Common used welded pipe machine sizing section welded pipe quality defects
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【概要描述】The common quality defects of welded pipe in the sizing section of used welded pipe machine can be divided into three categories: dimensional tolerance defects, surface defects and straightness defects. According to these three types of common sizing section welded pipe quality defects are described in detail.
Common used welded pipe machine sizing section welded pipe quality defects
【概要描述】The common quality defects of welded pipe in the sizing section of used welded pipe machine can be divided into three categories: dimensional tolerance defects, surface defects and straightness defects. According to these three types of common sizing section welded pipe quality defects are described in detail.
- Sort:Information
- Auth:
- Source:
- Release time:2023-04-15 11:30
- Pvs:
The common quality defects of welded pipe in the sizing section of used welded pipe machine can be divided into three categories: dimensional tolerance defects, surface defects and straightness defects. According to these three types of common sizing section welded pipe quality defects are described in detail.
Dimensional tolerance defects
The adjustment of the size of the welded pipe simply exceeds the upper or lower difference is far less difficult than the size fluctuation. The large fluctuation of the outer dimension of the welded pipe refers to the large change of the outer dimension in the longitudinal measurement direction of the welded pipe, which is close to or beyond the tolerance range of the welded pipe, commonly known as "section difference". There are two kinds of phenomena: periodicity and randomness. Take the round tube as an example. See the table below for their causes and adjustment measures.
Surface defects
The surface defects of sizing welded pipes mainly include pits, bumps, indentations, scratches, oxide layer intrusion, etc. The causes and solutions are similar to those of molding. These defects are allowed to be removed for general-purpose pipes, but the removal depth must not be lower than the negative deviation of the nominal wall thickness, otherwise they should be discarded. As for the surface quality requirements of used welded pipe machine manufacturing medium and high-grade furniture pipes, automobile pipes, API pipes, etc., the requirements stipulated in the agreement between the two parties should be met.
Here, we will talk about the common rolling angle defects in (square-moment) special-shaped pipes. The rolling angle defects are divided into single-sided rolling angles and double-sided rolling angles. The method of judging is to use your finger to cross the pipe surface horizontally to the corner arc. If there is a slap in the hand, it indicates that there is a rolled corner defect. In most cases, only one or two corners are rolled.
There are roughly five main reasons for the formation of the rolling angle: (1) The rolls are dislocated and the tube surface is crushed; (2) The roll gap is too large, and the pass line is not long enough; (3) The shaping allowance is too large, and the tube corner is blocked by the roll gap. Corner crushing; (4) The single pass rolling pressure is too large, and the edge of the pass will crush the tube surface; (5) The roll deviates from the rolling center line, resulting in excessive rolling force on a corner, and the corner is crushed. For rolling angle defects, firstly check in reverse according to the mapping principle, and then take corresponding corrective measures.
Straightness defect
The straightness defect here refers to the straightness of the line, including bending, twisting and twisting. During the production of welded pipes, the straightness often changes. The essence of straightness is various stress balance problems in the pipe body, and the sudden change factors affecting the stress balance are mainly material changes, including width, thickness, hardness, etc. It is only explained by the hardness change. After the stress of the straightening system is balanced, it indicates that the system recognizes the existing hardness, and the welded pipe produced by the system is "naturally" straight; however, once the hardness changes, the system does not recognize the new hardness, the stress When the balance is broken, the welded pipe bends; without manual intervention, the pipe bends forever until it is readjusted and a new stress balance system is established. This reminds the operator from one side that in the normal production process, if the straightness of the welded pipe suddenly changes, it is necessary to think that something must have happened in the production process.
Similarly, when the equipment accuracy, cooling system, ambient temperature, operation adjustment and other. change, the existing balance between the invisible welded pipe unit and the welded pipe will be hidden, resulting in the bending of the welded pipe. As far as changes in ambient temperature are concerned, I believe that most of the adjustment workers have this experience: the unit that produced well the day before, the original crew came back to start up after a night of shutdown, and found that all the welded pipes produced were bent. This is actually the invisible factor of temperature, which involves a thermal balance problem. The thermal balance of the welded pipe unit means that after the unit runs for a certain period of time, the temperature of the equipment parts, bearings, hole type, coolant, etc. all rise to a certain height, so various stresses reach a tacit agreement with the welded pipe at that time and are in a balanced state; After the overnight shutdown, the temperature of the unit parts, bearings, rolls and coolants are all in a cold state, which is difficult to achieve stress balance with the hot welded pipe at once, so the welded pipe is bent.
