1 Scope
This standard specifies the preparation, sample preparation, inspection method and qualified indexes for pressure equipments (boiler, pressure vessels and pressure piping) product welded coupons.
This standard is applicable to the inspection of mechanical property and bending property for steel, aluminum, titanium, copper and nickel pressure equipments product welded coupons.
The product welded coupons include product weld test plate, product inspection coupons, simulating loop and certification loop.
This standard is not applicable to gas cylinders.
2 Normative Reference
The following referenced documents are indispensable references, only the edition cited applies. For dated references, only the dated edition of the normative reference referred to applies. For the undated normative references, the latest editions (including all amendments) apply.
GB/T 228 Metallic Materials-Tensile Testing
GB/T 229 Metallic Materials -Charpy Pendulum Impact Test Method
GB/T 2653 Bend Test Methods on Welded Joints
NB/T 47014 Welding Procedure Qualification for Pressure Equipment
3 General Provisions
3.1 In addition to the requirements of this standard, the inspection of mechanical property for product welded coupons shall also in accordance with the relevant requirements of safety technical codes, standards and design documents.
3.2 Materials used for coupons shall be of the same standard, code (mark and steel grade), specification (only for thickness and outside diameter) and heat treatment state with materials used for components of pressure equipments. Where 06Cr13Al steel is adopted to weld pressure equipments and post-weld heat treatment is not carried out, the base metal of coupons shall include steel plate of each furnace number.
3.3 The pressure equipments product welded coupons are classified into plate coupons and tubulous coupons. Tubulous refers to pipeline and loop.
3.4 The arrangement of product welded coupons:
a) The plate coupon of shell ring longitudinal joints shall be arranged at the prolongation of its welding line; it shall be welded simultaneously with the shell ring that it represents.
b) The tubulous coupons or plate coupons used for circumferential joints shall be welded in the welding process of components of pressure equipments which it represents.
3.5 Welding procedure of coupons
3.5.1 Where the inspected welded joints are subjected to different welding procedures, the welding procedure and condition of the coupons shall be the same with those of the welded joints that coupons represent; coupons shall be prepared with practical welding procedure (includes post-weld heat treatment) which can bring lower mechanical property.
3.5.2 Welders for welding the coupon shall be the one participates in welding the pressure equipments components.
3.5.3 Coupons shall be prepared according to the special welding process documents. Coupon code, work order number or pressure equipments number and material code shall be indicated clear in the welding process documents.
3.5.4 Coupons shall be equipped with welding records.
3.6 Repair coupon welding line is permissible and the repair process shall be the same with the repair process of pressure equipments components.
3.7 After being carried out appearance inspection and nondestructive testing, coupons shall be sampled at the position where free from defect and imperfection.
3.8 The sample shall be allowed for cool leveling before removing welded joint reinforcement.
3.9 Where two or more than two kinds of welding methods are adopted or welding procedure with different key factors and supplemental factors are adopted, all weld metal and heat affected zone shall be carried out mechanical property inspection and bending property inspection.
3.10 The following identification marks shall be made for the coupons:
a) Code of coupons;
b) Material mark number;
c) Welder code.
1 Scope
2 Normative Reference
3 General Provisions
4 Coupon Preparation
5 Samples and Category of Coupons Mechanical Property Inspection
6 Inspection Method and Qualified Indexes
7 Reinspection
