林强, 张华, 陈国威, et al. Analysis on Unqualified Pressure Vessel Steel Plate by Nondestructive Test and Optimization of Process[J]. Special Steel, 2017, 38(5): 17-21.
林强, 张华, 陈国威, et al. Analysis on Unqualified Pressure Vessel Steel Plate by Nondestructive Test and Optimization of Process[J]. Special Steel, 2017, 38(5): 17-21.DOI:
The production process of tested 12MnNiVR pressure vessel steel plate (/% : ≤0.15C
0.15~0.40Si
1.20~1.60Mn
≤0.008P
≤0.018S
0.15~0.40Ni
≤0.30Cu
0.02~0.06V) is KR metal desulphurization- 90t BOF- RH- 210~300mm slab casting-rolling to 20~30mm steel plate. The liquid total oxygen content
inclusions number
inclusion size distribution
morphology and ingredient of unqualified specimen of 12MnNiVR pressure vessel steel plate in RH refining and casting process have been studied by scanning electron microscope. Results show that the linear Al
2
O
3
defect formed by rolling is main reason of un-qualification of plate by nondestructive test; with process measures including controlling BOF tapping temperature 1650℃
liqui
d temperature before RH refining ≥l610℃
decreasing oxygen blowing amount in RH refining process
strengthening shielding process and RH cycling time ≥10min
the qualified rate of pressure vessel steel plate by nondestructive test increases from original 96.85% to 99.07%.