SS 17-1996 适用于BS21管道螺纹的钢管规范

标准号：SS 17-1996
中文标准名称：适用于BS21管道螺纹的钢管规范
英文标准名称：SPECIFICATION FOR Steel Tubes Suitable For Screwing To BS 21 Pipe Threads
发布日期：1996/1/1 12:00:00
实施日期：1999/12/31 12:00:00
适用范围：1.1 The Singapore Standard applies to welded and seamless, screwed and socketed steel tubes and to plain end steel tubes suitable for screwing to BS 21 pipe threads of nominal size DN 8 to DN 150 mm in three series of thicknesses, designated Light, Medium and Heavy.1.2 Definitions. For the purpose of this standard the following definitions apply:1.2.1 Black tube. Tube as manufactured, but without any subsequent surface treatment.1.2.2 Extra length of screwed and socketed tube. The length of the tube exclusive of the socket.1.2.3 Final load. Load imposed on the test piece at the moment of fracture.1.2.4 Gauge length. Length of the cylindrical or prismatic portion of the test piece on which elongation is measured at any moment during the test. In particular, a distinction should be made between the following:(a) original gauge length (L0) - gauge length before the test piece is strained, and(b) final gauge length (Lu) - gauge length after the test piece has been fractured and the fractured parts have been carefully fitted back together so that their axes lie in a straight line.1.2.5 Length of screwed and socketed tube. The overall length of the tube when one socket has been fitted.1.2.6 Load at yield point. Load at which the elongation of the test piece first increases without increase of load or with decrease of load.1.2.7 Maximum load. The greatest load which the test piece withstands during the test.1.2.8 Nominal size (DN). A numerical designation of size which is common to all components in a piping system other than components designated by outside diameters or thread size. It is a convenient round number for reference purposes and is only loosely related to manufacturing dimensions. Nominal size is designated by the letters DN followed by a number. This definition is identical to ISO 6708.Note. It should be noted that not all piping components are designated by nominal size (e.g. Steel tubes are designated and ordered by outside diameters and thicknesses). The nominal size, DN cannot be subject to measurement and shall not be used for purposes of calculations.1.2.9 Percentage elongation after fracture (A). Permanent elongation of the gauge length after fracture (Lu - L0), expressed as a percentage of the original gauge length (L0) (see Table 1).1.2.10 Socket. The screwed coupling utilised in joining the tubes together. The term 'socket' is synonymous with the term 'coupler'.1.2.11 Stress. Load at any moment during the test divided by the original cross-sectional area (S0) of the test piece.1.2.12 Tensile strength (Rm). Maximum load divided by the original cross-sectional area (S0) of the test piece, i.e. stress corresponding to the maximum load.1.2.13 Tube. A long, hollow, open-ended object of circular cross section. The term 'tube' is synonymous with the term 'pipe'.1.2.14 Yield stress (Re). When the metallic material is stressed beyond the elastic limit where plastic deformation occurs without any further increase in load. A distinction is made between the Upper Yield Point and the Lower Yield Point -(a) Upper yield stress (ReH) : Stress corresponding to the highest load when the first decrease in load is observed (see designation no. '23' in Figure 1(c)).(b) Lower yield stress (ReL) : Stress corresponding to the lowest load subsequently observed, ignoring any transient effects (see designation no. '24' in Figure 1 (c))1.3 Symbols And Designations. Symbols and corresponding designations are given in Table 1.1.3.1 Tubes. The tubes covered by this standard shall be designated by their nominal sizes (DN) and shall be further classified as 'Light', 'Medium' and 'Heavy' depending on the wall thickness given in Tables 4, 5 and 6.1.3.2 Sockets and backnuts. Sockets and backnuts shall be designated by the respective nominal size (DN) of the tube for which they are intended.