某压力容器焊接附件的真空热处理

某压力容器的本体和附件均采用D406A（30Si2MnCrMoVE）钢制作，但经真空热处理后附件硬度达50HRC左右，难以机加工。为了尝试用其他材料制造该附件，分别用30钢、45钢和30CrMnSiA钢及H10、H08和H18焊丝与D406A钢焊接，研究了焊接试样按D406A钢工艺真空热处理后的显微组织和力学性能。结果表明，30CrMnSiA钢与D406A钢用H10焊丝焊接的试样经930cC真空加热和2×10^5Pa压力气淬后，硬度为35～40HRC，抗拉强度为1100～1200MPa，无过热组织，达到了要求。

Vacuum Heat Treatment of a Certain Pressure Vessel Attachment

Both body and attachment of a certain pressure vessel were made of D406A （30Si2MnCrMoVE） steel, however, the hardness of attachment was as high as about 50 HRC after vacuum heat treatment and therefore difficult to machine. For this reason, the specimens were prepared by respective welding 30, 45 and 30CrMnSiA steel pieces to D406A steel piece with H10 or H08 or H18 welding wire, and their microstructures and mechanical properties were investigated after being vacuum heat treated by the procedure suitable for D406A steel, to reveal the possibility to use another steel instead of D406A steel for the attachment. The results show that the hardness of 35- 40 HRC, tensile strength of 1100 - 1200 MPa and microstructure not overheating in accordance with the requirements have been obtained for the specimen welded by 30CrMnSiA steel piece and D406A steel piece with HIO welding wire and heat-treated by vacuum heating at 930 ℃ and then gas-quenched under 2 × 10^5 Pa pressure.