Inside Diameter Required Precision Seamless Steel Tube for Hydraulic and Pneumatic Cylinder Use
液压和气动缸筒用精密内径无缝钢管
This standard is applicable to the manufacturing of cold-drawn or cold-rolled precision seamless steel tube with precise inside diameter for hydraulic and pneumatic cylinder use.
1 Dimension, Diameter and Weight
1.1 Outside and inside diameter dimension
The outside and inside diameter dimension of steel tube shall comply with those specified in "Seamless Cold-drawn or Cold-rolled Steel Tubes for Precision Applications" (GB 3639-83).
Table 1 shows the preferred dimension series for bore diameter of cylinder tube and is for reference in design and manufacturing.
1.2.2.1 The inside diameter tolerance of the steel tube is based on the requirements in "Tolerance and Fitting Dimensions up to 500mm Holes Shaft Tolerance Range and Fitting" (GB 1801-79) and divided into 3 grades (H8, H9 and H10). See Table 3 for their values.
Table 3
Nominal inside diameter dimension, mm Tolerance range, μm
H8 H9 H10
>3~6 +18
0 +30
0 +48
0
>6~10 +22
0 +36
0 +58
0
>10~18 +27
0 +43
0 +70
0
>18~30 +33
0 +52
0 +84
0
>30~50 +39
0 +62
0 +100
0
>50~80 +46
0 +74
0 +120
0
>80~120 +54
0 +87
0 +140
0
>120~180 +63
0 +100
0 +160
0
>180~250 +72
0 +115
0 +185
0
1.2.2.2 Only if the ratio of inside diameter to wall thickness of steel tube is less than or equal to 20:1, the steel tube with tolerance of H8 or H9 may be normally provided, which shall be noted in the order contact.
1.2.2.3 As required by the demander, noted in the contract, the steel tube with bi-directional deviation (same tolerance) may be provided.
1.2.3 Irregularity of wall thickness
In the case that the steel tube is provided on the basis of outside and inside diameter dimension, the irregularity of wall thickness of it shall guarantee that the minimum wall thickness of the tube shall not excess 10% of the minimum nominal wall thickness decided by diameter tolerance. Namely:
Where,
tmin- the permissible minimum wall thickness of steel tube, mm;
Dmin- the permissible minimum outside diameter of steel tube, mm;
dmax- the permissible maximum inside diameter of steel tube, mm.
In the case that the steel tube is provided on the basis of inside diameter and wall thickness, the measured wall thickness at any cross section along length direction of the steel tube shall not deviate from ±10% above of the nominal wall thickness (including irregularity of wall thickness).
1.3 Curvature (straightness)
The curvature of steel tube is classified into three grades:
Grade A - 0.3:1000
Grade B - 1.0:1000
Grade C - 1.5:1000
Grade A or Grade B steel tube can be provided only if the Parties negotiate with each other and noted in the contract.
1.4 Length
1.4.1 Typical length
Generally, steel tube is delivered on the basis of typical length (2~6m).
1.4.2 Specified length
Within the range of typical length, the permissible total length deviation of specified length (including the deviation caused by possible non-vertical tube end) is:
For steel tube length larger than 2~5m; its tolerance is: mm;
For steel tube length larger than 5~6m; its tolerance is: mm.
1.5 End shape
The burrs on both end cuts of the steel tube shall be cleaned up.
1.6 Weight
1.6.1 The steel tube is delivered on the basis of actual weight.
1.6.2 The steel tube with specified length may be delivered on the basis of theoretical weight. The steel tube weight per meter is calculated according to the following formula (steel density is 7.85):
W=0.02466·s (D-s)
Where,
W - the theoretical weight of steel tube per meter, kg/m;
s - the nominal wall thickness of steel tube, mm;
D - the nominal outside diameter of steel tube, mm.
The calculation for theoretical weight of steel tube is on the basis of rounded off method with reserving two digits behind decimal point.
For the permissible deviation of theoretical weight, the single steel tube is ±10%, the batched 10t above weighted tube is ±7.5%.
