GB/T 20409-2018Seamless multi-rifled steel tubes for high-pressure boiler (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 20409-2006 "internal thread seamless steel pipe for high pressure boiler", compared with GB/T 20409-2006, mainly The technical changes are as follows.

--- Added OM thread type (see 3.1);

--- Modified the illustration of the internally threaded tube, adding a side view of the internally threaded tube tooth type (see Chapter 3 of 3.2, 2006 edition);

--- Added the code and description of the internally threaded pipe (see 3.3);

--- Increased the size and thread parameters of the OM type internally threaded pipe (see 5.1);

--- Modified the internal thread tube size and thread parameter tolerance requirements (see 5.2, 2006 version 5.2);

--- Revised the length deviation requirement (see 5.3, 5.3 of the 2006 edition);

--- Increased out-of-roundness and uneven wall thickness requirements (see 5.5);

--- Removed the tag example (see 5.7 of the 2006 edition);

--- Increased steel grades 12Cr2MoG, 12Cr1MoVG, 10Cr9Mo1VNbN, 10Cr9MoW2VNbBN (see 6.1);

--- Revised chemical composition requirements (see 6.1, 2006 version 6.1);

--- Removed the manufacturing method of steel and tube blanks (see 6.2.1 of 2006 edition);

--- Increased pipe requirements and cold rolling processing methods (see 6.2);

--- Revised the requirements of the heat treatment system (see 6.3, 6.3 of the 2006 edition);

---Modified the mechanical properties requirements (see 6.4.1, 6.4.1 of the 2006 edition);

--- Increased hardness test requirements (see 6.4.3);

--- Revised the impact test requirements (see 6.4.4, 6.4.1 of the 2006 edition);

--- Revised the requirements for the flattening test (see 6.5.1, 6.5.1 of the 2006 edition);

--- Increased flaring test requirements (see 6.5.2);

---Modified hydraulic test requirements (see 6.6, 2006 version 6.5.2);

--- Revised the microstructure requirements (see 6.7, 2006 version 6.6.1);

--- Revised grain size requirements (see 6.8, 2006 version 6.6.2);

--- Revised the decarburization layer requirements (see 6.6.3, 2006 version 6.63);

--- Revised surface quality requirements (see 6.10, 2006 version 6.7);

--- Modified non-destructive testing requirements (see 6.11, 2006 version 6.8);

--- Revised test methods (see 7.1, 7.2 and 7.4, 2006 editions 7.1 and 7.3);

--- Revised inspection rules (see 8.2 and 8.4, 2006 editions 8.2 and 8.4).

1 Scope

This standard specifies the classification and code, order content, size, shape and weight, technical requirements, internal thread seamless steel pipe for high pressure boilers, Test methods, inspection rules, packaging, marking and quality certificates.

This standard is applicable to the production of cold drawn or cold rolled internal thread seamless steel tubes (hereinafter referred to as internal threaded tubes) for pressure vessels with high pressure and above.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 223.5 Determination of acid-dissolved silicon and total silicon content - Reducing silyl molybdate spectrophotometric method

GB/T 223.9 Determination of aluminium content of steels and alloys - chrome azure S spectrophotometric method

GB/T 223.11 Determination of chromium content in steels and alloys - either titration or potentiometric titration

GB/T 223.14 Methods for chemical analysis of steels and alloys - Determination of vanadium content by extraction spectrophotometric method

GB/T 223.19 Methods for chemical analysis of steels and alloys - s.

GB/T 223.23 Determination of nickel content in steels and alloys - succinimide spectrophotometric method

GB/T 223.26 Determination of molybdenum content of steels and alloys - thiocyanate spectrophotometric method

GB/T 223.30 Steel and alloy chemical analysis method - Determination of bromomandelic acid precipitation - arsenazo III spectrophotometric method Zirconium amount

GB/T 223.36 Methods for chemical analysis of steels and alloys - Distillation separation - Neutralometric titration

GB/T 223.40 Determination of bismuth content of steels and alloys

GB/T 223.43 Determination of tungsten content of steels and alloys - Gravimetric method and spectrophotometric method

GB/T 223.58 Determination of manganese content - Sodium arsenite - Sodium nitrite titration method

GB/T 223.59 Determination of phosphorus content in steels and alloys - phosphine molybdenum blue spectrophotometric method and bismuth phosphomolybdate blue spectrophotometric method

GB/T 223.68 Steel and alloy chemical analysis method - Determination of sulfur content by potassium iodate titration after combustion in tubular furnace

GB/T 223.69 Determination of carbon content of steels and alloys

GB/T 223.78 Determination of boron content by direct photometric method with curcumin

GB/T 223.84 Determination of titanium content in steels and alloys - Diantipymethylene methane spectrophotometric method

GB/T 223.85 Determination of sulfur content of steel and alloys - Infrared absorption method after induction furnace combustion

GB/T 223.86 Determination of total carbon content of steels and alloys - Infrared absorption method after induction furnace combustion

Detachment layer depth determination method for GB/T 224 steel

GB/T 228.1 tensile testing of metallic materials - Part 1

GB/T 229 metal material Charpy pendulum impact test method

GB/T 231.1 Brinell hardness test for metallic materials - Part 1. Test methods

GB/T 241 metal pipe hydraulic test method

GB/T 242 metal pipe flaring test method

GB/T 246 metal material tube flattening test method

GB/T 2102 steel pipe acceptance, packaging, marking and quality certificate

GB/T 2975 steel and steel products mechanical properties test sampling position and sample preparation

