GB/T 20928-2020 Seamless inner grooved copper tube
1Scope
This standard specifies the classification,requirements,testing methods, inspection rules, packaging,marking, transportation, storage, quality certificate and order list (or contract) of seamlss innergrooved copper tube.
This standard is applicable to seamless inner grooved copper tube (hereinafter referred to as tube)for air conditioner and refrigerator units.
2 Normative references
The following referenced documents are indispensable for the application of this document.For datedreferences,only the edition cited applies.For undated references,the latest edition of the referenceddocument (including any amendments) applies.
GB/T 242,Metal materials Tube Drift-expanding test
GB/T 2828.1, Sampling procedures for inspection by attributes Part 1: Sampling schemes indexodby acceptance quality limit (AQL) for lot-by-lot inspection
GB/T 5121(all parts), Methods for chemical analysis of copper and copper alloysGB/T 5231, Dosignation and chemical composition of wrought copper and copper alloysGB/T 5248, Eloctromagnetic (eddy.curront) examination of copper and copper alloy scamlass tubeGB/T 8170, Rules of rounding off for numerical values& expression and judgoment of limiting valuesGB/T 8888, Wrough heavy non ferrous metal products-packing , marking , transportation , storing andcertificate of quality
GB/T 26303.1 , Moasuring method for dimensions and shapos of wrought copper and copper alloyPart 1: Tube
GB/T 34505, Copper and copper alloy materials-Tensile testing at room temperature
YS/T 347 ,Copper and copper alloys Estimation of average grain size
YS/'T 482 , Methods for analysis of copper and copper alloys The atomic emission spectrometry
YS/T 483, Mothod for analysis of copper and copper alloys-X-Ray fluorescence spectrometric( wavelength dispersive )
YS/T 668 , The sampling method of physical and chemical testing for copper and copper alloys
YS/'T 815 , Preparation method of test piecos for mechanical and technological properties of copperand copper alloys
3 Terms and definitions
For the purpose of this document,the following terms and definitions apply3.1
seamless inner grooved copper tube
a copper tube, which is smooth on the outer surface, with regular grooves of certain numbers on theinterior surface,and continuously circled on the cross section
3.2
weight per meter
the weight of inner grooved copper tube per meter,in gram per meter (g/m)
4Classification and designation
4.1 Classification
The designation, code, temper and form of delivery of the tubes shall meet the roquirements given inTable 1.The groove drawing is shown in Figure 1.$pecification range shall meet the requirements giv.en in Table 2. The inner diameter (l.D.) ,outer diameter( 0.D.) and coil height (width) of level woundcoil shall meet the roquirements given in Table 3.The recommended specifications are given in Annex A.
Product marking4.2
The tube dosignation shall be marked in the sequence of product name, the code of this standard,des-ignation, temper,0.D., bottom wall thickness, groove height, apex angle,helix angle and number ofgrooves.
EXAlMPLE 1 Right-handed inner grooved copper tube Lwc made of TP2 (C12200),ght snnesl (050), with the 0.D.ol9.52 mm, the bottom wall thickness of 0.30 mm,the groove height of 0.20 mm,apex angle of 53",helix angle of 18,60grooves is marked as:
1.G.T LWC GB'T 20928.TP2050 9.52 x0.30 + 0.20-53/18 60
Or IGT LWC GB'T 20928 C12200050.9.52 x0.30+0.20-53/18.60
EXAMPLE 2Left.handed inner grooved pisin tube made of Tu2 (T10180) with a length of 3 000 mm, soft anneal(060),the 0.D,of 7.00 mm, the bottom wall thickness of 0.27 mm, the groove height of 0.20 mm, apexangle of 53",helix angle of 18,60 grooves is marked as :
Inner grooved pigin tube GB/T 20928 TU2060-7.00 x0.27+ 0.20-53/L18.60 x 3 000OrInner grooved plain tube GB/T 20928-T10180060-7.00 x0.27 +0.20.53/L18 60 x 3 000
NOTE The defsult of direction of spiral is right.handed and the L is remarked for left.handed.
