DL 5190.5-2019Technical specification for thermal power erection and construction. Part 5: Piping and system (English PDF)

2.0.1 Nominal size

Piping system components are identified by a combination of letters and numbers. It consists of letters DN and integer numbers. This number the characters are directly related to the characteristic dimensions such as the aperture or outer diameter (in mm) of the end connector.

2.0.2 Nominal pressure

It is related to the mechanical properties and dimensional characteristics of the piping system components, and is used as a reference letter and number combination identification. by the letters PN and numbers.

2.0.3 Pipe piping

It is composed of pipeline components and pipeline supports and hangers for conveying, distributing, mixing, separating, discharging, measuring or controlling Control fluid flow.

2.0.4 Piping components

Components used to connect or assemble into pipelines, including pipes, pipe fittings, flanges, gaskets, fasteners, valves, strainers and compensator, etc.

2.0.5 Pipe or tube

The cross-section used to transport fluid is a circular pipe component.

2.0.6 Pipe fittings

A category of piping components, including elbows or elbows, tees, sockets, reducers, and heads.

2.0.7 Pipe support and hanger

Various groups used to bear pipeline load, constrain pipeline displacement and control pipeline vibration, and transfer load to bearing structure the general term for parts or devices, but does not include civil structures.

2.0.8 Valves

The totality of mechanical products with movable mechanism used to control the medium in the pipeline.

2.0.9 Pipe compensators

It is connected with the pipeline to absorb and compensate the pipeline thermal expansion, cold contraction and other displacement devices.

2.10 Bent pipes bends

It has a larger bending radius and is used to change the direction of the pipe.

2.0.11 Elbows

It has a smaller bending radius and is used to change the direction of the pipe.

2.0.12 Welding elbows miter elbows

Elbows formed by pipe or steel plate welding, and pipe segment splicing with mitered welds that are not perpendicular to the longitudinal axis of the pipe Become.

2.0.13 Supervision section of pipe

The section of the steam pipeline used for metallographic structure and hardness tracking inspection.

2.0.14 Creeping inflation measuring point

Set on the supervision section, the device or mark for the creep deformation measurement of the pipeline.

2.0.15 Roundness

The ratio of the difference between the maximum outer diameter and the minimum outer diameter on the same circular section of the bent part of the elbow to the nominal outer diameter.

2.0.16 Wave degree wave rate

Ratio of wave height to outer diameter 2.0.17 the four piping Main steam pipeline, high temperature reheat steam pipeline, low temperature reheat steam pipeline, high pressure water supply pipeline.

DL/T 5190.5-2019

2.0.18 Valve pressure grade

4.1 General rules

4.1.1 The pipeline components and supports and hangers should have the manufacturer's product quality certification documents.

4.1.2 The inspection before use of the pipeline components and supports and hangers shall meet the following requirements.

1 Check the model, specification, material, quantity and logo according to the requirements of the design documents;

2 The geometric dimensions meet the requirements of the corresponding product standards, and the material identification is clear and complete;

3 No cracks, no shrinkage, no slag inclusion, no sticky sand, no folding, no missing welding, no heavy leather and other defects on the surface;

4 The depth of the depression should not exceed the negative deviation of the nominal wall thickness, and the actual wall thickness after treatment should not be less than the design minimum wall thickness.

4.1.3 The alloy steel pipe components and the alloy steel supports and hangers should be re-examined by spectrum and marked with material.

4.2 Pipe inspection

4.2.1 Before the construction of pipelines with a working pressure of not less than 5.9MPa or a working temperature of not less than 400°C, the manufacturer should compare the quality certification documents confirm that the following items meet the requirements.

1 Test results of mechanical properties such as tensile strength, yield strength and elongation;

2 Impact toughness test results;

3 Metallographic analysis results of alloy steel pipes.

4.2.2 The purchasing unit shall conduct quality inspection and acceptance according to the contract provisions during the claim period for imported pipes. In addition to the technical in addition to the technical conditions, there should be a customs declaration form and a commodity inspection certificate.

4.2.3 The inspection of the main steam pipe, reheat steam pipe and steam guide pipe shall meet the following requirements.