1.7 Marking example
Cold-rolled seamless steel tube delivered by typical length, 54mm outside diameter, 50mm inside diameter, made of No.20 steel, H8 inside diameter tolerance, inner surface roughness of Grade D:
Precision-rolled tube 20-φ54×φ50 H8, d-GB 8713-88
2 Technical Requirements
2.1 Manufacturing method
2.1.1 Smelting method of steel
Steels may be smelted in electric arc furnace, open hearth furnace, pure oxygen top-blown converter through external refining process.
2.1.2 Manufacturing method of steel tube
The steel tube shall be made with cold-drawn or cold-rolled seamless manufacturing method. The method designated by the demander shall be noted in the contract.
2.2 Designation and chemical composition
Steel tube shall be rolled with No.10, 20, 35 and 45 steel. The chemical composition (smelting composition) shall meet those specified in "Carbon Constructional Quality Steel - Technical Conditions" (GB 699-88). The steel tube is accepted on the basis of smelting composition. If the product analysis is needed, the permissible deviation of analysis composition and smelting composition of the finished steel tube shall comply with the relevant requirements of "Method of Sampling Steel for Determination of Chemical Composition and Permissible Variations for Product Analysis" (GB 222-84).
Upon negotiation between the Parties, the tube may be made of other steel.
2.3 Delivery condition
The steel tube is delivered in cold-working/hard (Y) condition. If necessary, it may also be delivered in heat treatment condition upon negotiation between the Parties.
2.4 Mechanical performance
The mechanical performance of the steel tube in delivery shall meet those specified in "mechanical performance under cold-working/hard (Y) condition" of Table 3 in GB 3639-83.
2.5 Inner surface roughness
2.5.1 The inner surface of the steel tube is based on those specified in "Surface Roughness Parameters and Their Values" (GB 1031-83). The surface roughness value is the No.1 series of contour arithmetic average deviation Ra.
2.5.2 The inner surface roughness grade shall be in accordance with those specified in Table 4.
Table 4
Grade a b c d e f
Nominal value of Ra, μm 0.125 0.2 0.4 0.8 1.6 3.2
Generally, Grade “f” and Grade “e” steel is adopted for cold-drawn steel tube and cold-rolled steel tube respectively. The permissible deviation is +25% of nominal value Ra; if other grades steel tube is adopted, it shall be noted in the contract.
The local defect (like dent and scratch) shall not have an impact on the calculation of surface roughness. These local defects are determined according to visual inspection or other proper methods.
2.5.3 The maximum local defect depth of the inner surface of steel tube shall be in accordance with those specified in Table 5.
Table 5
Outside diameter mm Permissible maximum depth of the defect, μm
Scratch or dent
≤63 20
>63 while ≤112 40
>112 50
2.5.4 For the steel tube delivered in cold-drawn condition, the phosphate lubricant produced in manufacturing process is allowable adhered at its inner surface.
2.6 External surface quality
The external surface of steel tube shall be free from any crack, wrinkle, scar, peeling or crack. These defects shall be entirely cleaned up and after cleaning, the minimum wall thickness of steel tube shall meet those specified in Article 1.2.3. Other minor defect with depth not exceeding 4% of wall thickness is allowed but the maximum depth shall not exceed 0.20mm.
1 Dimension, Diameter and Weight 2 Technical Requirements 3 Test Method 4 Inspection Rule 5 Packaging, Marking and Quality Certificate Additional Explanation
Inside Diameter Required Precision Seamless Steel Tube for Hydraulic and Pneumatic Cylinder Use
液压和气动缸筒用精密内径无缝钢管
This standard is applicable to the manufacturing of cold-drawn or cold-rolled precision seamless steel tube with precise inside diameter for hydraulic and pneumatic cylinder use.
1 Dimension, Diameter and Weight
1.1 Outside and inside diameter dimension
The outside and inside diameter dimension of steel tube shall comply with those specified in "Seamless Cold-drawn or Cold-rolled Steel Tubes for Precision Applications" (GB 3639-83).
Table 1 shows the preferred dimension series for bore diameter of cylinder tube and is for reference in design and manufacturing.
