Look up forking by frank they make fork tubes.
Your bike has a cast metal neck and most welders don't want to touch that and if they don;t have a gig you might not get a straigh line when welding back together. So if you cut the frame tube you will be back to far to get the right rack.
Please add your state and model of bike you have. Click user CP @ top of page and then far left click edit signature. Thanks