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1. Scope
This standard specifies the metal pipes for tubing mainly used for brakes, fuel and lubrication of automobiles (hereinafter referred to as the “pipes”).
Remarks:
The applicable standards for this standards are shown below.
JIS G3141 Cold rolled carbon steel sheets and strip
JIS G3445 Carbon steel tubes for machine structural purposes
JIS G 3472 Electric resistance welded carbon steel tubes for automobile structural purposes
JIS H 3300 Copper and copper alloy seamless pipes and tubes
JIS Z 2241 Method of tensile test for metallic materials
JIS Z2244 Method of vickers hardness test
JIS Z2251 Method of micro hardness test for vickers and knoop hardness
JASO M 104 Testing method for automobile brake tube
2. Classification
2.1 Type of pipe
The pipes shall be classified into the following 4 groups:
Table 1 Pipes for automobile tubing
| Type | Code | Example of application |
| Brazed double wall low carbon steel tubing | TDW | Tubing mainly for brakes |
| Welded low carbon steel tubing | TSW | Tubing mainly for fuel and lubircation |
| Carbon steel tubes for machine structural purposes | STKM 11J | Tubing for cooling etc. |
| Copper and copper alloy seamless pipes and tubes | C1201 or C1220 | Tubing mainly for air brakes |
2.2 Classification of surface treatment
The pipes shall be classified as tabulated below, according to the types of surface treatment:
Table 2 Surface Treatment
| Type | |||||||||
| Without surface treatment | Dipped tin-lead alloy coating | Electrolytic zinc coating | Organic film on electrolytic zinc coating | ||||||
| 8μm | 13μm | 25μm | 8μm | 13μm | 25μm | ||||
| Brazed double wall low carbon steel tubing | TDW | -N | -T | -Z8 | -Z13 | -Z25 | -Z8-OC | -Z13-OC | -Z25-OC |
| Welded low carbon steel tubing | TSW | -N | -T | -Z8 | -Z13 | -Z25 | -Z8-OC | -Z13-OC | -Z25-OC |
| Carbon steel tubes for machine structural purposes | STKM 11J | -N | -T | -Z8 | -Z13 | -Z25 | |||
| Copper and copper alloy seamless pipes and tubes | C1201 or C1220 | ||||||||
3. Quality
3.1 Appearance
Both inside and outside of the finished tubing shall be smooth and free from cracks, flaws or rusts.
3.2 Chemical composition
Chemical composition of the tubing shall be pursuant to JIS G3141, JIS G3445, JIS G 3472, and JIS H 3300.
3.3 Mechanical property
Mechanical property of the pipes shall be pursuant to Table 3.
Table 3 Mechanical Property
| Type | Code | Tensile strength MPa | Yield point MPa | Elongation % | Hardness HV | Bending expansion, flat bending |
Brazed double wall low carbon steel tubing | TDW | Not less than 294 | Not less than 176 | Not less than 25 | Not more than HV150 | Wall of the tubing shall be free from flaws or cracks after the tests pursuant to Table 10 are conducted |
| Welded low carbon steel tubing | TSW | |||||
| Carbon steel tubes for machine structural purposes | STKM 11J | Not less than 294 | Not less than 30 | |||
| Copper and copper alloy seamless pipes and tubes | C1201 or C1220 | Not less than 206 | Not less than 40 |
3.4 Surface Treatment
(1) Thickness of surface treatment shall be pursuant to Table 4 and Table 5.
Table 4 Thickness of inside surface treatment
| Type | Code | Thickness of inside surface treatment |
| Brazed double wall low carbon steel tubing | TDW | As is copper-coated for fusion process |
| Welded low carbon steel tubing | TSW | Copper coating not less than 3μm |
| Carbon steel tubes for machine structural purposes | STKM 11J | – |
| Copper and copper alloy seamless pipes and tubes | C1201 or C1220 | – |
Table 5 Thickness of outside surface treatment
| Type | Thickness of outside surface treatment | ||||||
| Dipped tin-lead alloy coating | Electrolytic zinc coating | Organic film on electrolytic zinc coating | |||||
| Z8 | Z13 | Z25 | Z8-OC | Z13-OC | Z25-OC | ||
| Brazed double wall low carton steel tubing | Average 6μm, minimum 3μm | Not less than 8μm | Not less than 13μm | Not less than 25μm | Zinc coating not less than 8μm | Zinc coating not less than 13μm | Zinc coating not less than 25μm |
| Organic film average 20μm minimum 10μm | |||||||
| Welded low carbon steel tubing | Zinc coating not less than 8μm | Zinc coating not less than 13μm | Zinc coating not less than 25μm | ||||
| Organic film average 20μm minimum 10μm | |||||||
| Carbon steel tubes for machine structural purpose | – | ||||||
| Copper and copper alloy seamless pipes and tubes | No treatment shall be required | ||||||
(2) Corrosion resistance
The test shall be conducted pursuant to corrosion test specified in Table 10 and shall meet requirements in Table 6.