Table 1
In mm
Inside diameter Wall thickness
1.5 2.0 2.5 3.0 3.5 5.0 6.0 7.5 10.0 12.5 15.0 20.0
Outside diameter
25 28 — — 31 — 35 — 40 — — — —
32 35 36 — 38 — 42 — 47 — — — —
40 — — 45 46 — 50 — 55 — — — —
50 — — 55 56 — 60 — 65 70 75 — —
63 — — 68 69 — 73 75 78 83 88 — —
80 — — 85 86 — 90 92 95 100 105 110 —
100 — — 105 106 — 110 112 115 120 125 130 —
125 — — — — 132 135 137 140 145 160 155 165
160 — — — — 165 170 — 175 180 185 190 200
200 — — — — — 220 — 215 220 225 230 240
1.2 Permissible dimension deviation
1.2.1 Permissible outside diameter deviation
The permissible outside diameter deviation of steel tube shall meet those specified in Table 2 and the ovality shall be included.
Upon request of the demander, unidirectional deviation with the same tolerance may be provided.
Table 2
In mm
Outside diameter Permissible deviation Outside diameter Permissible deviation
>0~30 ±0.10 >140~150 ±0.75
>30~40 ±0.15 >150~160 ±0.80
>40~50 ±0.20 >160~170 ±0.85
>50~60 ±0.25 >170~180 ±0.90
>60~70 ±0.30 >180~190 ±0.95
>70~80 ±0.35 >190~200 ±1.00
>80~90 ±0.40 >200~210 ±1.05
>90~100 ±0.45 >210~220 ±1.10
>100~120 ±0.50 >220~280 ±1.15
>120~140 ±0.65 >230~240 ±1.20
1.2.2 Inside diameter tolerance
1.2.2.1 The inside diameter tolerance of the steel tube is based on the requirements in "Tolerance and Fitting Dimensions up to 500mm Holes Shaft Tolerance Range and Fitting" (GB 1801-79) and divided into 3 grades (H8, H9 and H10). See Table 3 for their values.
Table 3
Nominal inside diameter dimension, mm Tolerance range, μm
H8 H9 H10
>3~6 +18
0 +30
0 +48
0
>6~10 +22
0 +36
0 +58
0
>10~18 +27
0 +43
0 +70
0
>18~30 +33
0 +52
0 +84
0
>30~50 +39
0 +62
0 +100
0
>50~80 +46
0 +74
0 +120
0
>80~120 +54
0 +87
0 +140
0
>120~180 +63
0 +100
0 +160
0
>180~250 +72
0 +115
0 +185
0
1.2.2.2 Only if the ratio of inside diameter to wall thickness of steel tube is less than or equal to 20:1, the steel tube with tolerance of H8 or H9 may be normally provided, which shall be noted in the order contact.
1.2.2.3 As required by the demander, noted in the contract, the steel tube with bi-directional deviation (same tolerance) may be provided.
1.2.3 Irregularity of wall thickness
In the case that the steel tube is provided on the basis of outside and inside diameter dimension, the irregularity of wall thickness of it shall guarantee that the minimum wall thickness of the tube shall not excess 10% of the minimum nominal wall thickness decided by diameter tolerance. Namely:
Where,
tmin- the permissible minimum wall thickness of steel tube, mm;
Dmin- the permissible minimum outside diameter of steel tube, mm;
dmax- the permissible maximum inside diameter of steel tube, mm.
In the case that the steel tube is provided on the basis of inside diameter and wall thickness, the measured wall thickness at any cross section along length direction of the steel tube shall not deviate from ±10% above of the nominal wall thickness (including irregularity of wall thickness).
1.3 Curvature (straightness)
The curvature of steel tube is classified into three grades:
Grade A - 0.3:1000
Grade B - 1.0:1000
Grade C - 1.5:1000
Grade A or Grade B steel tube can be provided only if the Parties negotiate with each other and noted in the contract.
1.4 Length
1.4.1 Typical length
Generally, steel tube is delivered on the basis of typical length (2~6m).
1.4.2 Specified length
Within the range of typical length, the permissible total length deviation of specified length (including the deviation caused by possible non-vertical tube end) is:
For steel tube length larger than 2~5m; its tolerance is: mm;
For steel tube length larger than 5~6m; its tolerance is: mm.
1.5 End shape
The burrs on both end cuts of the steel tube shall be cleaned up.
