Trueflaw cracks are real

Trueflaw's patented third generation crack production technique differs completely from previous defect production techniques since the cracks are grown by inducing thermal fatigue to the metal. This causes the crack to initiate and propagate like in-service cracks. Thus the NDE response of Trueflaw cracks, in all examination methods, corresponds to the response of service-induced cracks. As a result, the true performance and reliability of the NDE performance can be determined.

Trueflaw has the best know-how in the world in producing natural cracks

Trueflaw has a solid knowledge of cracks and thermal fatigue of metals. With this knowledge, a third generation defect production method was developed. The controllable method is based on thermal fatigue loading the metal resulting in a crack that represents a service-induced crack. At this moment, Trueflaw is the only company in the world that produces controllably grown, real, third generation cracks.

Metal fatigue makes the cracks propagate

The crack initiation point is heated and quenched by following exactly the predetermined settings. This results in controlled crack growth.

Due to the high repeatability it is possible to grow exactly the needed crack in the desired location in the specimen. The characteristics of these thermal fatigue cracks are also similar to the characteristics of stress corrosion cracks and mechanical fatigue cracks.

We have over 300 detailed crack production recipes

Over 1000 cracks have been produced with the equipment that Trueflaw has developed, and of those 300 have been destructively examined. The production parameters of every single crack is recorded and saved. Also the characteristics of the examined cracks are documented. By comparing and analyzing the acquired data a vast, continually developing and focusing databank has been created. This is an essential source when defining production parameters of new cracks.

We guarantee a ± 1 mm depth tolerance for the crack

Each one of our crack production recipes has unlimited repeatability, since following the same production parameters results in an identical crack.

As an indication of accuracy and reliability of the production method, we guarantee a ± 1 mm tolerance for the depth.

Nothing is left to chance when we produce cracks.

Crack growth is influenced significantly by the material of the specimen as well as the geometry. The strength of the material and local changes in the strength e.g. at weld seams, can affect crack growth significantly. In practice, cracks grow differently in different specimens and Trueflaw procedure in each case is validated separately. Our primary role is to increase reliability. And in that respect we leave nothing to chance.

Our crack delivery process is divided into four phases:

Defining the problem / aim

We start by defining the needs of our customer, i.e. what kind of a crack is needed and in what kind of specimen. The location of the crack is exactly defined and also whether any of the defined factors would be critical for crack production.

In order to achieve the desired crack we use very specific production parameters and production recipes. Trueflaw has a vast recipe databank and if a valid recipe for a similar crack size in a similar material can be found, crack production can start immediately. If suitable recipe does not exist, such is created through destructive validation.

Validation

The suitability of the produced validation crack for the intended use is verified together with our customer after the crack depth has been destructively validated.

In validation, a similar crack is produced in a mock-up specimen that represents the actual specimen. To confirm the crack size and other characteristics the mock-up specimen is destructively examined.

The production recipe for the actual crack production is based on this examination.

Approval

Our customer approves the results of the destructive validation before actual crack production.

Production

Crack production in the actual specimen is based on a valid recipe. By following the recipe the number of identical cracks that can be produced is unlimited.