For your particular situation welding/grinding might be your only option. However you really have to be careful when welding as the high heat can cause some porcelain damage. One thing to check into is make sure it is older than 10 years old. If it is relatively now it might be a warranty claim.
In most cases SS bolts, nuts, and washers are an easier fix when sockets fall off and etc.
If that doesn't work then some skilled and strategic welding might work if it is something rare or just worth salvaging for your own personal reasons.
If it is just a black kettle and there is a used market in your area it might actually be worth checking into finding a cheap replacement. It just might be cheaper/easier than taking it to a local welder to repair.
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