李海宽4月17号日报

焊接钢管：也叫焊管，是用钢板或钢带经过弯曲成型，然后经焊接制成。

按焊缝形式分为直缝焊管和螺旋焊管。

按用途又分为一般焊管、镀锌焊管、吹氧焊管、电线套管、公制焊管、托辊管、深井泵管、汽车用管、变压器管、电焊薄壁管、电焊异型管和螺旋焊管。

一般焊管：一般焊管用来输送低压流体。

用Q195A、Q215A、Q235A钢制造。

也可采用易于焊接的其它软钢制造。

钢管要进行水压、弯曲、压扁等实验，对表面质量有一定要求，通常交货长度为4-10m，常要求定尺（或倍尺）交货。

焊管的规格用公称口径表示（毫米或英寸）公称口径与实际不同，焊管按规定壁厚有普通钢管和加厚钢管两种，钢管按管端形式又分带螺纹和不带螺纹两种，表6-17为焊接钢管尺寸。

表6-17低压流体输送用焊接钢管（根据GB/T3092-93）公称口径外径普通钢管加厚钢管mm in 公称尺寸mm 允许偏差壁厚理论重量kg/m 壁厚理论重量kg/m 公称尺寸mm 允许偏差% 公称尺寸mm 允许偏差% 6 1/8 10.0 +0.50mm -0.50mm 2.00 +12 -15 0.39 2.50 +12 -15 0.46 8 1/4 13.5 2.25 0.62 2.75 0.73 10 3/8 17.0 2.25 0.82 2.75 0.97 15 1/2 21.3 2.75 1.26 3.25 1.45 20 3/4 26.8 2.75 1.63 3.50 2.01 25 1 33.5 3.25 2.42 4.00 2.91 32 11/4 42.3 3.25 3.13 4.00 3.78 40 11/2 48.0 3.50 3.84 4.25 4.58 50 2 60.0 +1% -1% 3.50 4.88 4.50 6.16 65 21/2 75.5 3.75 6.64 4.50 7.88 80 3 88.5 4.00 8.34 4.75 9.81 100 4 114.0 4.00 10.85 5.00 13.44 125 5 140.0 4.00 13.42 5.50 18.24 150 6 165.0 4.50 17.81 5.50 21.63 随着焊接钢管技术提高提高和加工简便，现在焊接管代替部分无缝管，焊接钢管已能生产219mm（8寸）以上。