For used welded pipe machine, some of the defects of welded pipes and the reasons for the formation of defects are obvious, and some are more concealed; Therefore, for the disposal of some welded pipe defects, it is not possible to simply discuss the matter, but to have a global concept, and use a systematic concept to guide the adjustment of welded pipes and the search for the cause of defects.
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Time of issue : 2025-02-11
1. The characteristics of high-precision steel pipe
High dimensional accuracy: small outer diameter, wall thickness tolerance (usually up to ±0.05mm), low ellipticity.
Excellent surface quality: smooth weld without burrs, surface finish Ra≤0.8μm.
Stable mechanical properties: weld strength close to the base material, uniform compressive/tensile properties.
Applicable materials: stainless steel (304/316L), carbon steel, alloy steel (such as API series), etc.
2. Core production process
(1) Type of pipe welding machine
High-frequency welding (HFW) : high efficiency, suitable for medium thin wall pipe (Φ10~Φ600mm), need to cooperate with precision forming unit.
Laser welding: small heat affected zone, narrow weld (0.1~0.3mm), suitable for ultra-thin walls (such as 0.3mm) or special alloys.
TIG welding: For high alloy steel or thick wall pipe, higher weld purity.
(2) Key process links
Forming process: multi-roll continuous cold forming, dynamic adjustment of roll parameters to compensate for rebound.
Welding control:
High frequency welding: precise control of current frequency (100~400kHz) and extrusion amount.
Laser welding: focus position accuracy ±0.05mm, real-time depth monitoring (such as CCD vision).
Online detection:
Eddy current inspection (ET) : Detection of surface cracks.
Ultrasonic inspection (UT) : detection of internal defects (sensitivity Φ0.5mm equivalent flat hole).
Laser caliper: Outer diameter closed loop control (accuracy ±0.01mm).
3. Post-processing technology
Heat treatment: bright annealing (hydrogen nitrogen protection atmosphere) to eliminate stress, hardness fluctuation ≤3HRC.
Straightening: multi-roll precision straightening, straightness ≤0.5mm/m.
Surface treatment:
Electrolytic polishing (EP) : For medical/food grade stainless steel tubes, Ra up to 0.2μm.
Coating: hot dip galvanizing (zinc layer ≥80μm) or electroless nickel plating (uniform thickness ±2μm).
4. Typical application areas
Automobile manufacturing: fuel injection pipe (tolerance ±0.03mm), hydraulic pipe.
Semiconductor equipment: Ultra-high clean gas delivery pipe (inner wall EP treatment, particle ≤Class 5).
Medical instruments: endoscopic catheter (Φ1~5mm, wall thickness 0.1mm).
Energy industry: Instrument tubes for nuclear power plants (SA213-TP347H material, intergranular corrosion test passed).
5. Quality control standards
International standard:
ASTM A269 (Universal Seamless and Welded Austenitic Stainless Steel Pipe)
EN 10305-4 (Precision welded pipes for hydraulic systems)
Industry certification: ISO 9001, PED 2014/68/EU (Pressure Equipment Directive).
6. Technological trends
Intelligent production: AI algorithm optimizes welding parameters, and the yield is increased to more than 99.5%.
Composite process: laser + arc composite welding, both efficiency and quality (speed increased by 30%).
Green manufacturing: low energy high frequency power supply (efficiency ≥90%), waste acid recovery ≥95%.
Through the above process optimization and strict quality control, the high-precision steel pipe produced by the pipe welding machine can meet the demanding requirements of size, performance and reliability in high-end industrial fields. In actual production, the process route needs to be customized according to the material characteristics and uses, for example, medical tubes need to undergo additional passivation treatment and biocompatibility testing.
For more information, please pay attention to the website of Jinyujie Mechanical and Electrical Used Pipe Mill Supplier:www.usedpipemill.com
JinYuJie-Used Pipe Mills Supplier(Please click the link→) :second-hand pipe mill
1. The characteristics of high-precision steel pipe
High dimensional accuracy: small outer diameter, wall thickness tolerance (usually up to ±0.05mm), low ellipticity.
