Introduction of spiral steel tube carbon structural steel plate and standard

Introduction of spiral steel tube carbon structural steel plate and standard

Spiral steel pipe standard

1 Scope

This standard specifies the size, shape, weight, technical requirements, test methods, inspection rules, coatings, marking and certification of spiral submerged arc welded pipes (hereinafter referred to as "pipes") for low-pressure fluid conveying pipelines.

This standard applies to water, sewage, air, heating, steam and flammable liquids and other common low-pressure fluid pipes, steel pipes, and similar regulations, other steel pipes for fluid pipelines.

2 References

The provisions contained in the following standards, through the authority of this standard, constitute the provisions of this publication, the versions shown are valid, all standards will be revised, the parties using this standard should explore the latest version of the following standards.

GB / T 222-1984 Steel chemical sampling and chemical composition of finished product tolerances

GB / T steel and alloy chemical analysis method - Determination of acid soluble silicon content by reduced silicomolybdate photometric method

Sodium arsenite GB / T steel and alloy chemical analysis method - manganese content of sodium nitrite titration

GB / T steel and alloy chemical analysis method - phosphorus molybdenum blue method for the determination of phosphorus content

GB / T combustion tube furnace sulfur content potassium iodate titration steel and alloy chemical analysis method

Determination of carbon content after combustion - Volumetric tube method of gas GB / T steel and alloys

GB / T 241-1990 metal pipe hydraulic test method

GB / T 700-1988 carbon structural steel

GB / T 2651 to 1989 solder joint tensile test method

GB / T 3323-1987 Steel welded joints for radiography and quality grading

Photoelectric Emission Spectroscopy of GB/T 4336-1984 Carbon Steel and Low Alloy Steel

GB / T 6397-1986 Metal tensile specimens, SY / T oil and gas industry - L delivery of steel parts Technical conditions: A grade steel, SY / T oil and gas industry pressure pipe weld non-destructive testing method longitudinal Submerged arc welding and/or ultrasonic inspection lateral

Imperfect 3 symbols

The nominal diameter of the D-tube, mm;

T-tube nominal wall thickness, mm;

M - pipe line quality, kg / m;

P-hydrostatic pressure test, MPA;

S-pressure test hydrostatic pressure test, MPA;

H - welded reinforcement, mm.

4 size, shape and weight

Outer diameter and wall thickness

The nominal pipe diameter, nominal wall thickness should meet the requirements of Table 1.

Nominal pipe diameter tolerances shall be in accordance with Table 2 and measured with circumference.

Note: The nominal pipe diameter tolerance is converted to the periphery and can be rounded to the nearest millimeter.

The nominal pipe wall thickness tolerance shall comply with the requirements of Table 3. Micrometers can measure the accuracy of walls or other suitable non-destructive testing equipment. The measurement of the wall thickness micrometer shall be based on the nominal wall thickness measurement of the dispute or arbitration test.

Pipe length

General length: 6~12M. By agreement between the buyer and the manufacturer, the length of the pipe is usually extended or shortened.

Length length length length deviation + / - 500mm range is normal.

Precision Cut Length: An agreement between the buyer and the manufacturer that can provide a tighter length limit than the length of the cut of the fine steel pipe.

Roundness

The maximum diameter of the pipe within the pipe end shall not exceed 1% of the nominal diameter of 100mm, the minimum diameter shall be large, and shall not be used for measuring the maximum and minimum outer diameter calipers, the diameter of the lever exceeds 1%, or other regulatory measuring tools. to measure.

straight line

The bending of the steel pipe shall not exceed the length %. From the side of the surface pipe to the other end, pull a string or thin line parallel to the pipe axis, measure the string of tension, or use the side of the maximum distance of the thin wire tube.

Pipe end

If the spiral steel pipe is processed at the end of the groove. 30.. Cone angle, blunt edge size + / vertical axis is used as a reference to measure the ramp tube. The side edge burrs are not allowed to be delivered flat according to the buyer's requirements. After the agreement between you, you can also use other ramps.. + 0.50

The end of the steel pipe shall be perpendicular to the axis of the pipe. The limit deviation (beveled) shall be as follows: 813 mm The nominal deviation of the nominal outer diameter is less than or equal to the nominal diameter of the steel 813 mm, steel, limit deviation

Introduction of spiral steel pipe carbon structural steel plate

The high-quality carbon structural steel plate is a carbon steel containing less than 0.8% carbon. The steel contains less sulfur, phosphorus and non-metallic inclusions than the carbon structural steel, and has excellent mechanical properties. High-quality carbon structural steel can be divided into three categories according to different carbon content: low carbon steel (C ≤ 0.25%), medium carbon steel (C 0.25 ~ 0.6%) and high carbon steel (C > 0.6%). High-quality carbon structural steel is divided into normal manganese content (including manganese 0.25%~0.8%) and higher manganese content according to the manganese content.

High-quality spiral steel tubes are inseparable from high-quality steel sheets.

The introduction of high-quality steel plates begins with high-quality carbon structural steel plates.

High quality carbon structural steel sheets have a carbon content of less than zero.

8% carbon steel, which contains less sulfur, phosphorus and non-metallic inclusions than carbon structural steel, and has excellent mechanical properties.

High-quality carbon structural steel can be divided into three categories according to the carbon content: low carbon steel (C ≤ 0.

25%), medium carbon steel (C is 0.

25~0.

6%) and high carbon steel (C>0.

6%).

High-quality carbon structural steel is divided into normal manganese content (including manganese 0) according to the manganese content.

25%~0.

8%) and higher manganese content (containing manganese 0).

70%~1.

20%) two groups, the latter has good mechanical properties and processing properties.

Corrosion develops inward from the surface of the spiral steel pipe along the grain boundary, and there is no evidence of corrosion on the surface, but the grain boundary deposits loose corrosion products.

It can be seen from the metallographic microscope that the grain boundaries exhibit reticular corrosion.

Severe intergranular corrosion can cause the metal to lose strength and ductility and break under normal load.