it allowed to use it?
There’s nothing that can’t be used; it’s just not recommended. It is better to choose one with more suitable strength and other properties.
In fact, forgings are similar to sheets of metal; if their thickness exceeds the specified limit, their quality may decline. Since the final shaping of forgings involves a series of processing steps, significant segregation can occur, leading to differences in properties between the longitudinal and transverse directions, as well as between the surface and the interior.
When the thickness exceeds the specified value, there is no basis for determining the allowable stress; in such cases, a grade with higher strength should be used.
It can be used, but its required stress needs to be reduced – it should not exceed 80% of the allowable stress; for greater thicknesses, 50% is appropriate. The greater the thickness, the more difficult it is to manufacture, and it becomes impossible to guarantee all aspects of its performance. ASME has regulations regarding this
Modify the material; 20MnMoD can be used
It can be used, but the quality of the forgings cannot be guaranteed; it is recommended to use a different material