Pressure does not appreciably affect temperature in liquids.
Process conditions and pump/motor heat dissipation are the significant factors you need to look at for temperature.
If you're at any significant temperature, don't just take room temperature to design with. For low alloy steel along the lines of 4130/4140, we usually use a 90% yield strength derate for 300°F.
Any hard data you find will have a decent variance from lot to lot. One mill run may derate 92% at...
