Application for Optimization of Laser Beam Welding by Ultrasonic Wave Superposition

The poten­ti­al of ultra­so­nic wave super­po­si­ti­on to impro­ve the pro­per­ties of laser beam wel­ding was inves­ti­ga­ted using sta­tio­na­ry and moving Pie­zos­ha­ker-Sys­tem at the Depart­ment of Cut­ting and Joi­ning Manu­fac­tu­ring Pro­ces­ses (tff) at the Uni­ver­si­ty of Kas­sel. An examp­le of this is the test on the high-strength steel alloy 22MnB5, which is pre­sen­ted here. Adap­t­ati­on to other wel­ding pro­ces­ses and mate­ri­als is possible. 

The influ­en­ces of the various exci­ta­ti­on para­me­ters of the Pie­zos­ha­ker on the ultra­so­nic wave super­po­si­ti­on were inves­ti­ga­ted, e.g. the dis­tri­bu­ti­on of the AlSi-coa­ting par­ti­cles wit­hin the joi­ning zone as well as the weld seam pro­per­ties [1].

The isi-sys Pie­zos­ha­ker-Sys­tem was used for the moving wave super­po­si­ti­on, as shown in Fig. 1 The sys­tem con­tains a 2‑channel Piezoam­pli­fier of the HPDA‑0–180-2C series and two Pie­zos­ha­kers of the PS-W-02 seri­es. The Pie­zos­ha­kers are firm­ly con­nec­ted to the laser optics via a mount and are moved rela­ti­ve to the com­po­nent sur­face at a defi­ned distance from the laser beam. The­se are pres­sed onto the com­po­nent sur­face with a defi­ned for­ce using pneu­ma­tic cylin­ders. Uneven­ness and dif­fe­ren­ces in the thic­kness of the joi­ning part­ners can be compensated.
















Fig. 1 (left): The dis­tri­bu­ti­on of the AlSi-coa­ting in com­pa­ri­son without (a) and © and with (b) and (e) influ­ence of an ultra­so­nic wave super­po­si­ti­on by isi-sys Piezos­ha­ker during laser beam wel­ding with fal­se-color images of EDS-ana­ly­sis (d) and (f) [1]

Fig. 2 (right): Super­im­po­sed SEM-images and sec­tion­ed inver­se pole figu­re map­pings (IPFM) of a weld seam without (a) and with ultra­so­nic super­po­si­ti­on (b) mea­su­red with elec­tron back­scat­ter dif­frac­tion shown as inver­se pole figu­re in Z‑direction [1]

[1] Publis­hed in: C. Wolf, S. Völ­kers, I. Kryu­kov, M. Graß, N. Som­mer, S. Böhm, M. Wun­der, N. Köh­ler und P. Mäckel, „Enhan­ce­ment of Welda­bi­li­ty at Laser Beam Wel­ding of 22MnB5 by an Entrai­ned Ultra­so­nic Wave Super­po­si­ti­on,“ In: Mate­ri­als 2022, Bd. 15, 4800.

NIST (National Institute of Standards and Technology) using Vic-3D for digital image correlation (DIC)

NIST is using the Vic-3D digi­tal image cor­re­la­ti­on (DIC) sys­tem to ana­ly­ze stress in brid­ges. By using DIC, they try to under­stand the impact of stres­ses and strains on the metal con­nec­tors of brid­ges in order to avoid dama­ge or failure.

NIST is pre-strai­ning a wide pla­te with digi­tal image cor­re­la­ti­on (DIC) to deter­mi­ne the small-sca­le spe­ci­men sec­tio­n­ing plan:

NIST is con­duc­ting a CWP test with digi­tal image cor­re­la­ti­on (DIC) to deter­mi­ne local and remo­te strains used to deter­mi­ne the Ten­si­le Strain Capa­ci­ty of a fla­wed pipe girth-weld:

NIST is making an SE(T) test with digi­tal image cor­re­la­ti­on (DIC) showing the asym­metric strain gra­di­ent of a spe­ci­men not­ched in the heat-affec­ted zone: