This standard is developed according to the rules given in GB/T 1.1-2009 Directives for Standardization - Part 1: Structure and Drafting of Standards.
This standard replaces NB/T 47009-2010 Alloy Steel Forgings for Low Temperature Pressure Equipment and has the following main technical changes with respect to NB/T 47009-2010:
——The contents on design pressure and temperature are cancelled from Scope;
——06Ni9D alloy steel forging used at -196℃ is added;
——Relevant requirements of order contents are refined;
——Requirements on macroscopic inspection are added;
——KV2 in -100℃ impact test for 08Ni3D forging is revised as 60J;
——The quality grade for steel forging ultrasonic testing is increased;
——The criteria permissible for welding repair are modified;
Annex A in this standard is normative.
This standard was proposed by and is under the jurisdiction of the China Standardization Committee on Boilers and Pressure Vessels (SAC/TC 262).
The previous editions of the standard replaced by this standard are as follows:
——JB 4727-1994;
——JB 4727-2000;
——NB/T 47009-2010.
Alloy Steel Forgings for Low Temperature Pressure Equipment
1 Scope
This standard specifies terms and definitions, order contents, technical requirements, test methods, inspection rules as well as marking and quality certificate of alloy steel forgings for low temperature pressure equipment.
2 Normative References
The following documents for the application of this document are essential. For dated reference, only the edition cited applies. For undated reference, its latest edition (including any amendments) applies.
GB/T 222 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223 Methods for Chemical Analysis of Iron, Steel and Alloy (Applicable Parts)
GB/T 226 Test Method for Macrostructure and Defect of Steel by Etching
GB/T 228.1 Metallic Materials - Tensile Testing - Part 1: Method of Test at Room Temperature
GB/T 229 Metallic Materials - Charpy Pendulum Impact Test Method
GB/T 4336 Carbon and Low-alloy Steel - Determination of Multi-element Contents - Spark Discharge Atomic Emission Spectrometric Method (Routine Method)
GB/T 6394 Metal-methods for Estimating the Average Grain Size
GB/T 10561 Steel-Determination of Content of Nonmetallic Inclusions-Micrographic Method Using Standards Diagrams
GB/T 13298 Inspection Methods of Microstructure for Metals
GB/T 20066 Steel and Iron - Sampling and Preparation of Samples for the Determination of Chemical Composition
GB/T 20123 Steel and Iron - Determination of Total Carbon and Sulfur Content Infrared Absorption Method after Combustion in an Induction Furnace (Routine Method)
GB/T 20124 Steel and Iron - Determination of Nitrogen Content - Thermal Conductimetric Method after Fusion in a Current of Inert Gas (Routine Method)
NB/T 47013.3 Nondestructive Testing of Pressure Equipments - Part 3: Ultrasonic Testing
NB/T 47013.4 Nondestructive testing of pressure Equipments - Part 4: Magnetic Particle Testing
NB/T 47013.5 Nondestructive Testing of Pressure Equipments - Part 5: Penetrant Testing
3 Terms and Definitions
3.1
hollow forging
the axisymmetric hollow forging with axial length L greater than outside diameter D, as shown in Figure 1a); t refers to nominal thickness
3.2
ring forging
the axisymmetric hollow forging with axial length L less than or equal to outside diameter D, as shown in Figure 1b); L or t, whichever is smaller, refers to nominal thickness
3.3
disk forging
the axisymmetric solid forging with axial length L less than or equal to outside diameter D, as shown in Figure 1c); L refers to nominal thickness
3.4
bowl forging
the axisymmetric forging with axial length H less than or equal to outside diameter D and with concave section, as shown in Figure 1d); t1 or t2, whichever is larger, refers to nominal thickness
3.5
neck flange forging
the axisymmetric hollow forging with two outside diameters in axial direction, as shown in Figure 1e); t1 or t2, whichever is larger, refers to nominal thickness
3.6
bar forging
the solid forging with axial length L greater than outside diameter D and with circular section, as shown in Figure 1f); D refers to nominal thickness
the forging with length L greater than two side lengths a and b and with rectangular section, as shown in Figure 1g); a or b, whichever is smaller, refers to nominal thickness
a) Hollow forging b) Ring forging
c) Disk forging d) Bowl forging
e) Neck flange forging f) Bar forging (circular section)
g) Bar forging (rectangular section)
Figure 1 Forging Shape
4 Order Contents
The order contract by reference to this standard shall include the following contents:
a) Product name;
b) Order drawing;
c) Standard No.;
d) Material designation;
e) Forging grade;
f) Quantity (or quality);
g) Delivery state (including heat treatment and surface requirements);
h) Non-destructive testing requirements;
i) Additional technical requirements.
5 Technical Requirements
5.1 Smelting method
Steel for forgings shall be killed steel subject to electric furnace or oxygen converter smelting and external refining.
5.2 Chemical composition
5.2.1 Melting analysis
5.2.1.1 Designation and chemical composition of steel for forgings (melting analysis) shall meet the requirements of Table 1.
5.2.1.2 As required by the purchaser, the lower limit of nickel content in 16MnD and 20MnMoD steel may be specified.
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
Annex A (Normative) Additional Requirements
