The installation quality of thin-walled brass pipe is related to many factors, such as the quality of the material used, the quality of the brazing, the quality of the bend, and the overall skill of the construction personnel. As well as the brass tube support hanger and temperature changes caused by expansion damage.
Thin-walled brass pipe material, base material to reasonable composition, pipe wall thickness uniform, under test pressure without holes, no leakage, in line with national standards, and passed the sampling inspection. Because TPZ contains 0.015%-0.04% phosphorus, the crime does not contain phosphorus, and the oxygen content of the crime is 6 times that of TP2. The phosphorus content is conducive to the flow of the solder and makes the weld firm. The phosphorus also reduces the oxygen content of the weld and enhances the corrosion resistance of the brazing joint, while the high oxygen content is not conducive to the corrosion resistance of the brazing joint. Therefore, TP2 phosphorus deoxidized copper was used. Use socket type brazing connection. Brazing connections are divided into hard brazing and soft brazing connections. Hard brazing connection is safer, its connection strength is high, tightness is good, suitable for any specifications of brass pipe connection, is a non-removable connection. The embedded brass pipe shall be rigidly brazed. Non-embedded brass pipe diameter, ≤DN25 branch pipe can be connected by soft brazing.
Bending pipe is an effective method to reduce the welding times and eliminate the stress caused by pipeline expansion, but attention should be paid to the thinning of the wall thickness after bending pipe. The wall thickness of elbow pipe should be increased by a certain thickness than that of straight pipe. The value should be determined according to the process and actual situation. It is difficult to implement butt fusion welding for the connection of thin-walled brass pipe, and the simple method is lap brazing. It is recommended to adopt conventional socket type brass pipe fitting. During brazing, the operator adds filler metal from the outside of the pipe to fill the gap to form the brazing joint. Due to high melting point solder, must adopt a oxygen acetylene flame or oxygen propane flame as a heat source, to meet the needs of brazing temperature and thermal power, especially when large diameter brass tube brazing, needs to be equipped with two gas welding, heating by two operators at the same time, to control the heating temperature and the joint ring joint and the length of the direction of temperature uniformity, In order to make the melting solder evenly fill the brazing seam, ensure the quality of brazing. Compared with other metal pipes, its weldability is better, and the quality of brazing is a more important factor in the quality of installation. The composition of the filler metal is suitable for the base metal, and the melting point is lower than that of the base metal. It is recommended to use the low silver copper phosphorus filler metal containing 5% silver with the melting point above 640℃.
The copper surface oxide will prevent the atoms of the solder from contacting the brass tube directly, so that the brazing liquid solder will not wet the copper surface. The surface oxygenates, including the oxygenates generated during brazing, must be removed. Insert the brass tube into the fitting, insert to the bottom and rotate properly. To maintain even clearance. The joint will be uniformly heated by fire melting or electric heating. Until the brazing temperature, contact with filler metals are heated to high temperature, the joint to determine tapping temperature, if the solder is not melting, said had not reached the junction temperature brazing temperature, to be continued to heating of joint, if the solder melts, quickly said tapping temperature has reached the brazing temperature, can continue to joint heating, in order to keep the temperature of the joint above the brazing temperature, The filler metal is added to the gap of the joint, and the heat of the joint is used to melt the filler metal into the gap until the brazing joint is filled. Do not use flame to melt the filler metal directly on the surface of the gap. Remove the heat source to stop heating, so that the joint in a static state of cooling crystallization, the brazing joint residue clean up, when necessary, can brush varnish protection.
In the construction, because the brass pipe has good flexibility, in the handling and installation process should be handled with care. No squishing, no weight on top.
