What is the allowable error of the standard wall thickness of malleable steel pipe fittings?
Time of issue: 2015-09--28
Malleable cast iron pipe fittings are produced according to GB/T3287-2011 "Malgeable cast iron pipe fittings".
The GB/T 3287-2011 standard is the second Chinese national standard set in July 2009. When the standard was revised, the international standard ISO49: 1994 "Moldable Iron Pipe Fittings with ISO 7-1 Thread" and the European Standard EN 10242: 1994/A2: 2003 "Malgeable Iron Threaded Pipe Fittings" were adopted, which are equivalent to the above two advanced foreign standards.
1. The mechanical properties of the pipe fittings are tensile strength ≥330MPa; elongation ≥8%, which is better than the malleable cast iron of the KTH300-06 grade specified in GB/T9440-2010 "Moldable Iron Castings".
2. The structural dimensions of the pipe fittings conform to the provisions of Appendix A in the GB/T3287-2011 standard, and are consistent with the dimensions stipulated in the ISO49:1994 and EN 10242:1994/A2:2003 standards.
3. The thread of the pipe fitting adopts GB/T7306.1-2000 "55° Sealing Pipe Thread Part 1: Cylindrical Internal Thread and Conical External Thread" and GB/T7306.2-2000 "55° Sealing Pipe Thread Part 2: Conical Internal Threads and Tapered External Threads". It corresponds to the European Community pipe thread standards EN10226-1: 2004 (E) and EN10226-2: 2005 (E). It is the same as the pipe thread profile, size, tolerance and code specified in the international standard ISO7-1:1994. According to the national standards collected at present, all major industrial countries in the world except the United States, the European Community and most countries in the world have adopted the pipe thread standards stipulated by ISO7-1. Therefore, the threads specified in GB/T7306 are consistent with international standards, and can also be smoothly matched with the pipe threads of most countries in the world.
4. The hot-dip galvanized layer of the pipe fittings conforms to the requirements of GB/T3287-2011, ISO49:1994, EN10242:1994/A2:2003 and other standards. The quality of the surface zinc layer is not less than 500g/m2, the average thickness is 70μm, and the average thickness of individual samples is not less than 450g/m2, and the average thickness is 63μm.