1 The factory mark such as steel stamp or paint mark on the surface of the steel pipe shall be consistent with the manufacturer's product mark;

2 The inner and outer surfaces of the steel pipe should not have defects such as cracks, folds, folds, scars, separation, etc.; cracks on the surface of the steel pipe, Remove mechanical scratches, and defects with a depth of more than 1.5mm. The actual wall thickness of the removed area should be greater than the design minimum wall thickness.

thick;

3 The inner surface of the hot-rolled (extruded) steel pipe should not have a straight line defect with a depth greater than 5% of the wall thickness and a maximum depth greater than 0.4mm.

trap;

4 The wall thickness of the steel pipe meets the design requirements;

5 30% of the alloy steel pipes of the same specification shall be sampled for hardness inspection, and at least one of each specification shall be spot-checked;

6 The metallographic inspection of alloy steel pipes shall be carried out according to 10% of the number of the same specifications, and at least one of each batch shall be randomly checked;

7 The steel pipe shall be subjected to ultrasonic non-destructive testing according to 20% of the same specifications;

8 For low-temperature reheat steam pipes with longitudinal welds, 20% of the number of pipes of the same specification shall be selected according to the appearance quality of the welds.

Test (at least one sample).

4.3 Pipe fitting inspection

4.3.1 The inspection of elbows and pipes shall meet the following requirements.

1 The surface has no defects such as cracks, no folds, no heavy leather, no dents and sharp scratches.

2 The geometric size check of elbows and elbows shall meet the following requirements.

1) The roundness of hot-bending pipes is less than 7%; the roundness of cold-bending pipes is less than 8%; the working pressure is greater than 8MPa, the roundness is less than 5%;

2) When the working pressure of the elbow is not less than 10MPa, the roundness is less than 3%; when the working pressure is less than 10MPa, the roundness Degree is less than 5%;

DL/T 5190.5-2019

3) Spectral inspection of alloy steel elbows and pipes one by one;

4) Hardness inspection of alloy steel elbows and pipes;

5) Perform metallographic inspection on alloy steel elbows and pipes according to 10% of the same specifications.

Not less than 1 piece;

6) The outer arc surface of elbows and elbows shall be subjected to non-destructive inspection and random inspection according to 10% of the sample quantity of the same specification.

4.3.2 The inspection of forged, hot-pressed and welded tees and reducers shall meet the following requirements.

1 The surface has no defects such as cracks, no folds, no heavy skins, no dents and sharp scratches;

2 Alloy steel tees and reducers shall be subjected to wall thickness measurement;

3 Spectral inspection of alloy steel tees and reducers one by one;

4 Alloy steel tees and reducers shall undergo hardness inspection;

5 Alloy steel tees and reducers shall undergo metallographic inspection at 10%, and there shall be no less than 1 piece of the same specification;

6 The surface non-destructive test and ultrasonic spot check of the three links and reducers shall be carried out at 10%, and there shall be no less than 1 piece of the same specification.

4.4 Inspection of flanges, gaskets and fasteners

4.4.1 The flange inspection shall meet the following requirements.

1 The sealing surface is smooth and smooth, without pores, cracks, burrs, and no through grooves;

2 Flanges with concave-convex surface or concave-convex ring fit well, and the height of the convex surface should be greater than the depth of the groove;

3 The supporting surface of the connecting bolt on the flange end face is parallel to the flange joint surface;

4 Check the dimensions of the flange and the flange to be connected on the equipment. The flange thickness tolerance meets the requirements of Table 4.4.1;

5 The gasket material of the flange meets the design requirements. When there is no design requirement, select it according to Appendix C.

4.4.2 Gasket inspection should meet the following requirements.

1 The surface of the metal gasket has no cracks, no burrs, no through scratches, no rust, etc., and its hardness is lower than that of the flange;

2 Metal gaskets and spiral wound gaskets should not have defects such as radial scratches and looseness;

3 When large-diameter gaskets need to be spliced, use oblique lap joints or labyrinth joints instead of flat joints;

4 The inner diameter of the gasket is 2mm~3mm larger than the inner diameter of the flange;

5 Spectral inspection for alloy steel gaskets;

6 The surface of non-metallic gaskets should be flat, without warping, deformation, slag inclusion, bubbles, impurities and other defects, and the edge cutting should be neat During storage, it should be placed in a dry and ventilated warehouse at room temperature to prevent direct exposure, squeeze, bend and close to heat.

source.

4.4.3 The fastener inspection shall meet the following requirements.

1 The thread surface is smooth and free of dents, cracks, rust, burrs and other defects;

2 The bolts and nuts fit well, without looseness and jamming;

3 For alloy steel fasteners, the product identification, quantity and quality inspection form should be checked according to the product standard, including chemical Chemical composition, low power and high power structure, mechanical properties;

4 Alloy steel, high-temperature alloy bolts and nuts should be subjected to spectral inspection, and spectral inspection spots should be polished and eliminated;

5 For bolts whose working temperature is above 400°C and whose specifications are not less than M32, the following inspections shall be carried out one by one.

