Weld quality failure caused by used welded pipe machines (6)
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【概要描述】When manufacturing welded pipes for used welded pipe machines, judging that the quality of the welded pipes meets the standard depends on the quality of the welds. Therefore, the quality of the weld is very important, so sometimes it is necessary to rule out the quality of the weld. We perform analyses to understand weld quality failures.
Weld quality failure caused by used welded pipe machines (6)
【概要描述】When manufacturing welded pipes for used welded pipe machines, judging that the quality of the welded pipes meets the standard depends on the quality of the welds. Therefore, the quality of the weld is very important, so sometimes it is necessary to rule out the quality of the weld. We perform analyses to understand weld quality failures.
- Sort:Information
- Auth:
- Source:
- Release time:2023-02-01 11:30
- Pvs:
When manufacturing welded pipes for used welded pipe machines, judging that the quality of the welded pipes meets the standard depends on the quality of the welds. Therefore, the quality of the weld is very important, so sometimes it is necessary to rule out the quality of the weld. We perform analyses to understand weld quality failures.
These weld quality failures will occur when the used welded pipe machines is making pipes: ① through-length lap welding. ② Periodic lap welding. ③ Open the seam. ④ Trachoma. ⑤ Peach-shaped tube. ⑥ Weld seam gnawed. ⑦Outer burr planing. ⑧ Heating. ⑨ The current is small. ⑩ Melting of induction coils and electrodes. ⑪ Fire. ⑫ "No high pressure" phenomenon. We can summarize 12 causes of weld quality failures.
Weld seam gnawed
There are two forms of gnawing of welds, one is crescent-shaped scratches; the other is indentation. This kind of trauma is generally relatively minor and will not affect the quality of the weld, but the surface of the pipe is not very beautiful. Lap welds are formed when the depression marks become indented. Pinhole-type sand holes may appear in the crescent-shaped marks produced by the rupture of the upper edge of the extrusion roller hole. Therefore, we distinguish this type of accident from other scratch accidents.
(1) Crescent moon marks. The crescent-shaped scratch marks are one of the main scars on the weld, most of which are caused by the squeezing roller. Sometimes the vertical roller that forms a closed hole pattern will also cause scratches, mainly because the upper edge of the hole pattern appears. It is caused by slight cracks falling off the edge or other hard substances sticking to the edge of the hole. Especially after the extrusion roller is heated, many small cracks will be generated on the edge of the hole, and various oxidized metal impurities will be adhered, which is the cause of where the scratching problem lies. When the machine is stopped, we can use our fingers to do a touch inspection along the upper edge of the hole pattern, and repair or replace it according to the situation.
(2) Indentation. The indentation is mainly caused by the upper roll forming the closed hole pattern. Due to the characteristics of the hole structure, the bottom diameter of the upper roller is the most stressed. When the hardness of the roll is low, the wear of the pass is accelerated, and when the hardness of the roll is high, the bottom diameter of the pass is very prone to quenching cracks, and the cracked roll edge will cause many slight indentations to the weld. As the quench cracking problem increases and the reduction force increases, the indentation will become more serious. Therefore, it should be replaced in time when the hole type is found to be quenched and cracked.
Outer burr planing
Any scars that do not meet the product quality requirements formed after the outer burr is removed are called planing injuries. Although the chance of gouging is very small, it directly affects the appearance quality of the product. In order to reduce planing accidents, the cutting tools should be sharpened first, so as to improve the planing quality and save the tools. Secondly, it is necessary to ensure the stability and flexibility of the planing equipment, and to find a targeted treatment method in the event of an accident.
(1) Burning knife. Burning a knife is an accident that happens by accident. Generally, in production, the unit suddenly slows down and the heating temperature is extremely high, or the unit has just started to heat up before reaching the normal speed, which will make the high-temperature burr chips not easy to plan off the pipe surface and accumulate on the cutting edge. The blade burns out. This requires us to pay attention to the coordination and matching of operation actions and time in production, as well as the timely response of operations.
(2) The weld is uneven. The longitudinal plane of the weld seam after planing is wavy, which is called planing unevenness. If the waves are as tight as a washboard, it is usually caused by the fact that the relief angle of the cutting tool is too small or the strength of the tool bar is not enough to cause vibration. If the wave is a large wave with a long period, it generally occurs on a smaller pipe diameter. Due to its low weight, the pipe on the idler will bob up and down when planing, forming a wave shape. In addition, the instability of the tool holder will also produce a large wave jump and form a wavy planing result.
(3) Planing (scraping) partial. The welded seam after planing is an inclined plane, commonly known as planing (scraping) deviation (Figure 26).
There are two main reasons for the planing (scraping) deviation.
One is that the cutting tool is installed inclined, and this problem is relatively easy to solve.
The other is caused by the pipe turning. If it is only a slight planing deviation and does not affect the welding effect, we can adjust the planing knife a little, or control the direction of the welding seam by adjusting the angle and pressure of the guide roller.
(4) Plane. Sometimes we can find that a wide and flat wound is left after the burr is removed. In fact, this has nothing to do with planing, but is caused by the "peach-shaped" pipe, which causes the welding seam to form large external burrs after extrusion, so it is necessary to replace the new extrusion roller immediately. Get good weld results and weld gouging quality.
The above is one of the reasons for the quality failure of the welding seam when the used welded pipe machines is making pipes, such as the welding seam gnawing and the external burr gouging. The main reasons for the formation of weld gnawing are (1)Crescent moon marks. (2) Indentation. There are also the main reasons for the formation of external burr planing (1) burning knife. (2) The weld is uneven. (3) Planing (scraping) partial. (4) Plane.
