I have a Winchester 52 pre A model with a cracked lug.They are famous for this but is there any solution to fix the receiver.
Could it be Tig welded and built up ?Is there anybody who has done this.

Here is an image of the receiver and cracked lug with an red arrow pointing it out.

not hardto weld , but would have to be retempered

How about micro-tig would you still have to re-temper?

Why do they crack ? Is that a case hardened receiver ? You should always temper after welding . Tempering may be only about 500 F.

You can read about the problem here at this link

http://www.rimfirecentral.com/...wthread.php?t=326703

I've never seen one of these before but if I was given the task of fixing it, the photo above and those in the link GaryMD has provided look to show the lug on the bolt collar is reasonably substantial and could be cut back a bit to allow the cracked lockup lug to be extended forward to provide a much stronger design, either an extra lug piece pinned in place and welded or just the original welded back in place and then built forward, shaped and hardened. I would go with pinning which in itself using a hardened pin or one that will harden when welding will provide support off the action sidewall.

The original lug which is seems notoriously prone to cracking is quite visibly a poorly engineered design.

even a laser weld will take away some temper

I've spent so many years finding why parts break !You'd think they would learn but they don't .Many failures are just poor basic engineering design ,sharp corners etc.

The new weld can introduce new problems ,even a small laser weld. Just like EDM - you better temper after EDM even though the damage is 0.001" thick !