This part of GB/T 34020 specifies the classification and designation, dimensions, shape, weight and tolerances, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of double wall copper-brazed steel tubes used in tubing system for automobiles.
This part is applicable to double wall copper-brazed steel tubes used in the brake, clutch, power steering, fuel supply/return, engine, ventilation and cooling tubing systems of automobiles as well as double wall copper-brazed steel tubes (hereinafter referred to as "double wall tubes") used in mechanical and hydraulic tubing systems and general engineering 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 222 Permissible tolerances for chemical composition of steel products
GB/T 228.1-2010 Metallic materials - Tensile testing - Part 1: Method of test at room temperature
GB/T 241 Metal materials - Tube - Hydrostatic pressure test
GB/T 242 Metallic materials - Tube - Drift expanding test
GB/T 244 Metallic materials - Tube - Bend test
GB/T 246 Metallic materials - Tube - Flattening test
GB/T 682 Chemical reagent - Trichloromethane
GB/T 686 Chemical reagent - Acetone
GB/T 688 Chemical reagent - Carbon tetrachloride
GB/T 2102 Acceptance, packing, marking and quality certification of steel pipe
GB/T 2975 Steel and steel products - Location and preparation of samples and test pieces for mechanical testing
GB/T 7735-2016 Automated eddy current testing of seamless and welded (except submerged arc-welded) steel tubes for detection of imperfections
GB/T 34020.1 Double wall copper-brazed steel tubes - Part 1: Tubing system for refrigerator
YB/T 069 Copper-coated steel strips for welded pipe
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 34020.1 apply.
4 Classification and designation
4.1 See Table 1 for the states and codes of the outer surface of double wall tubes.
Table 1 States and codes of the outer surface of double wall tubes
GB/T 34020.2-2017 The following standards are cited：