Excellent surface quality: smooth weld without burrs, surface finish Ra≤0.8μm.
Stable mechanical properties: weld strength close to the base material, uniform compressive/tensile properties.
Applicable materials: stainless steel (304/316L), carbon steel, alloy steel (such as API series), etc.
2. Core production process
(1) Type of pipe welding machine
High-frequency welding (HFW) : high efficiency, suitable for medium thin wall pipe (Φ10~Φ600mm), need to cooperate with precision forming unit.
Laser welding: small heat affected zone, narrow weld (0.1~0.3mm), suitable for ultra-thin walls (such as 0.3mm) or special alloys.
TIG welding: For high alloy steel or thick wall pipe, higher weld purity.
(2) Key process links
Forming process: multi-roll continuous cold forming, dynamic adjustment of roll parameters to compensate for rebound.
Welding control:
High frequency welding: precise control of current frequency (100~400kHz) and extrusion amount.
Laser welding: focus position accuracy ±0.05mm, real-time depth monitoring (such as CCD vision).
Online detection:
Eddy current inspection (ET) : Detection of surface cracks.
Ultrasonic inspection (UT) : detection of internal defects (sensitivity Φ0.5mm equivalent flat hole).
Laser caliper: Outer diameter closed loop control (accuracy ±0.01mm).
3. Post-processing technology
Heat treatment: bright annealing (hydrogen nitrogen protection atmosphere) to eliminate stress, hardness fluctuation ≤3HRC.
Straightening: multi-roll precision straightening, straightness ≤0.5mm/m.
Surface treatment:
Electrolytic polishing (EP) : For medical/food grade stainless steel tubes, Ra up to 0.2μm.
Coating: hot dip galvanizing (zinc layer ≥80μm) or electroless nickel plating (uniform thickness ±2μm).
4. Typical application areas
Automobile manufacturing: fuel injection pipe (tolerance ±0.03mm), hydraulic pipe.
Semiconductor equipment: Ultra-high clean gas delivery pipe (inner wall EP treatment, particle ≤Class 5).
Medical instruments: endoscopic catheter (Φ1~5mm, wall thickness 0.1mm).
Energy industry: Instrument tubes for nuclear power plants (SA213-TP347H material, intergranular corrosion test passed).
5. Quality control standards
International standard:
ASTM A269 (Universal Seamless and Welded Austenitic Stainless Steel Pipe)
EN 10305-4 (Precision welded pipes for hydraulic systems)
Industry certification: ISO 9001, PED 2014/68/EU (Pressure Equipment Directive).
6. Technological trends
Intelligent production: AI algorithm optimizes welding parameters, and the yield is increased to more than 99.5%.
Composite process: laser + arc composite welding, both efficiency and quality (speed increased by 30%).
Green manufacturing: low energy high frequency power supply (efficiency ≥90%), waste acid recovery ≥95%.
Through the above process optimization and strict quality control, the high-precision steel pipe produced by the pipe welding machine can meet the demanding requirements of size, performance and reliability in high-end industrial fields. In actual production, the process route needs to be customized according to the material characteristics and uses, for example, medical tubes need to undergo additional passivation treatment and biocompatibility testing.
For more information, please pay attention to the website of Jinyujie Mechanical and Electrical Used Pipe Mill Supplier:www.usedpipemill.com
JinYuJie-Used Pipe Mills Supplier(Please click the link→) :second-hand pipe mill

Time of issue : 2025-02-08
1.The role of pipe welding machine in the manufacture of automobile frame
Pipe production: The welding pipe machine is used to manufacture high-precision welded steel pipes, which constitute the longitudinal beams, beams, anti-collision beams and other key components of the automobile frame. High frequency welding (HFW) or laser welding technology can produce steel pipes with uniform wall thickness and strength of more than 800MPa to meet the needs of lightweight.
Customized processing: Through flexible forming technology, the welding machine can produce special-shaped cross section pipes (such as rectangular, trapezoidal), adapt to the topology optimization design of different models of frames, improve space utilization and impact energy absorption efficiency.
