Page 28 - Steel Tech India eMagazine Volume October 2023
P. 28

92/     Ć ,668(   Ć 2FWREHU

             WR  FRUURVLRQ  GXH  WR  WKH  VPDOO  GHFUHDVH  RI  DOOR\LQJ
             HOHPHQWV  7KH VXVFHSWLELOLW\ RI (5: SLSH WR JURRYLQJ
             FRUURVLRQ ZDV UHFRJQL]HG WR EH UHODWHG WR WKH FKHPLFDO
             FRPSRVLWLRQ   SDUWLFXODUO\  VXOSKXU  FRQWHQW   RI  WKH  SLSH
             DQG WR WKH XVH RI D SRVW ZHOG KHDW WUHDWPHQW  )RU (5:
             SLSHV PDGH IURP SODLQ FDUERQ VWHHOV ZLWK KLJK VXOSKXU
             FRQWHQW  RI  PRUH  WKDQ         ZW     JURRYLQJ  FRUURVLRQ
             KDV  FRQWULEXWHG  WR  QRQ PHWDOOLF  PDQJDQHVH  VXOSKLGH
              0Q6   LQFOXVLRQV   0Q6  LQFOXVLRQV  OHDG  WR  6 HQULFKHG
             UHJLRQ  EHFDXVH  RI  WKH  UDSLG  KHDWLQJ  DQG  FRROLQJ  LQ
             (5: SURFHVV  :KHQ HOHFWULF UHVLVWDQFH ZHOGHG FDUERQ
             steel pipe was exposed to aggressive waters, grooves   )LJ    &RUURGHG IUDFWXUH VXUIDFH
             FDXVHG E\ WKH UHGLVWULEXWLRQ RI VXOSKLGH LQFOXVLRQV DORQJ
             WKH ZHOG OLQH ZHUH IRUPHG LQ WKH ZHOG  7KH PDWHULDO DW   WKH  HPEULWWOHPHQW  GXH  WR  K\GURJHQ  DEVRUSWLRQ  LQWR
             WKH ERQG OLQH LV DQRGLF WR WKH VXUURXQGLQJ PDWHULDO DQG   WKH  VWHHO  LQ  WKHVH  HQYLURQPHQWV   + 6  SRLVRQV  WKH
             WKH  UHVXOW  LV  D  9 VKDSHG  JURRYH  ZLWK  WKH  DSH[  RI  WKH   K\GURJHQ  UHFRPELQDWLRQ  FDWKRGLF  FRUURVLRQ  UHDFWLRQ
                                      [3]
             V  centred  on  the  bond  line    7KLV  W\SH  RI  FRUURVLRQ   WKXV  IDYRXULQJ  DWRPLF  K\GURJHQ  DEVRUSWLRQ  LQWR  WKH
             LV RIWHQ FDOOHG DV ³JURRYLQJ FRUURVLRQ ´ 7KH SRVW ZHOG   PDWHULDO  1LFNHO LV GHWULPHQWDO WR 66& UHVLVWDQFH  6WHHOV
             KHDW WUHDWPHQW ZLWK KLJKHU WHPSHUDWXUH FDQ UHGXFH WKH   FRQWDLQLQJ PRUH WKDQ   ZW  1L DUH QRW UHFRPPHQGHG
             VPDOO  FKDQJH  LQ  FKHPLFDO  FRPSRVLWLRQV  WKURXJK  WKH   IRU  VHUYLFH  LQ  VRXU  HQYLURQPHQWV   7KH  VXVFHSWLELOLW\
             GLႇXVLRQ SURFHVV DQG FDQ WKXV LPSURYH WKH UHVLVWDQFH   RI ZHOGPHQWV WR 66& DSSHDUV WR EH JUHDWHU WKDQ WKDW
             to grooving corrosion.                             RI  WKH  SDUHQW  PHWDO   7KH  KLJK  KDUGQHVV  DQG  UHVLGXDO
                                                                VWUHVVHV UHVXOWLQJ IURP ZHOGLQJ DUH EHOLHYHG WR LQFUHDVH
             6WUHVV FRUURVLRQ FUDFNV XVXDOO\ VWDUW IURP FRUURVLRQ SLWV   the susceptibility.
             and  proceeds  transgranular,  or  intergranular  through
             WKH  PHWDO   &UDFNLQJ  LV  RIWHQ  FKDUDFWHUL]HG  E\  FUDFN       0HWDOOXUJLFDO IDFWRUV LPSDFWLQJ WKH ZHOGDELOLW\
             EUDQFKLQJ DQG XVXDOO\ KDV D GHOD\ WLPH SULRU WR FUDFN        (ႇHFW RI UHVLGXDO VWUHVV
             LQLWLDWLRQ  ZKHUHDV FRUURVLRQ SURGXFWV DUH RIWHQ IRXQG   Residual stress as the stresses that would exist in the
             DORQJ  WKH  IUDFWXUH   :HOGLQJ  SDUDPHWHUV  LQÀXHQFH  WKH   PDWHULDO LI DOO H[WHUQDO ORDGV ZHUH UHPRYHG  %DVHG RQ
             DPRXQW DQG GLVWULEXWLRQ RI UHVLGXDO VWUHVVHV EHFDXVH   WKH PHFKDQLVP  UHVLGXDO VWUHVVHV DUH FODVVL¿HG LQ WZR
