DATASHEETOFSTRENGTH工程名称:项目号:版次:设计单位:项目负责:设计:校核:审核:压力管道强度计算书-1-工业及热力管道壁厚计算书1直管壁厚校核1.1计算公式:根据《工业金属管道设计规范》(GB50316-2000)6.2中规定,当直管计算厚度ts小于管子外径Do的1/6时,承受内压直管的计算厚度不应小于式(1)计算的值。设计厚度tsd应按式(2)计算。PYEPDtjtos2(1)Cttssd(2)21CCC(3)式中st—直管计算厚度(mm);P—设计压力(MPa);oD—管子外径(mm);t—在设计温度下材料的许用应力(MPa);jE—焊接接头系数;sdt—直管设计厚度(mm);C—厚度附加量之和(mm);1C—厚度减薄附加量(mm)2C—腐蚀或腐蚀附加量(mm)Y—计算系数压力管道强度计算书-2-设计压力P:P=2σt/(D-2tY)Y=0.4--0Cr18Ni9式中设计温度为常温,一般取50℃,t根据《工业金属管道设计规范》(GB50316-2000)附录A金属管道材料的许用应力表A.0.1进行选取,故20#为130MPa,0Cr18Ni9为128.375MPa。jE取值是根据《压力管道规范-工业管道第2部分:材料》(GB/T20801.2-2006)表A.3,故20#和0Cr18Ni9的取值都为1。Y根据《工业金属管道设计规范》(GB50316-2000)表6.2.1进行选取,故20#和0Cr18Ni9的取值都为0.4。1.2常用低压管道计算厚度设计压力钢管外径管道材质许用应力(50℃情况下)焊接接头系数计算系数计算厚度P(MPa)Do(mm)[σ]t(MPa)EjYts(mm)1.65720#13010.40.351.68920#13010.40.551.610820#13010.40.661.615920#13010.40.97压力管道强度计算书-3-1.3常用高压管道计算厚度设计压力钢管外径管道材质许用应力(50℃情况下)焊接接头系数计算系数计算厚度P(MPa)Do(mm)[σ]t(MPa)EjYts(mm)27.5100Cr18Ni9128.37510.40.9927.5120Cr18Ni9128.37510.41.1827.5220Cr18Ni9128.37510.42.1727.5250Cr18Ni9128.37510.42.4727.5320Cr18Ni9128.37510.43.161.4厚度附加量(1).C1厚度减薄附加量(mm),取钢管允许厚度负偏差。根据《流体输送用不锈钢无缝钢管》(GB/T14976-2002)规定:热轧(挤、扩)钢管壁厚<15mm时,普通级允许厚度负偏差(12.5%δ)高级允许厚度负偏差(12.5%δ);热轧(挤、扩)钢管壁厚≥15mm时,普通级允许厚度负偏差(15%δ)高级允许厚度负偏差(12.5%δ);冷拔(轧)钢管壁厚≤3mm时,普通级允许厚度负偏差(14%δ)高级允许厚度负偏差(10%δ);冷拔(轧)钢管壁厚>3mm时,普通级允许厚度负偏差(10%δ)高级允许厚度负偏差(10%δ)。根据《输送流体用无缝钢管》(GB/T8163-2008)规定:热轧(挤压、扩)钢管外径≤102mm时,允许厚度负偏差(12.5%δ或0.40中较大值);热轧(挤压)钢管外径>102mm时,当壁厚和外径的比值压力管道强度计算书-4-≤0.05时,允许厚度负偏差(15%δ或0.40中较大值)>0.05~0.10时,允许厚度负偏差(12.5%δ或0.40中较大值)>0.10时,允许厚度负偏差(10%δ);冷拔(轧)钢管壁厚≤3mm时,允许厚度负偏差(10%δ或0.15中较大值);冷拔(轧)钢管壁厚>3mm时,允许厚度负偏差(10%δ)。综上所述,考虑到CNG站用钢管基本上为冷拔(轧)钢管,故厚度负偏差应按照上面规定根据钢管材质选择。(2).C2腐蚀附加量(mm),20#钢管的腐蚀裕量参照《钢制对焊管件规范》(SY/T0510-1998)取1.5mm,0Cr18Ni9钢管的腐蚀附加量一般为0mm。1.5常用管道的设计厚度设计压力钢管外径钢管规格公称壁厚管道材质许用应力(50℃情况下)焊接接头系数计算系数计算厚度厚度负偏差腐蚀裕量设计厚度P(MPa)Do(mm)δ(mm)[σ]t(MPa)EjYts(mm)C1(mm)C2(mm)tsd(mm)1.65757×4420#13010.40.350.401.502.251.65757×5520#13010.40.350.501.502.351.68989×5520#13010.40.550.501.502.551.6108108×4.54.520#13010.40.660.451.502.611.6108108×5520#13010.40.660.501.502.661.6159159×5520#13010.40.970.501.502.971.6159159×6620#13010.40.970.601.503.0727.51010×220Cr18Ni9128.37510.40.990.280.001.2727.51212×220Cr18Ni9128.37510.41.180.280.001.4627.52222×3.53.50Cr18Ni9128.37510.42.170.350.002.5227.52222×440Cr18Ni9128.37510.42.170.400.002.5727.52525×440Cr18Ni9128.37510.42.470.400.002.8727.53232×550Cr18Ni9128.37510.43.160.500.003.66钢管的公称壁厚大于设计壁厚,故所选钢管的壁厚符合要求。