Mankind has been familiar with different metals and metal alloys since the Iron Age. Steels are indispensable material of modern mechanical and civil engineering. Parallel with the development of steels the joining technologies and procedures are also developed. The most demanding load-bearing constructions are made of steels which give us high strength at the lowest possible own weight. S1100QL steel, with a guaranteed yield strength of 1100 MPa, achieves its properties through proper chemical composition, hot rolling and specific heat treatment. Therefore, high rate of care is necessary when joining this steel into permanent joints – modern steel constructions.
This master’s thesis deals with the problem of weldability of S1100QL steel using gas metal arc welding process. All welded joints have been characterised with following non-destructive and destructive methods: penetrant testing, tensile test, bend test, impact test, hardness testing, macro- and microscopy. Additionally, cold cracking sensitivity test has been done. The master´s thesis has shown that low heat input with correlation of proper preheating and interpass temperatures are necessary for high quality welded joints. Experimental results have also shown that S1100QL steel is not sensitive to cold crack appearance even at low preheating temperatures.
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