             WKH  H[WHQW  RI  WKH  VWUHVVHG  UHJLRQ  DQG  WKH  DPRXQW  RI   WKRVH  SURGXFHG  E\  VWUXFWXUDO  PLVPDWFKLQJ  DQG  WKRVH
             GLVWRUWLRQ  DUH  GLUHFWO\  SURSRUWLRQDO  WR  WKH  VL]H  RI  WKH   SURGXFHG  E\  WKH  XQHYHQ  GLVWULEXWLRQ  RI  QRQ HODVWLF
             weld  deposit;  this  deposit  is  directly  related  to  the   VWUDLQV   LQFOXGLQJ  SODVWLF  VWUDLQV  DQG  WKHUPDO  VWUDLQV
             KHDW  LQSXW   :HOGLQJ  WKHUPDO  F\FOHV  DUH  RIWHQ  PXFK   7KH VTXHH]H RXW ZKLFK RFFXUV ZKLOH WXEH ZHOGLQJ KDV
             ORFDOL]HG  UHVXOWLQJ LQ VWUDLQV WKDW FDQ FDXVH GLVWRUWLRQV   OLPLWHG LPSDFW LQ HQKDQFLQJ WKH UHVLGXDO VWUHVV DV WKH
             and residual stresses. These residual stresses can be   EHFDXVH WKH FRPSUHVVLYH VWUHVV LV FRQFHQWUDWHG DW WKH
             LPSRUWDQW LQ WKH LQLWLDWLRQ DQG SURSDJDWLRQ RI 6&&
                                                                ZHOGHG  DUHD   7KH  VL]LQJ  UDWLR  LV  D  FULWLFDO  SDUDPHWHU
             6XOSKLGH  VWUHVV  FUDFNLQJ   66&   ZDV  ¿UVW  LGHQWL¿HG  LQ   LQ UHGXFLQJ WKH HႇHFW RI UHVLGXDO VWUHVV DV KLJKHU WKH
             WKH  SURGXFWLRQ  RI  VRXU  FUXGH  RLOV  ZKHQ  KLJK VWUHQJWK   VL]LQJ  UDWLR   WKH  ORZHU  DQG  PRUH  XQLIRUP  WKH  UHVLGXDO
             VWHHOV  XVHG  IRU  ZHOO KHDG  DQG  GRZQKROH  HTXLSPHQW   VWUHVV  7KLV LV PDLQO\ EHFDXVH WKH FRPSUHVVLYH VWUHVV
             FUDFNHG UHDGLO\ DIWHU FRQWDFW ZLWK SURGXFHG ZDWHU WKDW   LV  GLVWULEXWHG  DORQJ  WKH  SLSH  FLUFXPIHUHQWLDO   :HOGLQJ
             FRQWDLQHG + 6  66& ZDV QRW H[SHULHQFHG E\ UH¿QHULHV   LQKHUHQWO\ LQYROYHV WKH UDSLG KHDWLQJ DQG FRROLQJ RI WKH
             DQG  SHWURFKHPLFDO  SODQWV  XQWLO  WKH  LQWURGXFWLRQ  RI   PDWHULDO  FUHDWLQJ VLJQL¿FDQW WHPSHUDWXUH JUDGLHQWV  $V
             KLJK SUHVVXUH  SURFHVVHV  WKDW  UHTXLUHG  KLJK VWUHQJWK   the welded joint cools, it contracts, and the expansion
             EROWLQJ  DQG  RWKHU  KLJK VWUHQJWK  FRPSRQHQWV  LQ  JDV   XQGHUJRHV  WKHUPDO  H[SDQVLRQ  DQG  FRQWUDFWLRQ
             FRPSUHVVRUV   :LWK  WKH  LQFUHDVHG  XVH  RI  6$:  IRU   Residual  stresses  are  generated  during  the  process,
             SUHVVXUH  YHVVHO  FRQVWUXFWLRQ   LW  ZDV  IRXQG  WKDW  ZHOG   DQG  WKH\  DUH  RIWHQ  WHQVLOH  LQ  QDWXUH   7KHVH  WHQVLOH
             GHSRVLWV  VLJQL¿FDQWO\  KDUGHU  DQG  VWURQJHU  WKDQ  WKH   UHVLGXDO VWUHVVHV FDQ FUHDWH ORFDOL]HG UHJLRQV RI KLJKHU
             EDVH PHWDO FRXOG EH SURGXFHG  7KLV OHG WR WUDQVYHUVH   VWUHVV  PDNLQJ WKHP VXVFHSWLEOH WR FUDFN LQLWLDWLRQ  7KH
             FUDFNLQJ  LQ  ZHOG  GHSRVLWV   +LJK VWUHQJWK  VWHHO  SLSHV   +$=  KHDW DႇHFWHG ]RQH  LV SDUWLFXODUO\ YXOQHUDEOH WR
             XVHG  LQ  GULOOLQJ  DQG  FRPSOHWLRQ  RI  RLO  DQG  JDV  ZHOOV   FUDFNLQJ  GXH  WR  WKH  FRPELQDWLRQ  RI  HOHYDWHG  UHVLGXDO
             PD\  H[KLELW  GHOD\HG  66&  IDLOXUHV  LQ  HQYLURQPHQWV   VWUHVVHV  DQG  DOWHUHG  PDWHULDO  SURSHUWLHV   5HVLGXDO
             FRQWDLQLQJ  + 6   7KHVH  IDLOXUHV  UHVXOW  PDLQO\  IURP   VWUHVVHV  LQ  WKH  +$=  FDQ  LQFUHDVH  WKH  ULVN  RI  FUDFN

                                                                                                    STEEL TECH
   23   24   25   26   27   28   29   30   31   32   33