In the final thesis there is analyzed of chrome-molybdenum steel (5%Cr-0,5%Mo) welded joints strength properties dependence on thermal treatment after welding procedures investigation material. Welded joints ultimate strength and impact strength were determined, changing heat treatment after welding temperatures and exposure time. Heat treatment temperature and time parameter was used to systemize investigation. Received results showed that when performing heat treatment after Cr-Mo steel (5%Cr-0,5%Mo) welding, increasing temperature and time parameter values, welded joints strength characteristics values go down. Welded joints after heat treatment strength properties dependence on temperature and time parameter were determined, increasing this parameter, ultimate strength and impact strength values go down.

The aim of this diploma thesis is to compare mechanical properties of welded joints on tubes from 32x2 mm. Tubes are made from 25CrMo4 steel, which is used for production of racing kart chassis. The steel has a tensile strength of Rm = 800 MPa and up to 1200 MPa after refinement. For welding of samples are used technologies MAG and TIG.