First, technical requirements
1, specification: 323.9mm * 11.125mm * 10000-12000mm seamless pipeline
2, applicable standards and levels: API Spec 5L PLS1.
3, steel number: X52, smelting analysis and product analysis conform to API Spec 5L.
4, the slab quality should meet the requirements of YB / T4149-2006 standard for continuous casting slab.
5, the tensile properties of steel should be in accordance with API Spec 5L.
6, the deviation of the pipe size should be in accordance with the provisions of the table below.
Dimensional process external diameter tolerance
Wall thickness deviation
Hot rolling control
-1.3mm ~ +1.3 millimeter
-2.0mm ~ +2.0 millimeter
10.5 millimeter to 12.5 millimeter
Finished product inspection
-1.6mm ~ +1.6 millimeter
-2.4mm ~ +2.4 millimeter
10.3 millimeter to 12.79 millimeter
7, the degree of bending: 4mm / M; full length: less than 2 per thousand.
8, pipe end processing: tube end skew should not exceed 1.6mm.
9, the surface quality of steel pipe: seamless pipes should have no defects such as cracks, cracks, folding, falling off, delamination, scars and so on. These defects should be completely eliminated and the external diameter should not exceed the negative deviation after cleaning. The residual wall thickness should not be less than the negative deviation.
10, nondestructive testing: the steel is detected by magnetic flux leakage and the detection level is L4.
11, water pressure: branch pipe pressure, minimum test pressure 22MPa; test pressure residence time not less than 5S.
Two is the control of the rolling process
1, matters of attention to production
A. steel billet chemical composition, size, surface quality inspection, check before the material inspection.
In the annular heating system, the B. billet ensures that the billet in the annular furnace is heated evenly, not Yin and Yang, heating water, overheating or overheating. In case the rolling mill fails, the cooling measures are taken, and the billet is not allowed to stay in the high temperature region for a long time to ensure the heating quality of the billet (tube). .
3. units, strictly follow the furnace to send steel logistics tracking system, fill in the balance transfer card, mixing furnace may not be mixed.
2, rolling work point
Production planning, continuous casting slab inspection, cutting, heating, perforation, pipe rolling, sizing, middle geometry inspection, cooling, straightening, length measurement, blowing ash, magnetic flux leakage testing, manual inspection, water pressure, spraying standard and storage
Rolling mill should be a punching machine, pipe mill, sizing machine, straightening machine and other tools to check and confirm, which focuses on the piercer and rolling mill roll, guide, head, diameter roller, straightening roll and other tools and axis size, surface quality and lubrication quality, if cracks, sticky steel, defects, deformation and other defects or tables Lubrication of mandrel with uneven surface should be handled in a timely manner until normal before production. In the process of production, the quality of the deformation tool must be checked at any time, the cooling water of the mill is controlled, the lubricity of the tool is enhanced, and the defects of the steel surface, such as scratch, crack, crack, roll and scar, are ensured.
3, production process control
1) ring furnace heating control: fabric angle: 2.8. Temperature control: preheating section 650 ~ 750 C, preheating section 950 to 1080 C, heating section 1100 to 1200, heating section 1200 to 1250 degrees, heating section 360 ~ 1280 degrees, immersion 1270 ~ 1310, are 1270 degrees to 1310 (through upper limit control of normal production). Heating time: 220 to 240 minutes.
2) perforator control: when adjusting the pass, the maximum deceleration ratio should be less than or equal to 5%; the rolling speed should be less than 0.7M / S; the capillary temperature should be controlled between 1200 and 1220.
3) rolling mill control: the rolling speed is less than 0.35M/ S; in the background of high pressure water, the waste pipe should be sprayed to the head and tail, but not black; the temperature control of 1000 ~ 1100 C is not enough.
4) small cooling bed: open high pressure water jacket and fan in strong cold steel pipe.
5) sizing machine control: using thick wall tube rolling speed; inlet diameter less than 850 degrees C; outlet temperature less than 750 degrees C; background open high pressure water cooling.
6) heat sampling control: opening the first sampling head, taudy sample, carefully measuring the tube wall thickness, pipe diameter and length, and according to the measurement results, the tube mill and sizing machine should be adjusted accordingly. All the geometric sizes of the pipes are in accordance with the process requirements for continuous production. Each batch must be sampled.
7) control of cold bed