2.The core requirements of the welding pipe process for automobile frames
Material properties: DP600/DP800 duplex steel or 22MnB5 thermoforming steel should be used, and online heat treatment (such as induction annealing) should be carried out after welding to ensure the microstructure consistency between the weld zone and the base material and avoid HAZ (heat affected zone) softening.
Dimensional accuracy: Diameter tolerance should be controlled within ±0.2mm, ellipticity ≤0.5%, to ensure the matching accuracy of the assembly and stamping parts (clearance <0.5mm).
3.Key technology breakthrough point
Laser-MAG composite welding: the penetration depth can reach 8mm, the welding speed is increased to 6m/min, the heat input is reduced by 30%, and the welding deformation of the frame is significantly reduced (≤1.5mm/m).
Online quality monitoring: high-speed CCD vision system (sampling rate 2000fps) with eddy current detection, to achieve real-time detection of weld defects, miss rate <0.01%.
4.Cost-performance balance
Compared with the stamping and welding structure, the welded pipe frame can reduce the weight by 15-20%, the material utilization rate is increased to 95%, and the manufacturing cost of the bicycle is reduced by about 1200 yuan. However, it is necessary to increase the investment in roller forming molds (about 2 million yuan/set).
5.Industry Application Cases
- An independent brand pure level station adopts 3D variable cross-section welded pipe subframe, with torsional rigidity increased to 27000Nm/°, 40% higher than the traditional structure, and the battery pack space utilization increased by 12%.
Conclusion
The penetration rate of welded pipe technology in the field of automotive frames is growing at a rate of 8% per year, and future development directions include:
Intelligent welded pipe system (digital twin model real-time control molding parameters)
Magnesium alloy /CFRP composite pipe welding process
Topological optimization driven continuous forming technology for variable thickness pipes
It is recommended to pay attention to the update of the ISO 15614 standard and the latest certification requirements for automotive welded pipe processes in ASME BPVC Section IX to ensure technical compliance.
For more information, please pay attention to the website of Jinyujie Mechanical and Electrical Used Pipe Mill Supplier:www.usedpipemill.com
JinYuJie-Used Pipe Mills Supplier(Please click the link→) :second-hand pipe mill
1.The role of pipe welding machine in the manufacture of automobile frame
Pipe production: The welding pipe machine is used to manufacture high-precision welded steel pipes, which constitute the longitudinal beams, beams, anti-collision beams and other key components of the automobile frame. High frequency welding (HFW) or laser welding technology can produce steel pipes with uniform wall thickness and strength of more than 800MPa to meet the needs of lightweight.
Customized processing: Through flexible forming technology, the welding machine can produce special-shaped cross section pipes (such as rectangular, trapezoidal), adapt to the topology optimization design of different models of frames, improve space utilization and impact energy absorption efficiency.
2.The core requirements of the welding pipe process for automobile frames
Material properties: DP600/DP800 duplex steel or 22MnB5 thermoforming steel should be used, and online heat treatment (such as induction annealing) should be carried out after welding to ensure the microstructure consistency between the weld zone and the base material and avoid HAZ (heat affected zone) softening.
Dimensional accuracy: Diameter tolerance should be controlled within ±0.2mm, ellipticity ≤0.5%, to ensure the matching accuracy of the assembly and stamping parts (clearance <0.5mm).
3.Key technology breakthrough point
Laser-MAG composite welding: the penetration depth can reach 8mm, the welding speed is increased to 6m/min, the heat input is reduced by 30%, and the welding deformation of the frame is significantly reduced (≤1.5mm/m).
Online quality monitoring: high-speed CCD vision system (sampling rate 2000fps) with eddy current detection, to achieve real-time detection of weld defects, miss rate <0.01%.
4.Cost-performance balance
Compared with the stamping and welding structure, the welded pipe frame can reduce the weight by 15-20%, the material utilization rate is increased to 95%, and the manufacturing cost of the bicycle is reduced by about 1200 yuan. However, it is necessary to increase the investment in roller forming molds (about 2 million yuan/set).
5.Industry Application Cases
- An independent brand pure level station adopts 3D variable cross-section welded pipe subframe, with torsional rigidity increased to 27000Nm/°, 40% higher than the traditional structure, and the battery pack space utilization increased by 12%.
