You should wear the sunglasses when you look at the sun, instead of the welding mask which could be used to avoid the light radiation. If you do not wear the sunglasses which lenses will protect your eyes from the uv rays, your eyes will be damaged. You need to protect the eyes carefully which are the very important parts for your whole body.
Yes, you can. It won't cause damage if you look at the sun with welding mask.
To be more accurate, you must wear a welding mask or goggle to look at the sun, otherwise you will have a permanent blind spot in the middle of your view field. You can also see the projected image of the sun through a pinhole on a posterboard.
I experienced looking at the sun when I wear welding mask in 2008. I remembered the eclipse of the sun occurred at that day. I would be blind when I directly watched the sun without goggles or something else. Hence I borrowed a welding mask and saw the solar eclipse. So you can look at the sun when you wear a welding mask.