| China's implementation of standard strand |
1 Definition: The preparation of a good wire required on the machine made a multi-stranded twisted roots that strand.
Types and uses: steel wire strand according to different preparation and different uses can be divided into: galvanized steel wire, prestressed concrete strand, aluminum-clad steel wire.
① galvanized steel wire: Galvanized steel wire is mainly used for hangers, hanging, communication cables, overhead power lines and fixed objects, tethered, etc.
a, galvanized steel wire according to the cross-section structure can be divided into three types: 13,17,119;
b, galvanized steel wire according to the different nominal tensile strength, galvanized steel strand can be divided into 1175,1270,1370,1470 and 1570 (N/mm2), a total of five;
c, based on zinc galvanized steel wire strand of different thickness, galvanized steel strand can be divided into a (thick) level, B (thick) level, C (thin) level.
② prestressed concrete strand: prestressed steel wire strand is twisted into a circular cross-section made of prestressed concrete structures, such as use of the strand rock anchor.
a, according to the structure of prestressed steel strand twisting into 12,13,17 three;
b, according to the stress relaxation performance is divided into grade Ⅰ (normal relaxation level), Ⅱ grade (low relaxation grade).
③ aluminum-clad steel wire: aluminum-clad steel wire is mainly used for overhead power lines and ground wire and electrified line catenary.
According to the structure can be divided into four categories: 13,17,119,137
2 Specifications and appearance quality
(1) twisting the surface of galvanized steel wire strand coated layer should be uniform, continuous zinc, without spot scars, defects such as cracks and lack of plating. Galvanized steel wire strands within the wire should be tight
(2) shall not be prestressed strand surface with lubricant, grease and other lower strand and concrete bond strength of the material. Strand surface to allow a slight rust, but not as visible rust Ma Hang.
(3) aluminum-clad steel wire surface should be smooth, the phenomenon does not allow any exposed steel. Strand should be evenly close, there should be no shortage of wire, broken wire, loose stock, damaged and so on, should not be loose after the cut.
3 Chemical composition test
(1) strand of the chemical composition is generally not provided for. As for the production of steel of various specifications and grades of wire rod have been testing the chemical composition, and in line with national standards.
(2) single-strand wire galvanized zinc coating weight requirements are.
4 Physical performance test
(1) mechanical properties.
① galvanized steel strand and aluminum clad steel strand mechanical properties are divided into two parts, namely
a, strand of wire mechanical properties. Key indicators are: tensile strength, elongation, reverse 360 number;
b, the mechanical properties of strand. Breaking the main indicators of overall strength. These two parts should be in line with GB1200-88, YB/T5400-93, YB/T123-1997, YB/T124-1997 specified value.
② mechanical properties of prestressed concrete strand is: maximum load, elongation, yield load, relaxation rate. The test results should be consistent with the values provided GB/T5224-1995.
③ tensile testing according to GB228-87 (metal tensile test method); torsion test according to GB239-84 (metal torsion test method). Relaxation tests according to GB10120-88 (metal stress relaxation test method).
(2) electrical properties: aluminum-clad steel strand wires should be detected as a DC resistance 20 ℃. The results should be consistent with the values provided GB/T124-1997.
5 packaging in general all kinds of steel wire into a disk should be delivered. Under the agreement may increase moisture-proof paper, linen, woven cloth and other complementary packaging.
6 main production plants and export countries and regions
(1) China's main export origin of Liaoning, Tianjin, Shanghai, Jiangsu, Shandong, Sichuan and other provinces and cities of iron and steel enterprises. Mainly exported to Japan, Australia, Singapore, the Philippines and other countries. Export quality and stability.
(2) China, mainly from South Korea, Spain, Germany and other countries imported prestressing strand. Imports of prestressed steel strand relaxation rate targets have been found not qualified.
7. Common standards
(1) GB/T5224-1995 prestressed concrete strand
(2) YB/T5004-1993 galvanized steel strand
(3) YB/T098-1997 Galvanized strand cable
(4) ASTMA416-1996 prestressed concrete wire strand with a standard uncoated seven technical conditions
(5) BS5896-1980 high-strength prestressed concrete steel wire and strand
(6) YB/T2278-1991 aluminum-clad steel wire and aluminum-clad steel core Catenary
(7) AS1222.1-1992 and overhead bare conductor strand
(8) AS3607-1989 wire - bare overhead lines, ACSR and steel core aluminum stranded wire
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