我想知道，第幾分鐘的英文該如何表達?

譬如生產流程，焊接會在第五分鐘進行。

是 Welding will proceed at fifth minute or at five minutes?

Soldering/ welding process will be automatically and periodically carried out at the very start of the fifth minute of the hour, i.e. 00:05, 01:05, 02:05, etc., around the clock.Michael is going to play first fiddle/ violin.

Welding will begin at the fifth minute of the production.

or "Welding will begin five minutes into the production."