if your 3 phase is 110v from phase to neutral, then you will have about 200v between phases.

My welding machines are biphase I mean they only use two phase wires Each Phase votlage 220V thus effetive biphase voltage 400V this biphase is fed to a step down transformer for the purpose of stepping down to 110V this is the voltage I have got to swtich.

Note that your circuit has no snubbers - fine if you are only switching resistive loads. Also the snubbers protect the devices against high voltage spikes. I would suggest you review the datasheets for the opto and triac for information regarding this. I learnt the hard way!

The circuit that I posted was just a part of the actual circuit the real circuit has snubbers.

I've never come across a 4N40 before!
Looks like 4N40 has become obselete.

Regards,
Prahlad Purohit