TUBE PRODUCING METHOD, HEAT EXCHANGING TUBE PRODUCED BY THE METHOD, AND HEAT EXCHANGER USING THE TUBE

摘要

A method of producing a tube which has a tube body portion constituting an outer hull of flow passages, and flow passage dividers for dividing the flow passages, comprising a roll forming process to form the tube, a cutting process to cut the tube to a predetermined length after the roll forming process, and a brazing process to braze the tube contact portions of the flow passage dividers to the inner surface of the tube body portion after the cutting process. The cutting process forms a slit in the tube, and so as to concentrate a stress on the slit, thereby to cut the tube starting from the slit. The slit is formed in only the tube body portion between the tube body portion and the flow passage dividers or formed ranging from the tube body portion to the tube contact portions of the flow passage dividers.