GB/T 14383-2021Forged fittings - Socket welding and threaded (English PDF)

1 Scope

China's national standard for forged socket welding and threaded pipe fittings - the elbows, tees, couplings, caps, unions and crosses used on small bore high pressure pipework in power stations, refineries, chemical plant and process systems generally. Small bore lines carry a disproportionate share of the failures in a piping system: they are numerous, they are often supported badly, they are subjected to vibration and to being stood on, and the fitting is where the wall is thickest and the stress concentration is highest. It specifies the dimensions, the materials, the technical requirements, the test methods, the inspection rules, and the marking, packaging, transport and storage of forged socket welding and threaded fittings. Being forged rather than cast is the point: the material has a worked structure with no porosity and no cast defects, which is what allows the fitting to be rated at the pressure of the pipe it joins. The requirements cover the pressure classes and the corresponding wall thicknesses, the materials and their composition and mechanical properties, the dimensions of the socket and of the thread and their tolerances - which are the whole of the interchangeability of the product - the surface condition and the permitted defects, the heat treatment, and the non-destructive examination where the class requires it. The socket geometry deserves particular attention: the gap that must be left between the pipe end and the bottom of the socket exists so that the weld is not restrained as it cools, and a fitting whose socket depth is out of tolerance produces a joint that cracks. Issued on 9 March 2021 and in force since 1 October 2021, it replaces GB/T 14383-2008. Amendment 1, GB/T 14383-2021/XG1-2025, was issued on 30 June 2025 and forms part of the same document.

This standard specifies the varieties and codes of forged socket welding and threaded pipe fittings, pressure grades, special connection forms, pipe sizes, and within the order Capacity, shape, dimensions and tolerances, materials, manufacturing, heat treatment, inspection and testing, marking, surface protection and packaging, and product quality certificates Requirements. This standard applies to piping systems whose nominal size is less than or equal to DN 100, the pressure class (Class) is 2 000, 3 000, 6 000 and 000 steel material forged socket welding and threaded pipe fittings.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document. GB/T The allowable deviation of the chemical composition of the finished product of 222 steel

GB/T 223 (all parts) Steel and alloy chemical analysis methods

GB/T 226 Steel Macrostructure and Defect Inspection Method

GB/T 228.1 Tensile test of metallic materials Part

3 Variety and code

The varieties and codes of pipe fittings are shown in Table 1.

4 Pressure rating

The pressure class (Class) of socket welded pipe fittings is 3 000, 6 000 or 9 000, the pressure rating of threaded pipe fittings is 2 000, 3 000 or 000.The pressure rating of this standard is only related to the corresponding steel pipe wall thickness (see Appendix A), and the corresponding relationship between the two is shown in Table 2.

2 The relationship between the pressure rating of the pipe fittings and the corresponding steel pipe wall thickness

5 Special connection form

5.1 The pipe fittings can be made into the end connection form of socket welding and thread combination. For the end connection form of this combination, it should be compared according to Table 2. The end of the low pressure grade determines the pressure grade of the pipe fitting.

5.2 With the agreement of the supplier and the demander, pipe fittings with other thread forms or other connection forms can be made; in addition, the pipe fittings should comply with other terms Provisions.

6 Take over size

6.1 See Appendix A for the dimensions of steel pipes connected with pipe fittings. The outer diameter of the steel pipe is divided into two series, I and II, and the outer diameter of I series is recommended. Elected When using the II series outer diameter, you should add II in the order content, and the manufacturer should determine the socket hole and the flow hole according to the II series outer diameter; in addition, The remaining dimensions of the pipe fittings should meet the requirements of this standard.

6.2 The outer diameter of II series is not suitable for threaded pipe fittings.

7 Order content

The purchaser shall provide all the information required for the purchase of goods in the order. This information shall include but not limited to the following.

---Variety or code (including special connection form requirements);

---Material grade;

---Pressure Level;

---Nominal size (the outer diameter of series I does not need to be added, and the outer diameter of series II should be marked with II) or thread size code; thread sub-sections should also be marked with length Degree type code;

---No. of this standard;

---Number of pieces;

---Additional requirements (see Appendix B) or supplementary regulations required.

Appendix A

(Normative appendix) Size of steel pipe connected with pipe fittings 25

Appendix B

(Normative appendix) Additional requirements 27

Appendix C

(Informative appendix) Commonly used raw materials for pipe fittings 30

Appendix D

(Informative appendix) Inspection and test summary table

This standard is in accordance with GB/T Drafting of the rules given in 1.1-2009. This standard replaces GB/T 14383-2008 "Forged Socket Welding and Threaded Pipe Fittings", with GB/T Compared with 14383-2008, except for editability In addition to the modification, the main technical changes are as follows:

---The variety of pipe fittings has been added (see Table 1);

---Added the eccentricity requirements for eccentric reducing pipe fittings (see 8.4.3);

---Modified the practice of using raw material grades as the material grades of pipe fittings, and established pipe fittings that are compatible with the material system of butt-welded pipe fittings Material grade (see 9.1,

9.2 in.2008 edition);

---Modified the content of heat treatment (see Chapter 11, Chapter 11 of the.2008 edition);

---Modified part of the content and parameters of inspection and test (see Chapter 12, Chapter 12 and Chapter 13 of the.2008 edition);

---Deleted the provisions of the verification test (see

13.2 of the.2008 edition);

---Modified the content of the logo (see Chapter 13, Chapter 14 of the.2008 edition);

---Modified the content of the product quality certificate (see Chapter 15, Chapter 16 of the.2008 edition);

---Modified the outer diameter of some steel pipes (see Appendix A, Appendix B of the.2008 edition);

--- Deleted this standard and ASME B16.11..2005 chapter number comparison table (see Appendix A of the.2008 edition);