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NB/T 47018-2017 consists of the following five sections under the general title Technical permission of welding materials for pressure equipment:
——Section 1: General rule;
——Section 2: Electrodes for steel;
——Section 3: Steel electrodes and rods for gas shielded arc welding;
——Section 4: Electrodes and fluxes for submerged arc welding;
——Section 5: Stainless steel strip electrodes and fluxes for overlay welding.
This is Section 3 of NB/T 47018-2017.
This section is developed in accordance with the rules given in GB/T 1.1-2009 Directives for standardization - Part 1: Structure and drafting of standards.
This section is a revision of NB/T 47018.3-2011 Technical permission of welding materials for pressure equipment - Section 3: Steel electrodes and rods for gas shielded arc welding. The following main technical changes have been made with respect to NB/T 47018.3-2011:
——GB/T 25774.1, GB/T 29713, YB/T 5092 and AWS A5.9 are added in the “Normative references”;
——Another 33 electrode codes are added, including 11 codes of carbon steel and low-alloy steel electrodes: ER50-3, ER50-G, ER60-G, ER49-A1, ER55-B6, ER55-D2-Ti, ER55-D2 ER55-G, ER62-D2, ER60-G and ER62-G; and 22 codes of stainless steel electrodes: S308, S308H, S308L, S308LSi, S309, S309L, S309LSi, S309Mo, S309LMo, S310, S316, S316H, S316L, S316LSi, S317 , S317L, S318, S321, S347, S410, S430 and S2209;
——The sulfur and phosphorus content values of some of the original low-alloy steel electrodes and rods are modified, and those of the newly added electrode models are specified;
——The impact test requirements for the deposited metal of original electrode and rod models are adjusted, and those for the newly added low-alloy steel electrodes and rods are supplemented;
——The tensile test requirements for deposited metal of electrodes and rods are added;
——Transverse bending specimen is allowed in bend test, and the requirement that retest is allowed after increasing bending center diameter is added;
——The determination methods (mercury method or thermal conductivity method) and acceptance criteria for the diffusible hydrogen content in deposited metal are re-specified;
——Annex A - “A comparison of stainless steel electrode models, and domestic and foreign designations and categories” and Annex B - “Tensile properties of the deposited metal of stainless steel electrodes and rods” are added.
This section was proposed by and is under the jurisdiction of the National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).
The previous edition of this section is as follows:
——NB/T 47018.3-2011.
Technical permission of welding materials for pressure equipment
Section 3: Steel electrodes and rods for gas shielded arc welding
1 Scope
This section of NB/T 47018-2017 specifies the technical requirements, mechanical property and bend tests of deposited metal, and product identification of steel electrodes and rods for gas shielded arc welding.
This section is applicable to carbon steel, low-alloy steel and stainless steel electrodes and rods for gas shielded arc welding of pressure equipment.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2653 Bend test methods on welded joints
GB/T 8110 Welding electrodes and rods for gas shielding arc welding of carbon and low alloy steel
GB/T 25774.1 Test methods for welding consumables - Part 1: Preparation and testing of deposited metal specimens for mechanical properties in steel, nickel and nickel alloys
GB/T 29713 Wire electrodes, strip electrodes, wires and rods for arc welding of stainless and heat resisting steels
NB/T 47013.2 Nondestructive testing of pressure equipment - Part 2: Radiographic testing
NB/T 47014 Welding procedure qualification for pressure equipment
NB/T 47018.1 Technical permission of welding materials for pressure equipment - Part 1: General rule
YB/T 5092 Stainless steel wires for welding
AWS A5.9/A5.9M:2006 Specification for bare stainless steel welding electrodes and rods
3 Technical requirements
3.1 General
a) In addition to the requirements of GB/T 8110, the carbon steel and low-alloy steel electrodes and rods for gas shielded arc welding of pressure equipment shall also meet the requirements of NB/T 47018.1 and this section;
b) In addition to the requirements of GB/T 29713, the stainless steel electrodes and rods for gas shielded arc welding of pressure equipment shall also meet the requirements of YB/T 5092, NB/T 47018.1 and this section;
c) See Annex A for the comparison of the stainless steel electrodes models in this section and the domestic and foreign designations and categories.
3.2 Roundness of electrodes
The out-of-roundness of the electrodes shall not be greater than 40% of the diameter tolerance, but 5% of the tested electrodes are allowed to have an out of roundness greater than 40% of the diameter tolerance but not greater than 50% of it.
3.3 Chemical composition of electrodes
See Table 1 for the requirements for sulfur and phosphorus contents in deposited metal of steel electrodes and rods for gas shielded arc welding of pressure equipment.
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Table 1 Requirements for sulfur and phosphorus contents in deposited metal of steel electrodes and rods for gas shielded arc welding of pressure equipment
3.4 Mechanical property and bend tests of deposited metal
3.4.1 The percentage elongation after fracture of the tensile specimen for deposited metal of steel electrodes and rods for gas shielded arc welding of pressure equipment shall meet the requirements of GB/T 8110 and shall not be less than 18%. See Annex B for the reference values of the tensile properties of deposited metal of stainless steel electrodes and rods.
3.4.2 See Table 2 for the impact test requirements for deposited metal of steel electrodes and rods for gas shielded arc welding of pressure equipment. The mean value of the impact test results shall not be less than those specified in Table 2, the impact test result of only one specimen is allowed to be less than the specified value but shall not be less than 70% of the latter.
Foreword II
1 Scope
2 Normative references
3 Technical requirements
4 Mechanical property and bend tests of deposited metal
5 Product Identification
Annex A (Informative) A comparison of stainless steel electrode models, and domestic and foreign designations and categories
Annex B (Informative) Tensile properties of the deposited metal of stainless steel electrodes and rods