Table 6 Corrosion Resistance
| Type and code of coating | Criteria | ||
| Time elapsed till formation of white corrosion product (hr) | Time elapsed till form rust (red rust) (hr) | ||
| Electrolytic zinc coating | Z8 | 72 | 192 |
| Z13 | 72 | 288 | |
| Z25 | 72 | 480 | |
| Dipped tin-lead alloy coating | T | Iron rust (red rust) shall appear 5 spots or less per 50 cm2 in 24 hours. | |
| Organic film on electrolytic zinc coating | Z8-OC | – | 2000 |
| Z13-OC | 2500 | ||
| Z25-OC | 3000 | ||
(3) Performance of organic film
Performance of organic film shall be pursuant to Table 6 and shall meet requirements in Table 7, after the tests pursuant to Table 10 are conducted as occasion demands.
Table 7 Performance of organic film
| Test Items | Criteria |
| Bending test | No flaking, cracking, and wrinkles shall occur. |
| Chipping test | No conspicuous flaking and cracking shall occur. |
| Heat cycle test | No blisters and flaking shall occur. |
| Warm water test | No blisters, flaking, cracking, and dissolution shall occur. |
| Fluid resistance test | No blisters, flaking, cracking , and dissolution shall occur. |
| Ozone resistance test | No flaking and cracking shall occur. |
3.5 Guarantee pressure and burst pressure
The pipes shall be tested pursuant to Table 10 and shall resist the guarantee pressure specified in Table 8 without leaving injurious deformation.
Table 8 Guarantee pressure and burst pressure
| Type | Code | Nominal diameter | Guarantee pressure MPa | Burst pressure MPa |
| Brazed double wall low carbon steel tubing | TDW | <4.76 6 and 6.35 8 10 | 34.3 34.3 24.5 24.5 | 108 83.3 66.2 53.9 |
| Welded low carbon steel tubing | TSW | <6.35 8-10 11-15 16-22.2 | 24.5 19.3 14.7 9.8 | – |
| Carbon steel tubes for machine structural purposes | STKM 11J | |||
| Copper and copper alloy seamless pipes and tubes | C1201 or C1220 | Pursuant to JIS H 3300 | ||
Table 9 Nominal diameter and dimension
| Nominal diameter | Outside diameter | Thickness | Tolerance | ||||
| Standard dimension | Tolerance | Standard dimension | |||||
| Brazed double wall low carbon steel tubing | Welded low carbon steel tubing | Carbon steel tubes for machine structural purposes | Copper and copper alloy seamless tubes | ||||
| 3.17 | 3.17 | +/-0.08 | 0.7 | 0.7 | 0.08 | +/-0.08 | |
| 4 | 4 | 0.7 | 0.7 | ||||
| 4.76 | 4.76 | 0.7 | 0.7 | 0.08 | |||
| 6 | 6 | 0.7 | 0.7 | ||||
| 6.35 | 6.35 | 0.7 | 0.7 0.8 | 0.08 | |||
| 8 | 8 | +/-0.1 | 0.7 | 0.7 0.8 1.0 | 0.7 0.8 1.0 | 1.0 | +/-0.1 |
| 9 | 9 | 1.0 | 1.0 | ||||
| 10 | 10 | 0.7 | 0.7 0.8 1.0 | 0.7 0.8 1.0 | 1.0 | ||
| 11 | 11 | – | 0.8 1.0 | ||||
| 12 | 12 | 0.9 1.0 | 0.9 1.0 | 1.0 | |||
| 12.7 | 12.7 | 0.9 1.0 | 0.9 1.0 | 1.0 | |||
| 14 | 14 | 1.0 | 1.0 | ||||
| 15 | 15 | 1.0 | 1.0 | 1.0 | |||
| 16 | 16 | 1.0 | 1.0 1.2 | ||||
| 17 | 17 | 1.0 | 1.0 1.2 | ||||
| 18 | 18 | 1.0 1.2 | 1.0 | ||||
| 19 | 19 | 1.0 1.2 | |||||
| 20 | 20 | 1.0 1.2 | 1.0 | ||||
| 21 | 21 | 1.0 1.2 | |||||
| 22 | 22 | 1.0 1.2 | 1.0 | ||||
| 22.2 | 22.2 | 1.0 1.2 | |||||
Table 10 Test Method
| Item | Type | ||||||||||
| Brazed double wall low carbon steel tubing | Welded low carbon steel tubing | Carbon steel tubes for machine structural purpose | Copper and copper alloy seamless pipes and tubes | ||||||||
| Tensile test | Pursuant to JIS Z2241 (Method of Tensile Test for Metallic Materials). | ||||||||||
| Bending test | Example if any flaws, cracks, or other defects occurred or not when the pipe was bent 360 degrees around a cylinder having the radius as specified below.