镀锌钢管：为提高钢管的耐腐蚀性能，对一般钢管（黑管）进行镀锌。

镀锌钢管分热镀锌和电钢锌两种，热镀锌镀锌层厚，电镀锌成本低。

吹氧焊管：用作炼钢吹氧用管，一般用小口径的焊接钢管，规格由3/8寸-2寸八种。

用08、10、15、20或Q195-Q235钢带制成。

为防蚀，有的进行渗铝处理。

电线套管：也是普通碳素钢电焊钢管，用在混凝土及各种结构配电工程，常用的公称直径从13-76mm。

电线套套管壁较薄，大多进行涂层或镀锌后使用，要求进行冷弯试验。

公制焊管：规格用无缝管形式，用外径*壁厚毫米表示的焊接钢管，用普通碳素钢、优质碳素钢或普能低合金钢的热带、冷带焊接，或用热带焊接后再经冷拨方法制成。

公制焊管分普能和薄壁、普通用作结构件，如传动轴，或输送流体，薄壁用来生产家具、灯具等，要保证钢管强度和弯曲试验。

托辊管：用于带式输送机托辊电焊钢管，一般用Q215、Q235A、B钢及20钢制造，直径63.5-219.0mm。

对管弯曲度、端面要与中心线垂直、椭圆度有一定要求，一般进行水压和压扁试验。

变压器管：用于制造变压器散热管和其它热交换器，采用普通碳素钢制造，要求进行压扁、扩口、弯曲、液压试验。

钢管以定尺或倍尺交货，对钢管弯曲度有一定要求。

异型管：由普通碳结结构钢及16Mn等钢带焊制的方形管、矩形管、帽形管、空胶钢门窗用钢管，主要用作农机构件、钢窗门等。

电焊薄壁管：主要用来制作家具、玩具、灯具等。

近年来不锈钢带制作的薄壁管应用很广，高级家具、装饰、栏栅等。

螺旋焊管：是将低碳碳素结构钢或低合金结构钢钢带按一定的螺旋线的角度（叫成型角）卷成管坯，然后将管缝焊接起来制成，它可以用较窄的带钢生产大直径的钢管。

螺旋焊管主要用于石油、天然气的输送管线，其规格用外径*壁厚表示。

螺旋焊管有单面焊的和双面焊的，焊管应保证水压试验、焊缝的抗拉强度和冷弯性能要符合规定。

直缝埋弧焊管LSAW (Longitudinally Welded SAW Pipe)双缝埋弧焊钢管DSAW（Double submerged arc welded ）Welded pipe (pipe manufactured with a weld) is a tubular product made out of flat plates, known as skelp, that are formed, bent and prepared for welding. The most popular process for large diameter pipe uses a longitudinal seam weld. Double submerged arc welded (DSAW) pipe is welded pipe whose longitudinal butt joint is welded in at least two passes, one of which is on the inside of the pipe; the welds are made by heating with an electric arc between the bare metal electrode. Pressure is not used. Filler metal for the welds is obtained from the electrodes. For diameters above 36 inches, double seam welded pipe is specified as an alternative in API 5L. This has two longitudinal seams 180° apart, formed by the SAW process. Finished pipes are normally 40 feet (12 m) and occasionally 60 feet (18 m) long, depending on the capacity of the pipe mill and the ease of transport to the pipeline.螺旋管Spiral Welded PipeAs an alternative process, spiral weld construction allows large diameter pipe to be produced from narrower plates or skelp. The defects that occur in spiral welded pipe are mainly those associated with the SAW weld, and are similar in nature to those for longitudinally welded SAW pipe. An additional problem with early spiral welded pipe was poor dimensional accuracy, particularly out of roundness at the pipe ends. This led to problems of poor fit-up during field girth welding. Spiral linepipe gained a poor reputation in some companies as a result of these early experiences, and it was considered suitable only for low pressure applications such as water pipe. However, modern spiral linepipe from a premium quality supplier is of a quality equivalent to straight seam welded pipe, and it has been used extensively in Canada and Europe for high pressure gas pipelines in grades up to API X70.无缝管(SMLS)Seamless PipePlug MillThis process is used to make larger sizes of seamless pipe, typically 6 to 16 inches (150 to 400 mm) diameter. An ingot of steel weighing up to two tons is heated to 2,370 °F (1,300 °C) and pierced. The hole in the hollow shell is enlarged on a rotary elongator, resulting in a short thick-walled tube known as a bloom. An internal plug approximately the same diameter as the finished diameter of the pipe is then forced through the bloom. The bloom containing the plug is then passed between the rolls of the plug mill. Rotation of the rolls reduces the wall thickness. The tube is rotated through 90° for each pass through the plug mill to ensure roundness. The tube is then passed through a reeling mill and reducing mill to even out the wall thickness and produce the finished dimensions. The tube is then cut to length before heat treatment, final straightening, inspection, and hydrostatic testing.Mandrel MillThis process is used to make smaller sizes of seamless pipe, typically 1 to 6 inches (25 to 150 mm) diameter. The ingot of steel is heated to 2,370 °F (1,300 °C) and pierced. A mandrel isinserted into the tube and the assembly is passed through a rolling (mandrel) mill. Unlike the plug mill, the mandrel mill reduces wall thickness continuously with a series of pairs of curved rollers set at 90° angles to each other. After reheating, the pipe is passed through a multi -stand stretch-reducing mill to reduce the diameter to the finished diameter. The pipe is then cut to length before heat treatment, final straightening, inspection, and hydrostatic testing. ExtrusionThis process is used for small diameter tubes only. The bar stock is cut to length and heated to 2,280 °F (1,250 °C) before being sized and descaled. The billet is then extruded through a steel die. After extrusion, the final tube dimensions and surface quality are obtained with a multi-stand reducing mill.高频焊管Electric Resistance Welded (ERW) and High Frequency Induction (HFI) Welded Pipe Originally this type of pipe, which contains a solid phase butt weld, was produced using resistance heating to make the longitudinal weld (ERW), but most pipe mills now use high frequency induction heating (HFI) for better control and consistency. However, the product is still often referred to as ERW pipe, even though the weld may have been produced by the HFI process.The defects that can occur in ERW/HFI pipe are those associated with strip production, such as laminations and defects at the narrow weld line. Lack of fusion due to insufficient heat and pressure is the principal defect, although hook cracks can also form due to realignment of non metallic inclusions at the weld interface. Because the weld line is not visible after trimming, and the nature of the solid phase welding process, considerable lengths of weld with poor fusion can be produced if the welding parameters fall outside the set limits. In addition, early ERW pipe was subject to pressure reversals, a problem that results in failure in service at a lower stress than that seen in the pre-service pressure test. This problem is caused by crack growth during the pressure test hold period, which in the case of early ERW pipe was due to a combination of low weld line toughness and lack of fusion defects.A Note About the Lack of Fusion in ERW WeldAs a result of these early problems, ERW pipe was generally regarded as a second-grade pipe suitable only for low pressure applications. However, prompted by a shortage of seamless pipe and the lower cost of ERW pipe, suppliers and end users directed a major effort toward improving the pipe mill quality in the 1980s. In particular, accurate tracking of the weld line by the automatic ultrasonic inspection equipment was found to be crucial, since the weld line can rotate slightly as the pipe leaves the welding station. In addition, the standard of heat treatment of the weld line, which is necessary to ensure good toughness, was found to be important and some specifications call for local weld line heat treatment using induction coils followed by full body normalizing of the whole pipe in a furnace. As a result of these improvements, modern ERW/HFI pipe has much better performance than the traditional product and has been accepted by a number of operators for high pressure gas transmission. 英制管壁厚的表示：Sch.20----全称：Schedule 20Sch.10s--带s的系列为不锈钢专用，碳钢不用。