Copper and ferrous alloys don't play together nicely. Copper has very low solubility in iron and tends to crack during solidification or when subjected to bending. You may be able to braze that combination, but a fusion weld, not likely to pass a standard guided bend test as required by ASME Section IX or AWS B2.1 or NAVSEA TP248.
ishtechmech,
Since you have not bothered to reply, take gtaw's advice. Brazing can be done or use mechanical connection. A fusion weld could be made with extreme difficulty; however, based on your question, you would no way be able to qualify such a weld.