This standard specifies the dimensions and allowable deviations of aluminum and aluminum alloy pipes. This standard applies to aluminum and aluminum alloy hot extruded seamless round tubes, cold drawn, rolled round tubes, cold drawn square tubes, rectangular tubes and oval tubes. This standard does not apply to aluminum and aluminum alloy pipes hot extruded by combined dies. The dimensional deviation of the pipes hot extruded by combined dies shall comply with the provisions of GB/T 14846 "Dimensional deviation of aluminum and aluminum alloy extruded profiles". GB/T 4436-1995 Dimensions and allowable deviations of aluminum and aluminum alloy pipes GB/T4436-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Wrought aluminium and aluminium alloy tubes-Dimensions and deviations
Subject and scope of application
This standard specifies the dimensions and deviations of aluminium and aluminium alloy tubes. GB/T4436-1995
Replaces GB4436:84
This standard applies to aluminium and aluminium alloy hot extruded seamless round tubes, cold drawn, rolled round tubes, cold drawn square tubes, rectangular tubes and oval tubes. This standard is not applicable to aluminium and aluminium alloy tubes hot extruded by combined dies. The dimensional deviations of tubes hot extruded by combined dies shall comply with the provisions of GB/T14846 "Dimensional deviations of aluminium and aluminium alloy extruded profiles". H
2 Specifications
2.1 The specifications of extruded round tubes (cross section as shown in Figure 1) are shown in Table 1. Approved by the State Administration of Technical Supervision on April 18, 199556
Implementation on December 1, 1995
GB/T 4436
—1995
GB/T 4436-1995
Continued Table 1
GB/T4436—1995
Continued Table 1
Note: The blank area indicates the available specifications. If other specifications are required, both parties can negotiate. 2 The specifications of cold-drawn and rolled round tubes (cross-section shown in Figure 1) are shown in Table 2. 2.2
GB/T 4436-1995
GB/T4436-1995
Continued Table 2
Note: The blank area indicates the available specifications. If other specifications are required, both parties can negotiate. 2.5
2.3 Specifications of cold drawn square tubes (section shown in Figure 2) are shown in Table 3. Thickness
Nominal side length
GB/T4436—1995
Note: The blank area indicates the available specifications. Other specifications can be negotiated by both parties. 2.4 Specifications of cold drawn rectangular tubes (section shown in Figure 3) are shown in Table 4. 62
Nominal side length
14×10
16×12
18×10
18×14
20×12
22×14
25×15
28×16
32×18
36×28
40×25
45×30
50×30
55×40
GB/T 4436—1995
Note: Blank area indicates available specifications. Other specifications can be negotiated by both parties. 2.5
2.5 Specifications of cold drawn oval tube (section as shown in Figure 4) are shown in Table 5. Thickness
Major axis (a)
3 Permissible deviation of overall dimensions
3.1 Permissible deviation of overall dimensions of extruded round tube GB/T4436—1995
Minor axis (6)
3.1.1 Permissible deviation of outer diameter of extruded round tube is shown in Table 6.64
Nominal outer diameter
≥25～50
>50～100
>100～150|| tt||>150～200
>200~～250
>250～300
300～350
>350~400
Ordinary grade (grade)
Permissible deviation of any outer diameter from nominal
outer diameter
High magnesium alloy
GB/T4436--1995
Permissible deviation of any outer diameter from nominal
outer diameter
Other alloys
High magnesium and gold
High precision Grade (G)
Other alloys
Permissible deviation between average outer diameter and nominal
Outer diameter
High magnesium alloys
Note: ①) When the product standard or contract requires the diameter deviation to be all (+) or all (-), the deviation value shall be twice the corresponding value in the above table; mm
Other alloys
②When the required diameter deviation is the inner diameter, the corresponding outer diameter deviation value in Table 6 shall be taken as the inner diameter deviation according to the outer diameter of the pipe, and the words "diameter deviation requires inner diameter\" shall be indicated in the contract; ③Any one of Table 6 The outer diameter refers to the outer diameter measured at any point on the cross section of the pipe; the average outer diameter refers to the average value of two outer diameters at right angles to each other measured at any point on the cross section of the pipe, such as 1/2 (AB+CD) in Figure 1; ① High magnesium alloy refers to aluminum-magnesium alloys with an average magnesium content greater than or equal to 3% in the chemical composition (such as LF3, LF5, 5056 alloy, etc.). The allowable deviation of the wall thickness of the extruded round tube is shown in Table 7. 3.1.2
Allowable deviation of average wall thickness and nominal wall thickness, mm Any wall thickness and
Nominal wall thickness
>6.0～10. 0
>10. 0~~12. 0
12. 0~ 20. 0
>20.0~25.0
>25. 0~38. 0
38. 0~50. 0
Average wall thickness
Allowable deviation
Average wall thickness
Maximum value
Nominal outer diameter, mm
>30～75
>75～125
Other alloys
High magnesium alloysOther alloysHigh magnesium alloysOther alloysHigh magnesium alloysOther alloysHigh magnesium alloys+0.54
Nominal wall thickness
