Displaying time (hh:mm:ss) on a chart

Hi everyone, 

I'm currently working on a Power BI project and I ran into a problem. I want a bar chart, with different subjects, and for the bars I want a sum of hours worked on each subject (example: I worked 03:30:00 hours on maintenance and a friend worked 01:00:00 hours on maintenance too, so the bar must show a total of 4:30:00 [hh:mm:ss] for the maintenance subject), taking into consideration that I have different types of subjects, how can I do that?

Here's an example of what I need (on excel):

And here's what I managed to do (though it's not what I want):