Hi Penut,
Elmdon Metals Birmingham tel:0121 781 0999 fax: 0121 781 0909 ask for Phil Matts.
You may want to consider T45 which does not need normalising after welding you will get more or less what ever guage you require he convinced me on the benifits of T45 against 4130 use an A35 tig rod for welding the T45. Sam