压力管道强度计算书-5-2弯管壁厚校核2.1计算公式根据《压力管道规范-工业管道第3部分:设计和计算》(GB/T20801.3-2006)6.2规定:内压弯管的计算厚度(位于2处,最危险处)应按式(4)计算:PYIEPDtjtow2(4)当计算弯管的内侧厚度时:2414ooDRDRI(5)当计算弯管的外侧厚度时:2414ooDRDRI(6)式中wt—弯管(内、外侧)的计算厚度(mm);—弯管的转角(度);I—计算系数;R—弯管在管子中心线处的弯曲半径(mm);2.2弯曲半径根据《工业金属管道工程施工及验收规范》(GB50235-97)中规定:高压钢管的弯曲半径大于管子外径的5倍,其他管子的弯曲半径宜大于管子外径的3.5倍。对于一些在工厂内加工的弯管,最小可以压力管道强度计算书-6-使R=1.5Do,而在一般情况下R≥3Do,故在计算中选用R=1.5Do和R=3Do两种情况,因为只要这两种情况下的设计壁厚可以符合要求,其他情况下的设计壁厚就都是符合要求的。压力管道强度计算书-6-2.3常用弯管的设计厚度设计压力钢管外径钢管规格公称壁厚管道材质许用应力(50℃情况下)焊接接头系数计算系数(R=1.5Do内侧)计算系数(R=1.5Do外侧)计算系数(R=3Do内侧)计算系数(R=3Do外侧)计算系数计算厚度(R=1.5Do内侧)计算厚度(R=1.5Do外侧)计算厚度(R=3Do内侧)计算厚度(R=3Do外侧)厚度负偏差腐蚀裕量设计厚度(R=1.5Do内侧)设计厚度(R=1.5Do外侧)设计厚度(R=3Do内侧)设计厚度(R=3Do外侧)P(MPa)Do(mm)δ(mm)[σ]t(MPa)EjIIIIYts(mm)ts(mm)ts(mm)ts(mm)C1(mm)C2(mm)tsd(mm)tsd(mm)tsd(mm)tsd(mm)1.65757×4420#13011.250.8751.10.928571430.40.440.310.380.320.401.502.342.212.282.221.65757×5520#13011.250.8751.10.928571430.40.440.310.380.320.501.502.442.312.382.321.68989×5520#13011.250.8751.10.928571430.40.680.480.600.510.501.502.682.482.602.511.6108108×4.54.520#13011.250.8751.10.928571430.40.830.580.730.610.451.502.782.532.682.561.6108108×5520#13011.250.8751.10.928571430.40.830.580.730.610.501.502.832.582.732.611.6159159×5520#13011.250.8751.10.928571430.41.220.851.070.900.501.503.222.853.072.901.6159159×6620#13011.250.8751.10.928571430.41.220.851.070.900.601.503.322.953.173.0027.51010×220Cr18Ni9128.37511.250.8751.10.928571430.41.210.871.080.920.280.001.491.151.361.2027.51212×220Cr18Ni9128.37511.250.8751.10.928571430.41.451.051.291.110.280.001.731.331.571.3927.52222×3.53.50Cr18Ni9128.37511.250.8751.10.928571430.42.661.922.372.030.350.003.012.272.722.3827.52222×440Cr18Ni9128.37511.250.8751.10.928571430.42.661.922.372.030.400.003.062.322.772.4327.52525×440Cr18Ni9128.37511.250.8751.10.928571430.43.022.182.692.300.400.003.422.583.092.7027.53232×550Cr18Ni9128.37511.250.8751.10.928571430.43.872.793.452.950.500.004.373.293.953.45弯管的公称壁厚大于设计壁厚,故所选壁厚符合要求。