G 高压锅炉用内螺纹无缝钢管 Multi-rifled seamless steel tubes for high-pressure boiler
高压锅炉用内螺纹无缝钢管国家标准
Multi-rifled seamless steel tubes for high-pressure boiler
标准号
GB/T 20409-2006
主要生产牌号:
20G 20MnG 25MnG 12CrMoG 15CrMoG SA-210C SA-210A1
SA-213T2 SA-213 T12等
“A” 型齿型内螺纹管的部分尺寸规格及螺纹参数尊龙官网
内螺纹管的尺寸及螺纹参数允许偏差
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A
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外径:外径≤38.1 mm
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±0.15 mm
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—
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38.1<外径<50.8 mm
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±0.20 mm
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50.8mm≤外径<63.5 mm
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±0.25 mm
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外径≥63.5 mm
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±0.30 mm
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B
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外径:外径≤38.1 mm
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—
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±0.15 mm
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38.1<外径<50.8 mm
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±0.20 mm
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50.8≤外径<63.5 mm
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±0.25 mm
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外径≥63.5 mm
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±0.30 mm
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C
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螺纹根部内径:外径-(1.11×最小壁厚×2)
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|
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外径≤38.1mm
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±0.15 mm
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±0.15 mm
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38.1<外径<50.8 mm
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±0.20 mm
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±0.20 mm
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50.8≤外径<63.5 mm
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±0.25 mm
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±0.25 mm
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外径≥63.5 mm
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±0.30 mm
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±0.30 mm
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E
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最小内径
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负偏差为0
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负偏差为0
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F
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最小壁厚
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22%
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22%
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0
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0
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G
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螺纹头数
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—
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—
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I
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螺纹顶宽(周向):
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—
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—
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J a
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螺纹高度:外径≤38.1 mm
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±0.3 mm
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±0.18 mm
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38.1<外径<50.8 mm
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±0.20 mm
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50.8≤外径<63.5 mm
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±0.23 mm
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外径≥63.5 mm
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±0.28 mm
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K
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螺纹侧边角度
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±15°
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±15°
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O
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螺纹根部圆角半径
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—
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—
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M
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螺纹节距
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±3.2 mm
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±3.2 mm
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N
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螺纹导程
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±3.2 mm×螺纹头数
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±3.2 mm×螺纹头数
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Q b
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螺旋升角
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额定值
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额定值
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T
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螺纹顶宽(轴向)
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±1.3 mm
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±1.3 mm
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U
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螺纹顶部(轴向)槽宽
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—
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--
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a 对“B”型齿型,任何一个螺纹高度的最大偏差可超出表中规定的允许偏差值,但不应超出允许偏差0.08 mm,且所有螺纹的平均高度应符合所给出的偏差范围。
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