HOT WATER HEATER

摘要

PROBLEM TO BE SOLVED: To enhance the dimensional accuracy of a flow passage and the durability of the flow passage by using a brass-made member which contains Zn such that the apparent Zn content falls in a specific range is terms of % by weight, contains a specific range rate of Sn and has a crystal structure whose particle size is not greater than a specific means particle size as a constitutional member of the flow passage. SOLUTION: A header 7 and an elbow 24 are molded and constituted by forging a brass- made member which contains Zn such that an apparent Zn content is 37-46 wt.%, contains 0.5-7% of Sn and has a crystal structure having a mean crystal particle size of not greater than 20μm. In this crystal structure, the cutting resistance index with the free cutting brass- made bar which follows Japanese Industrial Standard JIS C-3604 set as a standard becomes not less than 80. Furthermore, in a dezincification corrosion test which follows the technical standard JBMA T-303 of the Japan Brass Makers Association, in case the direction of the dezincification infiltration depth is ion parallel with the working direction, the corrosion resistance of the maximum dezincification depth of 100μm is met, while in case the direction of the dezincification infiltration depth is perpendicular to the working direction, the corrosion resistance of the maximum dezincification depth of 70μm is met. That is, the high temperature corrosion resistance, the dezincification corrosion resistance and the cutting ability of the water passage constituting member can be enhanced.