管道预制加工按现场审查确认的管段预制图进行

2023年02月11日20:45:22 0 652

管道预制按现场审核确认的管段预制图进行

（1） 4. 管道预制

4.1管道预制应按预制图进行，并应符合下列要求：

4.1.1管道预制按现场审核确认的管段预制图进行。在预制图上标明现场焊接位置及调整余量；

4.1.2现场组焊的焊缝应便于焊接和检验。

4.2管道预制过程中，应对每道工序的标识进行检查，并移植标识。

4.3管子切割及坡口加工

4.4弯曲度超过允许偏差的钢管，应在加工前进行矫直。碳钢管可冷调或热调，不锈钢管应冷调。

4.5钢管的冷调应在常温下进行。公称直径不大于50mm的管子，用调直机调直，其模具与钢管外径一致。

4.6碳钢管热调时，应将钢管弯曲部分加热至800-1000℃，然后放在平台上反复轧制，使其平直。也可采用火焰矫正法。

钢管预制尺寸按图7加工。切割时应符合下列要求：

4.7.1不锈钢管应采用机械法或等离子法切割

4.7.2碳钢管可采用火焰切割，影响焊接质量的表层必须清除。

4.8钢管焊接坡口加工应符合下列要求：

4.8.1碳钢管应采用机械加工或火焰加工

4.8.2不锈钢管应采用机械方法加工。如果管子切割必须使用专用砂轮或不锈钢砂轮。

4.8.3钢管采用火焰或等离子加工时，必须清除影响焊接质量的表层。

4.9当焊接坡口两侧壁厚差大于下列值时，应按要求减薄。

4.9.1管道内壁差0.5mm或外壁差2mm；

4.9.2. SHB、SHC管道内壁差1mm或外壁差2mm；

4.9.3. 其他管道外壁差3mm。

4.10坡口质量应符合下列要求：

4.10.1表面应光滑，无裂纹、双层皮、毛刺、凹凸颈；

4.10.2清除切割表面的熔渣、氧化铁和铁屑；

4.10.3端面倾斜偏差为管子外径的1%，但不得超过2mm；

4.10.4坡口尺寸和角度应符合要求。

The pipe prefabrication shall be carried out according to the pipe segment prefabrication drawing reviewed and confirmed on site

（1） 4. Pipe prefabrication

4.1 pipe prefabrication shall be carried out according to the prefabrication drawing and meet the following requirements:

4.1.1 the pipe prefabrication shall be carried out according to the pipe segment prefabrication drawing reviewed and confirmed on site. The site welding position and adjustment margin shall be marked on the prefabrication drawing;

4.1.2 the weld of field assembly welding shall be convenient for welding and inspection.

4.2 in the process of pipeline prefabrication, the marks of each process shall be checked, and the marks shall be transplanted.

4.3 pipe cutting and groove processing

4.4 the steel pipe whose bending degree exceeds the allowable deviation shall be straightened before processing. Carbon steel pipe can be adjusted by cold or heat, stainless steel pipe should be adjusted by cold.

4.5 the cold adjustment of steel pipe shall be carried out under normal temperature. The pipe with nominal diameter not more than 50 mm shall be straightened by the pipe straightening machine, and its die shall be consistent with the outer diameter of steel pipe.

4.6 when the carbon steel pipe is hot adjusted, the bending part of the steel pipe shall be heated to 800-1000 ℃, and then it shall be placed on the platform and rolled repeatedly to make it straight. The flame straightening method can also be used.

The prefabrication size of steel pipe shall be processed according to figure 7. The following requirements shall be met during cutting:

4.7.1 stainless steel pipe shall be cut by mechanical or plasma method

4.7.2 the carbon steel pipe can be cut by flame, and the surface layer affecting the welding quality must be removed.

4.8 the welding groove processing of steel pipe shall meet the following requirements:

4.8.1 carbon steel pipe should be machined by mechanical method or flame processing

4.8.2 stainless steel pipe shall be machined by mechanical method. If special grinding wheel or stainless steel grinding wheel must be used for tube cutting.

4.8.3 if the steel pipe is processed by flame or plasma, the surface layer affecting the welding quality must be removed.

4.9 when the wall thickness difference on both sides of the welding groove is greater than the following values, it shall be thinned as required.

4.9.1 the inner wall difference of Sha pipeline is 0.5mm or the outer wall difference is 2mm;

4.9.2. The inner wall difference of SHB and SHC pipelines is 1 mm or the outer wall difference is 2 mm;

4.9.3. The outer wall difference of other pipes is 3mm.

4.10 the quality of groove shall meet the following requirements:

4.10.1 the surface shall be smooth without cracks, double skin, burr, convex and concave necks;

4.10.2 the slag, iron oxide and iron chips on the cutting surface shall be removed;

4.10.3 the inclination deviation of end face shall be 1% of the outer diameter of the pipe, but shall not exceed 2mm;

4.10.4 the groove size and angle shall meet the requirements.

管道预制加工按现场审查确认的管段预制图进行

（一） 4、管道预制加工