1.6 Weight
1.6.1 The steel tube is delivered on the basis of actual weight.
1.6.2 The steel tube with specified length may be delivered on the basis of theoretical weight. The steel tube weight per meter is calculated according to the following formula (steel density is 7.85):
W=0.02466·s (D-s)
Where,
W - the theoretical weight of steel tube per meter, kg/m;
s - the nominal wall thickness of steel tube, mm;
D - the nominal outside diameter of steel tube, mm.
The calculation for theoretical weight of steel tube is on the basis of rounded off method with reserving two digits behind decimal point.
For the permissible deviation of theoretical weight, the single steel tube is ±10%, the batched 10t above weighted tube is ±7.5%.
1.7 Marking example
Cold-rolled seamless steel tube delivered by typical length, 54mm outside diameter, 50mm inside diameter, made of No.20 steel, H8 inside diameter tolerance, inner surface roughness of Grade D:
Precision-rolled tube 20-φ54×φ50 H8, d-GB 8713-88
2 Technical Requirements
2.1 Manufacturing method
2.1.1 Smelting method of steel
Steels may be smelted in electric arc furnace, open hearth furnace, pure oxygen top-blown converter through external refining process.
2.1.2 Manufacturing method of steel tube
The steel tube shall be made with cold-drawn or cold-rolled seamless manufacturing method. The method designated by the demander shall be noted in the contract.
2.2 Designation and chemical composition
Steel tube shall be rolled with No.10, 20, 35 and 45 steel. The chemical composition (smelting composition) shall meet those specified in "Carbon Constructional Quality Steel - Technical Conditions" (GB 699-88). The steel tube is accepted on the basis of smelting composition. If the product analysis is needed, the permissible deviation of analysis composition and smelting composition of the finished steel tube shall comply with the relevant requirements of "Method of Sampling Steel for Determination of Chemical Composition and Permissible Variations for Product Analysis" (GB 222-84).
Upon negotiation between the Parties, the tube may be made of other steel.
2.3 Delivery condition
The steel tube is delivered in cold-working/hard (Y) condition. If necessary, it may also be delivered in heat treatment condition upon negotiation between the Parties.
2.4 Mechanical performance
The mechanical performance of the steel tube in delivery shall meet those specified in "mechanical performance under cold-working/hard (Y) condition" of Table 3 in GB 3639-83.
2.5 Inner surface roughness
2.5.1 The inner surface of the steel tube is based on those specified in "Surface Roughness Parameters and Their Values" (GB 1031-83). The surface roughness value is the No.1 series of contour arithmetic average deviation Ra.
2.5.2 The inner surface roughness grade shall be in accordance with those specified in Table 4.
Table 4
Grade a b c d e f
Nominal value of Ra, μm 0.125 0.2 0.4 0.8 1.6 3.2
Generally, Grade “f” and Grade “e” steel is adopted for cold-drawn steel tube and cold-rolled steel tube respectively. The permissible deviation is +25% of nominal value Ra; if other grades steel tube is adopted, it shall be noted in the contract.
The local defect (like dent and scratch) shall not have an impact on the calculation of surface roughness. These local defects are determined according to visual inspection or other proper methods.
2.5.3 The maximum local defect depth of the inner surface of steel tube shall be in accordance with those specified in Table 5.
Table 5
Outside diameter mm Permissible maximum depth of the defect, μm
Scratch or dent
≤63 20
>63 while ≤112 40
>112 50
2.5.4 For the steel tube delivered in cold-drawn condition, the phosphate lubricant produced in manufacturing process is allowable adhered at its inner surface.
2.6 External surface quality
The external surface of steel tube shall be free from any crack, wrinkle, scar, peeling or crack. These defects shall be entirely cleaned up and after cleaning, the minimum wall thickness of steel tube shall meet those specified in Article 1.2.3. Other minor defect with depth not exceeding 4% of wall thickness is allowed but the maximum depth shall not exceed 0.20mm.
Contents of GB/T 8713-1988
1 Dimension, Diameter and Weight
2 Technical Requirements
3 Test Method
4 Inspection Rule
5 Packaging, Marking and Quality Certificate
Additional Explanation
