Lamellar tear vs Laminations and Z through Test

[zacharialamsyah]

Dear All

I want to ask some topic which i'm not understand

1.What the differences between Lamellar Tear and Lamination? Because in some reference they are similar and not quite different?

2. Is it Z through test (through thickness test) can detect lamination also, beside its primary functions to detect lamellar tear?

3. If plate was detected have lamellar tear, what actions take to repair that plate, so the plate can reused?

Thank you for response and answer

Regards
Zachari Alamsyah

 

[Haiker]

Lamellar tearing is caused by a load being applied to a plate, beam etc. which tears the material apart. Lamination occurs in rolled products when a gas bubble is confined in the product as it is cast, then rolled creating a void or lack of fusion in the product. Ultrasonic inspection is a useful method of non destructive detection.

 

[metengr]

First, here is some information related to lamellar tesr testing with regards to welding;

http://www.aws.org/wj/supplement/WJ_1973_11_s481.pdf

Laminations are defects in materials, and you can review on your own.

http://saisc.co.za/saisc/downloads/publications/issues/2012/vol_36_jan/TechnicalLaminations.pdf

Z refers to through thickness direction, and volumetric examination.

Typically, lamellar tears are associated with welding and banding in steel plate. If lamellar tears occurred in service, I would not repair the plates because it would re-occur.

 

[weldstan]

Repairs require full excavation of the crack, confirmation of its removal with MT or PT followed by rewelding the base material with a low hydrogen process and then completeing the strength weld with low hydrogen processes. Preheat at 200 F (100 C) is recommended.