Conclusion
The penetration rate of welded pipe technology in the field of automotive frames is growing at a rate of 8% per year, and future development directions include:
Intelligent welded pipe system (digital twin model real-time control molding parameters)
Magnesium alloy /CFRP composite pipe welding process
Topological optimization driven continuous forming technology for variable thickness pipes
It is recommended to pay attention to the update of the ISO 15614 standard and the latest certification requirements for automotive welded pipe processes in ASME BPVC Section IX to ensure technical compliance.
For more information, please pay attention to the website of Jinyujie Mechanical and Electrical Used Pipe Mill Supplier:www.usedpipemill.com
JinYuJie-Used Pipe Mills Supplier(Please click the link→) :second-hand pipe mill

Time of issue : 2025-02-07
89 The working principle of the pipe welding machine 89 The pipe welding machine uncoils the steel strip, feeds and welds it into a round steel pipe, and then cools, straightens and cuts the steel pipe to the required length. The main steps include:
1. Uncoiling: Unroll the steel strip from the drum and level it through the straightener.
2. Forming: The steel strip is rolled into a tube shape through a series of roller wheels.
3. Welding: high frequency current is used to heat the joint of the steel strip, so as to weld the steel pipe.
4. Cooling: The welded steel pipe is cooled by cooling equipment.
5. Straightening and cutting: Finally, straighten and cut the steel pipe to the required length.
The main steel pipe used in the highway fence needs to have a certain strength and impact resistance, but also corrosion resistance. Specific features include:
1. High strength: the steel pipe must be able to withstand the impact to ensure the safety of the highway.
2. Corrosion resistance: steel pipes are usually galvanized to enhance their corrosion resistance and adapt to harsh outdoor environments.
3. Standard size: The steel pipe produced generally has strict size requirements to ensure the stability of the fixed connection of each fence.
The steel pipe produced by the 89 pipe welding machine plays a skeleton role in the highway fence, and its application is reflected in:
1. Guardrail: installed on both sides of the highway or in the middle, to prevent the vehicle from losing control of the road, to protect the safety of the driver.
2. Isolation belt: Set isolation belts between lanes in different directions to prevent vehicles from crossing lanes and reduce the incidence of accidents.
3. Sound barrier: The use of steel pipe frame to support the sound barrier plate to reduce the impact of road noise on the surrounding environment.
In short, the 89 pipe welding machine plays a key role in the production of steel pipes for highway fences, ensuring the stability, durability and safety of the fences, thus providing a reliable guarantee for the safe operation of the highways.
For more information, please pay attention to the website of Jinyujie Mechanical and Electrical Used Pipe Mill Supplier:www.usedpipemill.com
JinYuJie-Used Pipe Mills Supplier(Please click the link→) :second-hand pipe mill
89 The working principle of the pipe welding machine 89 The pipe welding machine uncoils the steel strip, feeds and welds it into a round steel pipe, and then cools, straightens and cuts the steel pipe to the required length. The main steps include:
1. Uncoiling: Unroll the steel strip from the drum and level it through the straightener.
2. Forming: The steel strip is rolled into a tube shape through a series of roller wheels.
3. Welding: high frequency current is used to heat the joint of the steel strip, so as to weld the steel pipe.
4. Cooling: The welded steel pipe is cooled by cooling equipment.
5. Straightening and cutting: Finally, straighten and cut the steel pipe to the required length.
The main steel pipe used in the highway fence needs to have a certain strength and impact resistance, but also corrosion resistance. Specific features include:
1. High strength: the steel pipe must be able to withstand the impact to ensure the safety of the highway.
2. Corrosion resistance: steel pipes are usually galvanized to enhance their corrosion resistance and adapt to harsh outdoor environments.
3. Standard size: The steel pipe produced generally has strict size requirements to ensure the stability of the fixed connection of each fence.
The steel pipe produced by the 89 pipe welding machine plays a skeleton role in the highway fence, and its application is reflected in:
1. Guardrail: installed on both sides of the highway or in the middle, to prevent the vehicle from losing control of the road, to protect the safety of the driver.
2. Isolation belt: Set isolation belts between lanes in different directions to prevent vehicles from crossing lanes and reduce the incidence of accidents.
3. Sound barrier: The use of steel pipe frame to support the sound barrier plate to reduce the impact of road noise on the surrounding environment.