>6.0~10.0
>10.0~12.0
>12. 0~20. 0www.bzxz.net
>20. 0~~25. 0
>25.0～38.0
38. 0~~50. 0
Permitted deviation of any wall thickness from
average wall thickness
Maximum value of average wall thickness
GB/T4436—1995
Continued Table 7
Permitted deviation of average wall thickness from nominal wall thickness, mm Nominal outer diameter, mm
High magnesium alloy
Other alloys
>30～75
75～125
High magnesium alloyOther alloysHigh magnesium alloyOther alloysHigh magnesium alloyOther alloys±0.36
Note: ① When the specified size 1. When the dimensions are the outer diameter and the inner diameter instead of the wall thickness itself, the wall thickness deviation only checks the allowable deviation between any wall thickness and the average wall thickness; 2. When the product standard or contract requires that the thickness deviation is all (10) or all (1), the deviation value is twice the corresponding value in the above table; 3. Any wall thickness in Table 7 refers to the wall thickness measured at any point on the pipe section; the average wall thickness refers to the average value of the wall thickness measured at both ends of any outer diameter of the pipe section, such as 1/2 (AE+BF) in Figure 1; 4. High magnesium alloy refers to aluminum-magnesium alloys (such as L.F3, 1.F5, 5056 alloy, etc.) whose average magnesium content in the chemical composition is greater than or equal to 3%. 3.1.3 The curvature of the extruded round tube is shown in Table 8. Table 8
Nominal outer diameter
25～150
>150～250
Per meter length
Ordinary grade
Total length (L meters))
Bending degree, not more than
High precision grade
Per meter length
Total length (1 meter)
Ultra-high precision grade
Per meter length
Golden length () meters
Note: Table 8 is not applicable to annealed pipes. For annealed pipes and pipes with an external diameter of more than 250mm, if there is a requirement for bending degree, it should be indicated in the contract.
3.1.4 The fixed and unfixed length range of extruded round pipes is 300~～5800mm. The allowable deviation of the length of the fixed-length pipe is +15mm. For the pipe supplied in double length, a 5mm sawing margin should be left for each sawing. 3.1.5 The two ends of the extruded round tube should be cut evenly and there should be no burrs on the ends. 3.2 The allowable deviation of the outer dimensions of cold-drawn and rolled round tubes is 3.2.1 The allowable deviation of the outer diameter of cold drawn and rolled round tubes is shown in Table 9. 66
Nominal outer diameter
6～12
>12～25
25～50
50-~75
>75～120
6-1995
GB/T 4436
Ordinary grade (±)
Allowable deviation of any outer diameter from nominal outer diameter Annealed
Average outer diameter from nominal
Allowable deviation of outer diameter
All pipes
High precision grade (upper)
Any outer diameter from nominal
Allowable deviation of outer diameter
Average outer diameter from nominal
Allowable deviation of outer diameter
All pipes
Note: () When product standard Or when the contract requires that the diameter deviation is all (+) or all (-), the deviation value is twice the corresponding value in the above table. Any outer diameter in Table 9 refers to the outer diameter measured at any point on the pipe section; the average outer diameter refers to the average value obtained by measuring two outer diameters at right angles to each other on the pipe section, such as 1/2 (AB + CD) in Figure 1. ③ High magnesium tube refers to aluminum-magnesium alloy (such as L.F3, 1.F5.5056 alloy, etc.) tubes with an average magnesium content greater than or equal to 3% in the chemical composition. ④ When the pipe is both annealed and high magnesium, its deviation is determined according to the annealed pipe. The allowable wall thickness deviation of cold-drawn and cold-rolled round pipes is shown in Table 10. 3.2.2
Nominal wall thickness
Ordinary grade
High precision grade
≥1.2~2.0
2.0~3.0
>3.0~4.0
>4.0~5.0
>0.8~~1.2
1.2~2.0
2.0~3.0
3.0~4.0
4.0--5, 0
Permissible deviation between average wall thickness and nominal
Permissible deviation between any wall thickness and nominal wall thickness, mm high magnesium tube
unquenched tube
two 0. 14
Other pipes
Quenched pipes
Not exceeding nominal wall thickness+15%
Minimum value±0.12
Not exceeding nominal wall thickness=10%
Minimum value±008
Note: () When the specified size is the outer diameter and inner diameter instead of the wall thickness itself, the items in Table 10 are not checked. Only the deviation value between the arbitrary wall thickness and the semi-average wall thickness is checked. The high-precision grade is 10% of the nominal wall thickness, and the ordinary grade is ±15% of the nominal wall thickness. (②) When the product standard or contract requires that the wall thickness deviation is all (+) or all (), the deviation value is twice the corresponding value in the above table. ③) Any wall thickness in Table 10 refers to the wall thickness measured at any point on the pipe section; the average wall thickness refers to the average value of the wall thickness measured at any two ends of the outer diameter of the pipe section, such as 1/2 (AF+BF) in Figure 1.
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