I have an 230 VAC Forney arc welder. The spec plate shows "Input amps Max R.L.---32" and "Input amps S.C.-----48". What circuit breaker do I need? Would a 30 amp double pole be enough?

What model number welder do you have?

Does the welder have a cord and plug provided? What amp rating is on the plug?
List all nameplate details.

It is an old Forney Model C-5 welder. Maximum output is 180 amps. It has a 50 amp 230VAC plug. The following is on the label. Model C-5, Pri Volts 230, Freq 60, Phase 1, Volts at max. output--25, Max. open circuit volts----75, Rated duty cycle--20%, Input amps at max.R.L.---32, Input amps S.C.--48, Power Factor at max R.L.---80%, Max Sec. Amps---180. I have had a 40 amp breaker and it worked okay, but I need to change the service panel and I thought that I should put in the proper breaker.

Input amps is relative to the current used to weld, if thin metal then a 30 or 40 will be enough, if there is any chance the unit could be used heavier output amps , then use the 50 amp circuit,

Thanks, That answers my question. I'll probably go with 50 amps to cover all possibilities.