Uporovno točkovno varjenje naprednega visokotrdnega martenzitnega jekla

Lukek, Aleksander (author), Klobčar, Damjan (mentor), Tušek, Janez (co-mentor)

V sodobni avtomobilski industriji je zaradi ekoloških vidikov vse bolj pomembno, da je masa vozil vse manjša. Zato se v vozila vgrajujejo komponente, ki imajo dobro razmerje med trdnostjo in težo. V ta segment materialov sodijo tudi napredna visokotrdna jekla. V industriji sta zmanjšanje cene in mase komponent zelo pomembna dejavnika. Na ta dva dejavnika lahko vplivamo s sodobnimi tehnologijami in robotizacijo proizvodnje. V diplomski nalogi sem preučeval uporovno točkovno varjenje naprednega visokotrdnega martenzitnega jekla. Pri preizkušanju smo spreminjali jakost varilnega toka od 4,5 kA do 8,5 kA in čas varjenja, ki je znašal od 10 ciklov do 25 ciklov. Po končanem varjenju smo opravili natezno-strižni test, izmerili trdoto in analizirali mikrostrukturo. Glede na dobljene rezultate smo izbrali najbolj primerne varilne parametre. Ugotovili smo, da so najbolj optimalni parametri pri varjenju jekla Docol 1200M pri sili pritiska Fp = 5 kN, varilnem toku I = 6,5 kA in času varjenja 20 ciklov (400 ms).

• Language: Slovenian
• Keywords: - uporovno točkovno varjenje - napredno visokotrdno jeklo - avtomobilska industrija - natezno-strižni test - trdota - mikrostruktura
• Work type: Bachelor thesis/paper
• Organization: FS - Faculty of Mechanical Engineering
• Year: 2017
• PID: 20.500.12556/RUL-94904
• Publication date in RUL: 11.09.2017

Secondary language

• Language: English
• Title: Resistance spot welding of advanced hige strength martensite steel

Abstract

In the modern automotive industry it is increasingly important that the mass of vehicles is lower due to ecological aspects. Therefore, components fitted into vehicles must have a good strength to weight ratio. Advanced high-strength steels also belongs to this segment of materials with high strength properties. In industry, reducing the price and weight of components is a very important factor. We can influence these two factors with modern technologies and connection with robotic welding. This study present the resistance spot welding of high-strength maraging steel. During testing, welding current changed from 4.5 kA to 8.5 kA and the welding time, from 10 cycles to 25 cycles. From the produced welds we made tensile shear tests, measured the hardness and examined the weld microstructure. Based on the results obtained, we selected the most suitable welding parameters. We concluded that the most optimal parameters for welding the Docol 1200M are the pressure Fp = 5 kN, the welding current I = 6.5 kA and the welding time of 20 cycles (400 ms).

• Keywords: - resistance spot welding - advanced high-strength steel - automobile industry - tensile-shear test - hardness - microstructure