1) Ultrasonic testing of bolts;

2) Spectral inspection of alloy steel bolts and nuts;

3) Inspection of the hardness of bolts and nuts;

DL/T 5190.5-2019

6 Bolts whose working temperature is above 400°C and whose specifications are greater than M32 should be spot-checked by metallographic structure.

The number of bolts for random inspection shall not be less than 1 piece;

7 Washer inspection shall meet the following requirements.

1) The surface is smooth and clean, without rust, dust, oil and water stains;

2) The washer has no burrs and mechanical defects;

3) The coating is firm, smooth and dense, without pinholes;

4) Spectral inspection of alloy steel washers;

5) For hardness testing, refer to Item 5.4.3 of this section.

4.5 Valve inspection

4.5.1 The valve inspection shall meet the following requirements.

1 The model, specification and material of the valve meet the design requirements;

2 The outer surface of the cast valve casing is smooth and clean, without cracks, shrinkage holes, burrs, sand inclusions and sharp scratches;

3 No cracks, no folds, no forgings, no spots, no heavy skins, no dents, sharp scratches and other defects on the forging surface;

4 The surface of the welding seam is smooth, without cracks, pores, undercuts, missing welds, no weld bumps and other defects;

5 The inside of the valve cavity is clean, the valve sealing surface and flange joint surface are intact, no burrs, no through grooves;

6 The valve handle or handwheel operation is flexible and light, without jamming. The disc or spool of the check valve is flexible and correct, no eccentricity, displacement or skew;

7 The threads of main parts such as stem, stem nut and connecting nut are smooth and clean, without burrs, dents and cracks Other defects

8 The operating mechanism and transmission device are checked and adjusted according to the design requirements, with flexible actions and correct instructions;

9 There is a medium flow arrow mark on the valve housing;

10 Spectral inspection of alloy steel valve housing piece by piece;

11 Valve housings of the same specification with operating temperature not less than 400°C are subjected to non-destructive testing at 20%, and at least 1 spot check for each specification Pieces;

12 Carry out hardness test on low alloy steel and 10%Cr steel valve housings according to 10% and 50% of the quantity.

4.5.2 The valve sealing test shall meet the following requirements.

1 Before installation, the shut-off valve and check valve should be sealed test;

2 The sealing test shall meet the technical requirements. When the manufacturer does not require it, the sealing test pressure should meet the following requirements.

1) PN series valve is 1.1 times the nominal pressure;

2) When the temperature of the medium exceeds 425°C, it is 1.25 times the working pressure;

3) PN series butterfly valves and check valves are 1.0 times the nominal pressure;

4) CLASS series butterfly valves and check valves are 1.0 times the maximum allowable working pressure at 30°C.

3 Perform the upper sealing test for valves with upper sealing performance. During the test, the upper sealing surface should be closed and the packing pressure should be loosened.

After passing the sealing test, press the packing gland, and then carry out the sealing test of the valve housing;

4 The valve sealing test medium is clean water, and the water temperature should be 5°C~50°C;

5 The method of sealing test shall meet the following requirements.

1) For valves with one-way sealing and marked with medium flow direction signs, pressurize the inlet side. Check valve, out Oral pressure;

2) Two-way sealing valve, pressurize each end of the closed valve successively to check the sealing of the sealing surface of the outlet end;

3) For multi-channel sealed valves, the test medium is introduced into the sealed channel for pressurization in turn;

4) The centerline lining symmetrical butterfly valve whose working pressure is less than 2.0 MPa can be tested in one direction;

Other connection forms of elastic sealing seat butterfly valves are subjected to two-way sealing test; valves with a flow direction mark are reversed During the test, the sealing test is carried out at the maximum allowable working pressure.

DL/T 5190.5-2019

6 The test time is not less than 5min, and the ambient temperature during the test is not less than 5°C. When it is lower than 5°C, anti-freezing measures shall be taken;

7 For valves with a nominal size not less than DN600, oil or water can be used for leakage inspection in the leak test;

8 The safety valve cold test report is provided by the manufacturer, and the safety valve should be tuned by a qualified verification unit before installation and provide reports;

9 Before the valve sealing test, the joint surface should be cleaned up, and the sealing packing between the valve cover and the valve stem should comply with Appendix D Requirements;

10 After the valve's sealing test is qualified, the stagnant water should be drained and clearly marked, and the ports should be temporarily sealed tightly and separated Class properly stored;

11 High-pressure valves and ultra-high-pressure valves should be 100% tested for tightness; medium and low-pressure valves should be tested from ...