Hosted by Shanghai Steel Union Information Technology Co., Ltd., Shanghai Futures Exchange, Ang Iron Iron Association (Guangzhou) Stainless Steel Co., Ltd. Cooperation, Guangdong Shuangxing New Material Group Co., Ltd., Jinyu International Metal Trading Square, Foshan Shui Baobao Import and Export Trade Co., Ltd., Foshan Xishun Metal Technology Co., Ltd., Yangjiang Lianchang Metal Technology Co., Ltd., Sichuan Changxin Pipe Industry Co., Ltd., Guangdong Yifang Pipe Industry Co., Ltd., Guangzhou Hao Metallurgical Equipment Technology Co., Ltd. Sponsored “Chunhui” 2021 (3rd) Stainless Steel Industry Chain Summit on April 20-23, 2021 in Foshan Poly Intercontinent The hotel was held.
On April 22, the stainless steel pipe was officially held at 9 am. At the meeting, the current member of the Shanghai Construction Decoration Materials Association of Expert Committee, “” “Water Supply, Stainless Steel Racing Ratio” Interpretation “Theme Speech.
The use of the use of stainless steel-free bellows with water supply and its applicable range, specifications, materials, connection, requirements, and experimental methods.
First, use the background
Water supply system leaks to make the world that are poor or wealthy cities are deeply trapped, causing expenses including the cost of leak water, including additional other fees, such as lack of water, resulting in finding, processing And save more water.
However, the stainless steel corrugated water pipe can deal with this problem, because the stainless steel corrugated water pipe has corrosion resistance and elasticity, durable, and reduces the number of connections, so it plays an important role in preventing leakage.
The experience of Tokyo, Seoul and Taipei proves that stainless steel is suitable as a material for supplying water, even if it is a large system for large scale. Although the initial cost may be higher than the competitive material, stainless steel has been worth investing in the long life period, and it can bring return on investment every year due to the reduction of maintenance requirements and each gallon processing cost.
Second, the scope of application
This standard applies to the nominal pressure of no more than 1.6 MPa, the nominal size is not more than DN 50, and the intermittent bellows of water, hot water, and drinking water purification is delivered.
Third, the specification model
The interrupt bellows can be divided into specifications such as DN15, DN20, DN25, DN32, DN40, DN50 in nominal dimensions.
1. The raw material of the intermittent bellows should comply with the provisions of GB / T 3280 in a plate number of 022 Cr17Ni12MO2 (S31603), or use stainless steel material above equivalent and equal level.
2, the raw materials should not cause harm to human health, and should not cause any water quality, appearance, taste, smell, etc. when used for transporting drinking water.
The connection of intermodular bellows can be mechanically connected, a calorie connection, a welded connection, a ring-pressed connection, and the like.
1. Appearance: The surface of the intermittent bellows should have no deformation, discoloration, crack and scratches that exceed the wall thickness tolerance.
2, structure and size: intermittent bellows must not have ring welds, and the longitudinal weld should not exceed 1. The two ends of the interrupt bellows should be at right angles with the tube axis, each intermittent bellows, should be set to 8-segment ripple and 9 segment straight tubes, and remain straight. The length of use can be determined based on the on-site construction demand, should be cut from the straight tube.
3, delivery status: After the interrupt bellows are formed, the solution treatment should be carried out, and the acid washing passivation treatment can be carried out using light.
4, withstand voltage performance: interrupt corrugated pipe should perform a pressure-resistant test, the test pressure is 2.5 MPa, should have no rupture, leakage or other defects.
5. Test: Intermittent corrugated pipe should be airtight test, and the test pressure is 0.6 MPa, and there should be no leakage.
6, bending performance: intermittent bellows with a static curved radius R, and bending the bending test in accordance with the specified number of bendings, under water pressure of 0.1 MPa, there is no leakage and other abnormalities.
7, flattening performance: interrupt corrugated pipe should be tested, under external force, the maximum outer diameter of the bellows is slow to 2/3 height, the surface of the bellows should occur without crack or injury.
8. Hardness: The corrugated part of the interrupt bellows should be less than 200 hV.
9, thickness reduction rate: The thickness thinning rate of the variant bellows should be less than 20%.
10, hygiene performance: It is used in places where drinking water, water purification, etc., and intermittent bellows should comply with the provisions of GB / T17219.
Seven, test method
Appearance: The method of visualization should be carried out at a natural scattered light or a non-reverse light-free white light, and the light is not less than 300 lx, and the measurement is 300 mm.
2. Structure: The structure of the interrupted bellows adopts visual measurement, the size of the corresponding accuracy is measured.
3, withstand voltage test: Inject the test sample into the water, the internal air is released, slowly boost to 2.5 MPa, under test pressure, the regulator time is not less than 5 s.
4, airtight test: Intermittent corrugated pipe should be airtight test, and the test pressure is 0.6 MPa, and there should be no leakage.
5, flattening performance: Place the sample in the two flat, the weld should be perpendicular to the compression direction, slowly press to the maximum outer diameter 2 / 3h height of the bellows.
6. Hardness: Take a complete waveform of the solution treatment, along the axis, and measure its Vickers hardness. The peak, middle and wave valley is measured at 4 points, calculating the average of the results of each measurement.
7, wall thickness reduction rate: measured its cross-section thickness, 4 measuring values of the straight tube measurement, and 6 measurement values were taken from the peak measurement position. When measuring, the weld should be avoided and wound along the circumferential direction, and the tube measurement position should be outside the 50 mm molding effect area.
8, hygiene performance: The hygiene performance test of the interrupt bellows should be carried out according to the provisions of GB / T 17219.