X52 seamless pipeline production process

Keywords:seamless pipeline
First, the technical requirements
1, Specifications: 323.9mm × 11.125mm × 10000-12000mm seamless pipeline
2, The applicable standards and levels: API Spec 5L PLS1
3, Steel: X52, the melting analysis and product analysis in line with API Spec 5L. 
4, The continuous casting slab steel rolling, slab quality should be consistent with YB / T4149-2006 standard requirements. 
5, Steel tensile properties should be consistent with API Spec 5L. 

6, Pipe size deviation should be consistent with the provisions of the following table.

Sizes Process Outside diameter tolerance
Wall thickness deviation
Pipe end
323.9x11.125
Hot rolling control
-1.3mm~+1.3mm
-2.0mm~+2.0mm
10.5mm~12.5mm
Finished product inspection
-1.6mm~+1.6mm
-2.4mm~+2.4mm
10.3mm~12.79mm

7, Bending: 4mm / M; full length: ≤ 2 ‰.

8, Pipe end processing: pipe end beveling should not exceed 1.6mm. 
9, The surface quality of steel pipe: There should be no cracks, cracks, folding, rolling off, delamination, scarring and other defects in the seamless pipeline. These defects should be completely removed, and the outer diameter should not exceed the negative deviation after cleaning. The remaining wall thickness should be not less than negative deviation. 
10, Non-destructive testing: steel by magnetic flux leakage testing, testing level L4.
11, Water pressure: steel pipe pressure by branch, the minimum test pressure of 22MPa; test pressure dwell time not less than 5s.
 
Second, rolling process control
1, Production precautions
A. The chemical composition of billet, size specifications, the surface quality of the qualified test, in kind after checking before feeding furnace. 
B. Billet in the ring furnace heating system according to the provisions of this unit to ensure that the billet in the ring furnace heating evenly, not yin and yang, heating impervious, overheating or over-burning phenomenon, in case of rolling mill failure, as the case may be take cooling measures, and does not allow the billets in the high temperature area for a long time to stay in order to ensure the quality of steel (tube) billet heating.
3. The units, the process in strict accordance with the furnace to send steel logistics tracking system, fill the balance transfer card; mixed furnace may not be mixed phenomenon.

2, Rolling operation points
Process
Under the production plan → continuous casting slab inspection → cut → heating → perforation → rolling pipe → sizing → intermediate geometry inspection → cooling → straightening → length measurement → blowing soot → magnetic flux leakage testing → manual inspection → water pressure → spraying Standard → storage

Rolling requirements
Rolling should be punching machine, pipe rolling mill, sizing machine, straightening machine tool to check and confirm, of which focus on the piercing machine and rolling mill rolls, guide, head, sizing roller, straightening roller and other tools and the mandrel size, surface quality and lubrication quality, if cracks, sticking steel, defects, deformation and other defects or uneven surface of the mandrel lubrication should be promptly processed until all normal before production. Production process must be checked at any time the quality of deformation tools, control of the mill cooling water, enhance tool lubrication, to ensure that no scratches the surface of steel, cracks, cracks, rolling off, scarring and other defects.

3, Production process control
1) Ring furnace heating control: Fabric angle: 2.8º. Temperature control: preheating section 650 ~ 750 ℃, preheating a period of 950 ~ 1080 ℃, heating a period of 1100 ~ 1200 ℃, heating the second paragraph 1200 ~ 1250 ℃, heating three paragraphs 1260 ~ 1280 ℃, soaking a 1270 ℃ ~ 1310 ℃, both are 1270 ℃ ~ 1310 ℃ (normal production by the upper limit control). Heating time: 220 ~ 240 minutes.
2) Perforation machine control: When adjusting the hole type, the top reduction ratio should be less than or equal to 5%; the rolling speed should be less than 0.7M / S; and the capillary temperature should be controlled between 1200 ℃ and 1220 ℃. 
3) Rolling mill control: Rolling speed ≤ 0.35M / S; background open high-pressure water, waste pipe to be sprayed to the head and tail, but not black; shortage of tube temperature control in 1000 ℃ ~ 1100 ℃.
4) Small cooling bed: Open high-pressure water jacket and fan in this strong cold steel pipe. 
5) Sizing machine control: The use of thick-walled tube rolling speed; diameter inlet temperature ≤ 850 ℃; outlet temperature ≤ 750 ℃; background open high-pressure water for cooling. 
6) Hot sampling control: Open a first sampling, head and tail-like one, the wall thickness, diameter and length of the pipe carefully measured, and according to the measurement results indicate that the pipe mill and sizing machine to be adjusted accordingly, to be all geometric dimensions of the pipe meet the requirements of the process in order to produce continuously. Each batch must be sampled for inspection in the class.
7) Cooling bed control: Partition cloth; choose fast forward mode. In this group of batch, group batch method according to cut the number of packaging does not exceed 200 / batch.
8) Straightening machine control: Carefully adjust the straightening machine to ensure that the curvature of qualified, be careful not to make the steel tube correction and scars defects.
9) Pipe saw control: According to ensure the wall thickness, outer diameter precision and curvature of the head tail length, length length 10000mm-12000mm; pipe saw can not be cut into the pipe cutting machine length, be careful not to cause short ruler. 
10) Non-destructive flaw detection: One by one magnetic flux leakage testing, testing level L4; manual blind spot pipe end of the probe, testing level L4. Remaining magnetic test (≤ 30Gs), 1/50. 
11) Test bench control: Artificially by branch on the geometric dimensions of steel pipe, the curvature of the test, the quality of the steel pipe to check the internal and external, to exceed the allowable defects for grinding grinding clean, and re-geometry size re-examination. Inspection qualified steel pipe is allowed to be released to the next process, unqualified steel pipe to make identification and records, stored in the designated location. 
12) Water pressure: Pressure by the branch. 
13) Marking: Steel grade + standard + size (OD, wall thickness) + furnace batch number. Length and tube number indicate on the inner surface of the pipe. 

14) Mark: Hanging in each bundle of two signs (one at each end), the sign should be marked with steel grade, furnace number, size, weight, part number, count, inspection number. Each bundle must be the same batch number.

seamless pipeline

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