Issue 14

M.N

. James et alii,

Frattura ed Inte

grità Strutturale

, 14 (2010) 5-1

6; DOI: 10.3221/

IGF-ESIS.14.01

allo IG to e

ys which do facets on a f ither critical

not exhibit racture surfa or sub-critica

such IG face ce are usually l cracking w

ting during c an indicatio ould be lowe

rack initiatio n that some red. Fig. 3 sh

n and growth form of emb ows typical I

[16]. This rittlement ha G faceting o

is unusual, as s occurred an bserved in th

the presenc d that resista ese alloys.

e of nce

R E

SIDUAL STR

ESSES AND

WELDS

R

esidual consequ of the y

stresses aris ence of man ield or proo es over whic aries with typ , including c e crack grow ts. They als cal phase tra nical propert

e as a conse ufacturing an f strength. h the residu e, nature and hanges to lo th. These st o occur as a nsformation ies, microstru

quence of m d fabrication These region al stresses sel origin [20]. ad eccentricit resses often a consequence s), and are p cture and ge

isfit betwee processes, w s of misfit c f-equilibrate. Type I mac y and failure rise from no of the crack articularly in ometry of th

n various re ith magnitud an occur wi Their influe rostresses can stress durin n-uniform pl growth proc fluenced by e componen

gions [20] an es that local th several di nce on mech affect the p g buckling, a astic deform ess itself (cra thermal proc t or part.

d are hence ly are often a fferent size s anical perfo erformance o nd influence ation or from ck tip plastic esses (e.g. h

an inescap high propor cales and he rmance of al f structures s on the frac assembly m zone and c eat treatmen

able tion nce loys in a ture isfit rack t or

dif the num stre of wa wel

ferent distanc refore also v ber of ways ss and fatigu structural par ke effects, lo ding), mecha

Figure 3 : IG

faceting near t

he crack initiat and 0. hly variable; ominally sim f stress conc ing service ample, peeni onent [23]. ue cracks and . of intermet widespread e lack of accu only used st often has a e ways of de ects. A larg sing low ener n ‘innate’ co e available X s a form of p

ion site in an 013Ti. The st both from p ilar condition entrators suc [21]. Comp ng [22] or co Type II stres corrosion p allic particles xistence and rate 3D info ructural joini deciding influ aling with re e contributio gy X-ray sou ntribution to ray intensity article accele

IF steel contai eel has a yield lace-to-plac s. The exter h as weld toe ressive resid ld-working te ses are interg rocesses. Ty and regions, frequent us rmation on t ng process a ence on the sidual stress n to this un rces, impreci scatter from increased dr rator in whic

ning 0.001C, 0 strength of 17 e within the nal applicatio s, defects and ual stresses chniques, wh ranular in sc pe III stresse and from di e of residual he magnitud nd the resid analysis outc in fracture m certainty ari sion in hole d the welding amatically as h particles (u

.380Mn, 0.004 4 MPa. component, n of cycles o cracks, lead are routine ich are often ale and influ s are of the slocation stre stresses in e e and re-dist ual stress di ome [24]. T echanics ass ses from dat rilling param process [24]. synchrotron sually electro

Si, 0.008P, 0.0

05S, 0.018Nb

Th stru par res per fati suc fro slip cyc loa We ass to eng sur of Fro A s

eir magnitud ctures produ ticularly in th idual stress formance thr gue ‘quality’ h as the initi m interface c processes. lic loading, t d. lding is the essment for w propose very ineering crit face measure measurement m the 1970s ynchrotron l

es can be hig ced under n e presence o profiles dur ough, for ex of the comp ation of fatig oherency, e.g Despite the here is still a most comm elded joints conservativ icality of def ments, e.g. u s, alongside a onwards, th ight source i

and between f load, displ s to significan ly used to considered ence aspects order of atom ss fields, and nhancing per ribution (or r stribution as hus fatigue d essments of a limitations eters and rel light sources ns) are initia

component acement or h t changes in enhance ser as improving of performa ic size and a influence pla formance un elaxation) un sumed in de esign codes t remanent lif associated w atively small were develop lly accelerate

s or eat, the vice the nce rise stic der der fect end e or ith sets ed. d in

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