Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
Compared with JB 4728 - 2000, this standard has the following main changes:
——Design pressure in application scope has been improved to less than 100MPa from not greater than 35MPa;
——Steel grade in this standard adopts unified numerical code; steel grade comparison between the new and old standards in Appendix B (Informative) was added;
——Two austenitic stainless steel grades (S31703 and S39042) were added; four austenitic heat-resisting steel grades (S30409, S34779, S31609 and S31008) were added; two austenitic - ferritic stainless steel grades (S22253 and S220553) were added;
——Sulfur contents in a majority of steel grades were reduced;
——Nominal thickness range of all the steel forgings was enlarged;
——Tensile strength index of steel forging with nominal thickness greater than 100mm was improved;
——It is specified that Class I forgings are only applicable to S11306 and S30408 steel grades with nominal thickness less than or equal to 150mm.
Appendix A of this standard is normative, and Appendix B is informative.
This standard was proposed by and under the jurisdiction of the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).
Drafting organizations of this standard: Hefei General Machinery Research Institute, China National General Machinery Engineering Corporation, China Special Equipment Inspection and Research Institute, Anhui Bureau of Quality and Technical Supervision, Wuxi Falan Forging Co., Ltd., Shanghai Power Equipment Research Institute, Nanjing Develop Industry Co., Ltd., Changzhou Sunshine General Petrochemical Fittings Co., Ltd.
Drafting staffs of this standard: Zhang Xiaohu, Qin Xiaozhong, Zhang Yong, Yang Guoyi, Ai Zhibin, Zhang Rui, Teng Deming, Chen Zhiwei, Yin Lijun, Zhang Li.
National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262) is in the charge of the explanation of this standard.
The previous editions of the standards replaced by this standard are:
——JB 4728-1994;
——JB 4728-2000.
NOTE: The English version hereof has been translated by codeofchina.com directly from the openly-published Chinese standard NB/T 47010-2010(JB/T 4278). In the event of any discrepancy in the process of implementation, the Chinese version shall prevail.
Stainless and Heat-Resisting Steel Forgings for Pressure Equipments
1 Scope
This standard specifies the technical requirements, test methods and inspection rules of stainless and heat-resisting steel forgings for the pressure equipments.
This standard is applicable to the stainless and heat-resisting steel forgings for pressure equipments whose design pressure is less than 100 MPa.
2 Normative References
The following documents are indispensable for the application of this standard. For dated references, only the dated edition is applicable to this document. For undated references, the latest editions of the normative documents (including all the amendments) are applicable to this document.
GB/T 222-2006 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223 Methods for Chemical Analysis of Iron, Steel and Alloy
GB/T 228 Metallic Materials - Tensile Testing at Ambient Temperature (ISO 6892:1998(E))
GB/T 231.1 Metallic Materials-Brinell Hardness Test-Part 1: Test Method (ISO 6506.1:2005)
GB/T 6394 Metal-methods for Estimating the Average Grain Size (ASTM E112:1996)
GB/T 10561 Steel Determination of Content of Nonmetallic Inclusions-Micrographic Method Using Standards Diagrams (ISO 4967:1998)
GB/T 11170 Stainless Steel - Determination of Multi-Element Contents - Spark Discharge Atomic Emission Spectrometric Method (Routine Method)
GB/T 20066 Steel and Iron-Sampling and Preparation of Samples for the Determination of Chemical Composition (ISO 14284:1996)
JB/T 4730.3 Nondestructive Testing of Pressure Equipments-Part 3: Ultrasonic Testing
3 Terms and Definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
Hollow forging
It refers to the axisymmetrical hollow forging, whose axial length L is greater than its outer diameter D, as shown in Fig. 1a). t shall be the nominal thickness.
3.2
Ring forging
It refers to the axisymmetrical hollow forging whose axial length L is less than or equal to its outer diameter D, as shown in Fig. 1b). The smaller one of L and t shall be the nominal thickness.
3.3
Disk forging
It refers to the axisymmetrical solid forging, whose axial length L is less than or equal to its outer diameter D, as shown in Fig. 1c). L shall be the nominal thickness.
3.4
Bowl forging
It refers to the axisymmetrical forging with concave section, whose height H is less than or equal to its outer diameter D, as shown in Fig. 1d). The greater one of t1 and t2 shall be the nominal thickness.
3.5
Neck flange forging
It refers to the axisymmetrical hollow forging with two axial outside diameters, as shown in Fig. 1e). The greater one of t1 and t2 shall be the nominal thickness.
3.6
Bar forging
It refers to the solid forging with circular section, whose axial length L is greater than its outer diameter D, as shown in Fig. 1f). D shall be the nominal thickness.
It refers to the forging with rectangular section, whose length L is greater than its both side length a and b, as shown in Fig. 1g). The smaller one of a and b shall be the nominal thickness.
Figure 1
4 Order Contents
4.1 The Buyer shall indicate the standard number, steel grade, forging class, supply status and quantity, etc. in the order contract.
4.2 The Buyer shall provide order drawing.
4.3 When the additional requirements in Appendix A (Normative) of this standard and other requirements which exceed or are higher than this standard are used, they shall be indicated in the order contract by the Buyer.
5 Technical Requirements
5.1 Smelting process
The steel for forging shall be smelted through electric furnace or oxygen converter and also shall adopt external refining process.
5.2 Chemical Compositions
5.2.1 Chemical compositions (heat analysis) of the steel for forging shall be in accordance with those specified in Table 1.
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 Order Contents
5 Technical Requirements
6 Test Methods
7 Inspection Rules
8 Marking and Quality Certificate
Appendix A (Normative) Additional Requirements
Appendix B (Informative) Steel Grade Comparison Between the New and Old Standards