In short, the 89 pipe welding machine plays a key role in the production of steel pipes for highway fences, ensuring the stability, durability and safety of the fences, thus providing a reliable guarantee for the safe operation of the highways.
For more information, please pay attention to the website of Jinyujie Mechanical and Electrical Used Pipe Mill Supplier:www.usedpipemill.com
JinYuJie-Used Pipe Mills Supplier(Please click the link→) :second-hand pipe mill

Time of issue : 2025-01-23
1.Supply channels:
Online marketplaces: For example, Taobao, Alibaba, Jingdong and other platforms can search and find used equipment.
Professional used equipment market: Some areas have a special used equipment market, you can view the equipment situation on the spot.
Industry exhibitions: Participate in machinery, manufacturing related exhibitions, sometimes you can find suppliers to provide second-hand equipment opportunities.
Peers and recommendations: Ask peers and friends in the industry to obtain reliable equipment and supplier information.
2.Selection criteria:
Equipment condition: Carefully check the service life, maintenance records and running status of the equipment to ensure that the function is intact.
Brand and model: Choose well-known brands and reliable models, usually the quality is guaranteed, and the after-sales service is relatively perfect.
Price comparison: multiple inquiries to ensure reasonable prices to avoid buying inferior equipment at low prices.
Service and Accessories: Find out if the supplier provides after-sales service and accessories to ensure convenient maintenance in subsequent use.
3.Site inspection:
Equipment operation demonstration: The seller is required to perform equipment operation demonstration to observe the actual operation.
Technical Support: Evaluate the seller's technical support capabilities, including whether to provide installation and commissioning services.
Contract protection: Sign a detailed procurement contract to clarify the responsibilities of both parties, equipment specifications, payment methods, after-sales service and other content.
4.Trial Period:
Trial commitment: Try to strive for a certain trial period in order to find potential problems with the equipment during use.
Troubleshooting: During the trial period, pay close attention to the operation of the equipment, if there is a failure, contact the seller as soon as possible.
Through the above methods, you can better purchase a satisfactory second-hand pipe making machine.
For more information, please pay attention to the website of Jinyujie Mechanical and Electrical Used Pipe Mill Supplier:www.usedpipemill.com
JinYuJie-Used Pipe Mills Supplier(Please click the link→) :second-hand pipe mill
1.Supply channels:
Online marketplaces: For example, Taobao, Alibaba, Jingdong and other platforms can search and find used equipment.
Professional used equipment market: Some areas have a special used equipment market, you can view the equipment situation on the spot.
Industry exhibitions: Participate in machinery, manufacturing related exhibitions, sometimes you can find suppliers to provide second-hand equipment opportunities.
Peers and recommendations: Ask peers and friends in the industry to obtain reliable equipment and supplier information.
2.Selection criteria:
Equipment condition: Carefully check the service life, maintenance records and running status of the equipment to ensure that the function is intact.
Brand and model: Choose well-known brands and reliable models, usually the quality is guaranteed, and the after-sales service is relatively perfect.
Price comparison: multiple inquiries to ensure reasonable prices to avoid buying inferior equipment at low prices.
Service and Accessories: Find out if the supplier provides after-sales service and accessories to ensure convenient maintenance in subsequent use.
3.Site inspection:
Equipment operation demonstration: The seller is required to perform equipment operation demonstration to observe the actual operation.
Technical Support: Evaluate the seller's technical support capabilities, including whether to provide installation and commissioning services.
Contract protection: Sign a detailed procurement contract to clarify the responsibilities of both parties, equipment specifications, payment methods, after-sales service and other content.
4.Trial Period:
Trial commitment: Try to strive for a certain trial period in order to find potential problems with the equipment during use.
Troubleshooting: During the trial period, pay close attention to the operation of the equipment, if there is a failure, contact the seller as soon as possible.
Through the above methods, you can better purchase a satisfactory second-hand pipe making machine.
For more information, please pay attention to the website of Jinyujie Mechanical and Electrical Used Pipe Mill Supplier:www.usedpipemill.com
JinYuJie-Used Pipe Mills Supplier(Please click the link→) :second-hand pipe mill
Wechat: 13392281699
Email: zty@usedpipemill.com
Company address:No. A99, East Lecong Avenue, Lecong Town, Foshan City, Guangdong Province
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