| – | |||||||||
| Expansion test | (1) Length of test specimen shall be 100 mm. (2) Examine if any flaws and cracks occurred or not when a conic tool with 1/10 taper was plugged into one end of the specimen and the specimen was expanded until the diameter of end face was increased by 20%. | (1) Length of test specimen shall be 100 mm. (2) Examine if any flaws and cracks occurred or not when a conic tool with angle of 60 degrees was plugged into one end of the specimen and the specimen was expanded until the diameter of end face was increased by 20%. | Pursuant to JIS H 3300 | ||||||||
| Developing test | – | (1) Length of test specimen shall be 100 mm. (2) Example if any injurious defects such as cracks and flaking occurred to the weld or not when the test specimen is split longitudinally at 90 degrees on each side of the weld and developed to form a flat plate. | – | ||||||||
| Flattening and bending test | (1) Length of test specimen shall be 100 mm. (2) Examine if any flaws and cracks occurred or not when the specimen is held between parallel plates, which are pressed in such a manner as the inside of tube comes to a close contact to make the specimen flat, and the flat specimen is once bent 90 degrees to the direction of axis around a cylinder having a diameter of 3 times the wall thickness of the tube and then stretched straight. | ||||||||||
| Flattening Test | (1) Length of test specimen shall be 100 mm. (2) Examine if any flaws and cracks occurred or not when the specimen is held between parallel plates, which are pressed in such a manner as the distance between the plates comes to 3 times the wall thickness of the tube. When the plates are pressed, the weld of tube shall be placed at 90 degrees to the direction of applied force. | Pursuant to JIS H 3300 | |||||||||
| Guarantee pressure test | Examine if any leak of other defects occurred or not when pipe is applied with specified hydraulic pressure and held for 5 minutes. | – | |||||||||
| Burst pressure test | Pursuant to 5.10 specified in JASO M104. | – | |||||||||
| Surface treatment thickness test | The standard practice shall be microscopic test. | – | |||||||||
| Corrosion resistance test | Pursuant to 5.6, Neutral salt water spray test, specified in JASO M104. | – | |||||||||
| Film performance test | Pursuant to 5. (test method) specified in JASO M104. | – | |||||||||
| Hardness test | Pursuant to JIS Z2244 or JIS Z2251 | – | |||||||||
4. Method of manufacturing
4.1 Method of manufacturing the brazed double wall low carbon steel pipes
The brazed double wall low carbon steel pipes shall be made by copper-coating both surfaces of SPCC specified in JIS G3141, shaping them into the form of double wall tubing, and sealing the seams by copper brazing and fusion in a reduction furnace.
4.2 Method of manufacturing the welded low carbon steel pipes
The welded low carbon steel pipes shall be made by copper coating both surfaces or inner surface of SPCC specified in JIS G 3141, shaping them into a tubular form, and sealing the edges by electric resistance welding, however inside surface, may not be copper coated if mutually agreed upon by the purchaser and the manufacturer.
4.3 Method of manufacturing the carbon steel pipes for machine structural purposes
Manufacturing of carbon steel tubes for machine structural purposes shall be pursuant to JIS G 3445 and JIS G3472.
4.4 Method of the copper and copper alloy seamless pipe and tubes
Manufacture of copper and copper alloy seamless pipes and tubes shall be pursuant to JIS H3300.
5 Dimension of pipes
5.1 Nominal diameter and dimension of pipe
Nominal diameter and and dimension of pipe shall be pursuant to Table 9.
5.2 Shape of pipe end
Formed pipe end shall be pursuant to Attached Tables 1-8.
6. Test method
Test method shall be pursuant to Table 10.
7. Inspection
7.1 Inspection of appearance
Inspection results shall meet requirements specified in the above 3.1.
7.2 Inspection of mechanical properties
Inspection shall be conducted pursuant to the above 6 and the results shall meet requirements specified in the above 4.3.
7.3 Inspection of dimensions
Inspection results shall meet requirements specified in the above 5.
7.4 Inspection of surfacetreatment
Inspection shall be conducted by the above 6 and the results shall meet requirements specified in the above 3.4.
7.5 Inspection of guarantee pressure
Inspection results shall meet requirements specified in the above 6.
8. Designation of product
Designation of products shall be pursuant to the standard number, type of tubing, and type and nominal diameter of outside surface.