GB/T 4336 Determination of multi-element content of carbon steel and medium-low alloy steels by spark discharge atomic emission spectrometry (conventional method)

GB/T 4340.1 Vickers hardness test for metallic materials - Part 1. Test methods

GB/T 5310 seamless steel pipe for high pressure boiler

GB/T 5777-2008 Seamless steel tube ultrasonic flaw detection method

GB/T 6394 method for determination of average grain size of metals

GB/T 7735-2016 Automatic eddy current testing for seamless and welded (except submerged arc welding) steel pipe defects

GB/T 13298 metal microstructure inspection method

GB/T 20066 Sampling and sample preparation method for samples for determination of chemical composition of steel and iron

GB/T 20123 Determination of total carbon and sulfur content of steels - Infrared absorption method after high-frequency induction furnace combustion (conventional method)

GB/T 20124 Determination of nitrogen content of steels - Insulating gas fusion heat conduction method (conventional method)

GB/T 31925-2015 Ultrasonic inspection method for thick-walled seamless steel tubes

YB/T 5137 high pressure hot rolled and forged seamless steel tube round billet

3 Classification and code

3.1 The internal threaded pipe of this standard is divided into the following three categories according to the tooth type.

a) Type A. the helix angle is 30°, the thread side angle is 55°, and the thread top width (axial direction) is 8.28 mm;

b) Type B. the helix angle is 30°, the thread side angle is 50°, and the thread top width (axial direction) is 5.6mm or 6.64mm;

c) OM type. the helix angle is 40°, the thread side angle is 55°, the thread top width (axial direction) is 5.4mm or 5.6mm, the thread side The height of the straight section is not less than 60% of the height of the thread.

3.2 The internal threaded tooth profile is shown in Figure 1, and the toothed side is shown in Figure 2. Description.

I --- thread top width (circumferential); T --- thread top width (axial); N---thread lead; U --- thread top groove width (axial);

M---thread pitch (thread pitch equals thread lead divided by number of threads); Q --- helix angle; S --- nominal wall thickness; E --- minimum inner diameter; K---thread side angle; C --- thread root diameter; J --- thread height; D --- outer diameter. O --- thread root radius;

O --- thread root radius; v --- the height of the arc transition between the side of the thread and the top of the thread; h --- the height of the straight side of the thread side; w---the height of the arc transition between the side of the thread and the bottom of the thread; J --- thread height.

3.3 The following codes apply to this standard.

D outer diameter (if not specified, including nominal outer diameter and/or calculated outer diameter)

Smin minimum wall thickness

Sc average wall thickness (wall thickness calculated by dividing the difference between the outer diameter and the inner diameter of the root of the thread)

G thread number

4 Ordering content

Contracts or orders for ordering internally threaded pipes in accordance with this standard shall include, but are not limited to, the following.

a) standard number;

b) product name;

c) the grade of the steel;

d) size specifications;

e) thread tooth type;

f) the quantity ordered (weight or length);

g) Special requirements.

5 Size, shape and weight

6 Technical requirements

7 Test methods

7.1 The chemical composition analysis of the internally threaded pipe shall be carried out according to the rules of GB/T 20066, and the chemical composition analysis shall be generally in accordance with GB/T 4336. GB/T 20123, GB/T 20124 or other common methods, arbitration should be in accordance with GB/T 223.5, GB/T 223.9, GB/T 223.11 GB/T 223.14, GB/T 223.19, GB/T 223.23, GB/T 223.26, GB/T 223.30, GB/T 223.36, GB/T 223.40, GB/T 223.43, GB/T 223.58, GB/T 223.59, GB/T 223.68, GB/T 223.69, GB/T 223.78, GB/T 223.84, The provisions of GB/T 223.85 and GB/T 223.86 are carried out.

7.2 The thread parameters of the internally threaded pipe shall be not less than the interception length of the same specification, the same production process and no more than 200 The sample tube with two thread pitches is measured by a gage that meets the accuracy requirements after cutting. Other dimensions of the internally threaded pipe shall be in accordance with the accuracy The gauges are measured one by one.

7.3 The inner and outer surface quality of the internally threaded pipe shall be visually inspected under full lighting conditions.

7.4 Sampling methods and test methods for other inspection items of internally threaded pipes are to comply with the requirements of Table 11.

8 Inspection rules

9 Packaging, marking and quality certificate

The packaging, marking and quality certificate of the internally threaded pipe shall comply with the provisions of GB/T 2102.

Appendix A (informative) Theoretical weight of internally threaded pipe

The theoretical weight of the internally threaded pipe is given in Table A.1. The theoretical weight per metre of the internally threaded pipe (the density of the steel is 7.85kg/dm³) according to the formula (A.1) Calculation. In the formula.

Z --- theoretical weight per meter of internal threaded pipe, in kilograms per meter (kg/m); D---outer diameter, in millimeters (mm);

S --- nominal wall thickness (average wall thickness) in millimeters (mm); G---number of threaded heads; I --- Thread top width (circumferential) in millimeters (mm); Q---spiral angle, in degrees (°); J --- thread height in millimeters (mm);

K---The angle of the side of the thread, in degrees (°).