The welder has 4 wires black,white,red and green. The dryer plug is 3 wire. The dryer receptacle is black, red,and white.please help!!

The dryer is likely 30 amps, sounds like the Welder needs 50 Amps. The wiring would be too small.
A Permanent outlet should be installed with # 6's for your hots, and # 10 for ground.
If this was a one time need for a welder, I might use my Range wiring and a receptacle that fits welder, then restore when done. Or a Temporary box at the panel. Location is the Key.

Check the tag on the welder make sure it is not 3 phase.
Your house is single phase power.