Non-destruc­tive test­ing of iron castings

Iron cast­ing — oppor­tu­ni­ty and chal­lenge for light­weight construction

Leicht­bau heißt nicht automa­tisch „Leicht­met­all“, denn bei hohen Tem­per­a­turen und Drück­en sind Leicht­met­alle nicht ein­set­zbar. Mit dünn-wandi­gem Eisen- bzw. Stahlguss und neuar­tigem, bion­is­chen Design wer­den Bauteile geschaf­fen, die es mit funk­tion­s­gle­ichen Ele­menten aus Leicht­met­all aufnehmen können. 

Mass sav­ings and high mechan­i­cal prop­er­ties are accom­pa­nied by sig­nif­i­cant tech­no­log­i­cal chal­lenges. Those who are ahead of the game here can also enter the com­pet­i­tive mar­ket for light­weight safe­ty com­po­nents. Process mon­i­tor­ing based on mean­ing­ful inspec­tion data enables high qual­i­ty and ulti­mate­ly more prof­it. Non-destruc­tive test­ing of iron cast­ings with CT can help here.

CT-Aufnahme eines Turboladers
CT Image as a cross sec­tion of turbocharger

Typ­i­cal prob­lems with iron casting.

Cracks in components

Use the mag­ni­fy­ing glass to observe the crack in the com­po­nent in 3D:

Zerstörungsfreie Prüfung von Eisenguss

Crack in a 2D view:

Riss im Krümmer durch CT sichtbar

Pores in components

Use the mag­ni­fy­ing glass to observe the pores in 3D:

Zerstörungsfreies Lolo

Pores in a 2D view:

Pore im Eisenguss

Process for non-destruc­tive test­ing of iron castings

Ser­i­al inspection

Ablauf Serienprüfung bei Microvista

*Note: Scan­ning with­in 24h only by appoint­ment and depend­ing on the num­ber of parts.

Com­pli­cat­ed com­po­nents in high-qual­i­ty end prod­ucts? Major dam­age due to qual­i­ty defects that far exceed the man­u­fac­tur­ing costs of a com­po­nent? Safe­ty-rel­e­vant com­po­nents that require 100% inspection?

In these cas­es, a fast, low-effort inspec­tion such as indus­tri­al com­put­ed tomog­ra­phy is required. Due to ready-made process and automa­tion mod­ules, high lev­els of matu­ri­ty in the inspec­tion process are realised extreme­ly quick­ly and at low cost.


Ablauf einer Bemusterung mit CT

*Note: Lead time by arrange­ment, usu­al­ly < 3 days for stan­dard tasks. 

Need for inspec­tion in case of acute prob­lems in pro­duc­tion? Cus­tomer returns? Qual­i­fi­ca­tion of prod­uct changes?

Reli­able infor­ma­tion on the con­di­tion of the prod­uct, inclu­sions, voids or oth­er prop­er­ties must be avail­able quick­ly in order to react in time and draw the right con­clu­sions. Exper­tise in the plan­ning and exe­cu­tion of the CT scan as well as in the sub­se­quent analy­sis are cru­cial for this.

Iden­ti­fy dif­fer­ences between sim­u­la­tion & reality

A constructor’s imag­i­na­tion and the results of the sim­u­la­tion do not always match the reality.

Cross-sec­tion­al areas of ducts must be with­in spec­i­fied tol­er­ances, oth­er­wise the hoped-for per­for­mance remains behind the expectations.

Querschnittsmessung mit CT
Cross-sec­tion measurement

Iron — not easy for CT systems 

Wall thick­ness plays an impor­tant role in non-destruc­tive test­ing of iron cast­ings with CT, as can be seen here.

Total atten­u­a­tion coef­fi­cient of X‑rays with the ener­gy of 300 keV:
0,74 cm -1 (for com­par­i­son Al: 0.25 cm-1)

For a high qual­i­ty inspec­tion, the ratio I/I0 ≥ 10-5 !
Ablauf CT-Scan
Mögliche Wandstärke beim CT-Scan