NB/T 47010-2017Stainless and heat-resisting steel forgings for pressure equipment (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009 "Directives for standardization - Part 1: Structure and drafting of standards".

This standard replaces NB/T 47010-2010 "Stainless and heat-resisting steel forgings for pressure equipment"; incorporates the relevant content of JB/T 9626-1999 "Specification for boiler forging". Compared with NB/T 47010-2010, the main technical changes are as follows:

- CANCEL the content about design pressure in the Scope;

- DETAIL the relevant requirements for order content;

- ADD the macroscopic inspection requirements;

components, ADD the metallographic inspection requirements;

- ADD the quality level requirements for ultrasonic testing of steel forgings;

- MODIFY the allowable criteria for welding repair;

- ADD the steel forgings designations of 3 valves and special components, including S32590, S42020, S42030, etc.;

- ADD the high temperature mechanical properties table of commonly used forging steel.

Appendix A and Appendix C of this standard are informative appendixes. Appendix B is a normative appendix.

This standard was proposed by AND shall be under the jurisdiction of the National Boiler and Pressure Vessel Standardization Technical Committee (SAC/TC 262).

The main drafters of this standard: Zhang Xiaohu, Zhang Yong, Zhang Rui, Jiang Heng, Zhang Li, Zhang Xian, Zhang Wenhui, Yang Guoyi, Chen Zhiwei, Zhang Qingxiang, Zhang Weidong, Feng Yan, Yang Huachun, Wang Jinguang.

1 Scope

This standard specifies the terms and definitions, order content, technical requirements, test methods, inspection rules, markings and quality certificates, of stainless steel and heat-resisting steel forgings for pressure equipment.

2 Normative references

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable to this standard.

3 Terms and definitions 3.1

Axisymmetric hollow forgings, which have an axial length L greater than its outer diameter D, as shown in Figure 1a). t is the nominal thickness.

Axisymmetric hollow forgings, which have an axial length L less than or equal to its outer diameter D, as shown in Figure 1 b). The smaller of L and t is the nominal thickness.

Axisymmetric solid forgings, which have an axial length L less than or equal to its outer diameter D, as shown in Figure 1c). L is the nominal thickness.

Axisymmetric forgings, which have a concave cross-section AND an axial length H less than or equal to its outer diameter D, as shown in Figure 1 d). The larger of t1 and t2 is the nominal thickness.

Axisymmetric hollow forgings, which have two outer diameters in the axial direction, as shown in Figure 1 e). The larger of t1 and t2 is the nominal thickness.

A solid forging, which has a circular cross-section AND an axial length L greater than its outer diameter D, as shown in Figure 1 f). D is the nominal thickness.

Forgings, which have a rectangular cross-section AND a length L greater than the lengths a and b on both sides, as shown in Figure 1 g). The smaller of a and b is the nominal thickness.

4 Order content

The order contract, which adopts this standard, shall include the following contents:

g) Delivery status (including heat treatment and surface requirements);

5 Technical requirements

6 Test method

7 Inspection rules

8 Markings and quality certificates

8.1 The marking shall be printed on the obvious part of the forging OR the place designated by the purchaser. The position and method, of printing the mark, shall not affect the final use of the forging. For small forgings, a mark can be affixed on the packing box.

8.2 Forgings, which are inspected and delivered, according to this standard, shall have the following marks:

8.3 When the forgings are delivered, they shall be accompanied by a quality certificate, which includes:

Appendix A Forgings for boiler's matching valves AND special components

Appendix B Additional requirements

This requirement is implemented, only when the buyer stipulates in the order contract. It may use one or more of them. The details of the additional requirements shall be negotiated by the supplier and the buyer.

Before the mechanical property test, all specimen blanks shall be heat treated one or more times, below the critical temperature, which is mainly based on the expectation that, forging products will subject to post-weld heat treatment or other heat treatments, during the container manufacturing process. The buyer shall provide the supplier, with detailed heat treatment specifications, including temperature, holding time, cooling rate.

B.2 Use thermal buffer ring or ring segment for heat treatment

Before the heat treatment of the forging, weld the edge of a thermal buffer ring, which has a section of at least t x t (t is the nominal thickness of the forging) OR a ring segment, which has a section of at least t x t and an arc length of at least 3t, on the sampling end of the forging. The thermal buffer ring or ring segment is made of carbon steel or low alloy steel, which has good weldability. After the forging is heat treated, cut off the thermal buffer ring or ring segment. The specimen is taken from the area of the forging, that is thermally buffered by the thermal buffer ring or ring segment. When a thermal buffer ring segment is used, the specimen shall be taken, from the forging part corresponding to the middle 1/3 of the arc length, of the thermal buffer ring segment. The position of the specimen shall be at least 13 mm, away from the thermal buffer surface of the forging, AND at least t/4 from the heat-treated surface of the forging.

Appendix C High temperature mechanical properties