Since I'll assume the part already broke on you at the crack and you're still here to post, we can guess it's ok if the part breaks again in future. Gluing the two halves with silver solder or brazing (anything you will think is high strength) will be the most easy thing to do. Flux galore to get a good clean sticking surfaces and chances are the part might even be stronger than before. And if and when it breaks again you can glue it back together once more.
The cut out gorge on the underside provided the sharp angle gash to start the fracture. A tiny radius would have saved the world. Permanent grease on all the rubbing surfaces would have helped. Oh well. With the brazing you'll get that sharp angle relief.
File off the little gobs of excess metal and you're done. The strength of this repair will outdo anything you can achieve with base metal melting repair welds. Whether you get your heat from an open flame or from a TIG arc does not matter much to me - you're just dealing with iron and you don't need the super neutral gas atmosphere you can get on TIG, also, you can't beat the practicality of an open flame - you don't need to worry about the ground connection.
We've wasted more time typing than actually working. A lazy day.
