: Increasing the strength of permanent joints of additively produced and modern high-strength steels

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23210%2F22%3A43966536" target="_blank" >RIV/49777513:23210/22:43966536 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

: Increasing the strength of permanent joints of additively produced and modern high-strength steels

Original language description

Project focused on the issue of joining additively manufactured and conventionally produced high-strength steels. Experimental work was carried out on TRIP steels (T9: 0,2C-5Mn-3Al-0,58Si and T4: 0,2C-1,7Mn-1,4Al-0,5Si), high strength steels (42SiCr, DOCOL1800; DOCOL 2000) and additively produced maraging steel 18Ni300. In these materials, the mechanical properties are ensured by complex heat-sensitive microstructures, which is a major problem when joining these steels. Therefore, methods of permanent joining were investigated, in which the influence on the microstructure of these heat-treated steels is minimized or completely eliminated. joined samples were subjected to microstructural analyses and a tensile testing according to ČSN EN ISO 6872-1 (butt welds) and ČSN EN 1465 (lapped adhesive joints).Using the laser or electron beam welding, homogeneous and heterogeneous butt welds of high strength steels were performed. Especially beneficial was considered the combination of 18Ni300 (3D printed) steel with 0,2C-5Mn-3Al-0,58Si TRIP steel as it enables the production of hybrid parts, where the printed (smaller, detailed, expensive) part can be welded on a massive forged part (conventionally produced, cheap). It therefore reduces significantly (expensive) 3D printing share of a part. The tensile testing of this weld joint showed ultimate tensile strength of 1200 MPa and a yield strength of 973 MPa, with an elongation A5,65mm of 3.5%. Adhesive bonding was addressed as another method of permanent joining. Three different adhesives were used: one-component heat-curing experimental epoxy adhesive DENATITE XNR6852E-3, two-component epoxy adhesive Auratech AR94440 and two-component acrylic structural adhesive 3M Scotch Weld DP8407NS. The effect of surface pretreatment in following variants was also addressed: greasy surface, degreased surf., sanded, sandblasted, laser treated. The highest joint strengths were achieved with the heat-curing adhesive DENATITE XNR6852E-3. The shear strength ranged from 26 to 33 MPa regardless of the surface pretreatment (even the greasy surfaces achieved as high as 27-28 MPa) and the choice of steel. Considering the size of the glued parts cross-section (25x1,5 mm), equivalent tensile strength of the joint would be cca 430 – 550 MPa. This glue also showed highest adhesion to the steel surfaces.

Czech name

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Czech description

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Type

V_souhrn - Summary research report

CEP classification

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OECD FORD branch

20501 - Materials engineering

Project

<a href="/en/project/EF19_073%2F0016931" target="_blank" >EF19_073/0016931: Improving the quality of the internal grant structure at UWB</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Number of pages

2

Place of publication

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Publisher/client name

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Version

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