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Time of issue : 2025-07-11
Assessing the condition of a used slitting line requires a systematic approach to determine its operational capability and remaining service life. Unlike new equipment, pre-owned machines exhibit varying degrees of wear that directly impact performance and value. Below are essential factors to consider when evaluating a used slitting line.
Structural Integrity and Frame Condition
The machine's frame serves as the foundation for precision operations. Inspect for signs of structural fatigue, including cracks, welds, or deformations in the main frame. Check for corrosion, particularly in environments where the used slitting line may have been exposed to moisture or chemicals. A laser alignment test can reveal whether critical components remain properly positioned after years of operation.
Mechanical Wear of Core Components
Examine high-wear components such as shafts, bearings, and gears for excessive play or scoring. The decoiler and recoiler mandrels should be evaluated for straightness and grip strength. On the slitting unit, inspect spindle runout and blade holder conditions. These elements directly affect the machine's ability to maintain tolerances during operation.
Electrical System and Control Reliability
Assess the condition of motors, drives, and control systems. Older used slitting lines may have obsolete electrical components that require upgrading. Test the responsiveness of the PLC or CNC interface and check for consistency in tension control systems. Modernization potential should be considered when evaluating long-term viability.
Hydraulic and Pneumatic Performance
Hydraulic systems in a used slitting line often show signs of leakage or pressure loss. Inspect cylinders, valves, and pumps for proper operation. Pneumatic components should be checked for air leaks and actuator responsiveness. Fluid analysis can reveal contamination levels in hydraulic systems.
Blade Condition and Cutting Accuracy
The slitting knives and associated tooling represent critical wear components. Measure blade sharpness and check for chips or uneven wear patterns. Evaluate the blade adjustment mechanisms for smooth operation and precision. Test cuts on sample material reveal the machine's current cutting capability.
Material Handling System Functionality
Assess the condition of levelers, straighteners, and feed systems. Look for worn rollers, misaligned guides, and tension measurement accuracy. The material handling system significantly impacts the final product quality and operational efficiency of the used slitting line.
Documentation and Service History Review
Request maintenance records and operational logs to understand the machine's service background. Regular servicing and proper lubrication history indicate better-preserved conditions. Verify hours of operation and review any major repairs or component replacements.
Performance Testing Under Load
Conduct trial runs with actual production materials to evaluate the used slitting line under working conditions. Monitor vibration levels, noise patterns, and temperature variations during operation. Measure slit material for dimensional accuracy and edge quality to assess current capabilities.
Obsolescence and Upgrade Potential
Evaluate whether the machine's technology remains relevant for current production needs. Consider the availability of replacement parts and potential upgrade paths for control systems or critical components. Some older used slitting lines offer excellent mechanical foundations for modernization.
Economic Value Assessment
Compare the machine's condition against current market prices for similar equipment. Factor in potential refurbishment costs and expected service life to determine true value. A thorough evaluation helps avoid unexpected expenses after purchase.
By systematically examining these aspects, buyers can make informed decisions about a used slitting line's suitability for their production requirements. Professional inspection services can provide additional assurance when evaluating higher-value equipment.
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
Assessing the condition of a used slitting line requires a systematic approach to determine its operational capability and remaining service life. Unlike new equipment, pre-owned machines exhibit varying degrees of wear that directly impact performance and value. Below are essential factors to consider when evaluating a used slitting line.
Structural Integrity and Frame Condition
The machine's frame serves as the foundation for precision operations. Inspect for signs of structural fatigue, including cracks, welds, or deformations in the main frame. Check for corrosion, particularly in environments where the used slitting line may have been exposed to moisture or chemicals. A laser alignment test can reveal whether critical components remain properly positioned after years of operation.
Mechanical Wear of Core Components
Examine high-wear components such as shafts, bearings, and gears for excessive play or scoring. The decoiler and recoiler mandrels should be evaluated for straightness and grip strength. On the slitting unit, inspect spindle runout and blade holder conditions. These elements directly affect the machine's ability to maintain tolerances during operation.
Electrical System and Control Reliability
Assess the condition of motors, drives, and control systems. Older used slitting lines may have obsolete electrical components that require upgrading. Test the responsiveness of the PLC or CNC interface and check for consistency in tension control systems. Modernization potential should be considered when evaluating long-term viability.
Hydraulic and Pneumatic Performance
Hydraulic systems in a used slitting line often show signs of leakage or pressure loss. Inspect cylinders, valves, and pumps for proper operation. Pneumatic components should be checked for air leaks and actuator responsiveness. Fluid analysis can reveal contamination levels in hydraulic systems.
Blade Condition and Cutting Accuracy
The slitting knives and associated tooling represent critical wear components. Measure blade sharpness and check for chips or uneven wear patterns. Evaluate the blade adjustment mechanisms for smooth operation and precision. Test cuts on sample material reveal the machine's current cutting capability.
Material Handling System Functionality
Assess the condition of levelers, straighteners, and feed systems. Look for worn rollers, misaligned guides, and tension measurement accuracy. The material handling system significantly impacts the final product quality and operational efficiency of the used slitting line.
Documentation and Service History Review
Request maintenance records and operational logs to understand the machine's service background. Regular servicing and proper lubrication history indicate better-preserved conditions. Verify hours of operation and review any major repairs or component replacements.
Performance Testing Under Load
Conduct trial runs with actual production materials to evaluate the used slitting line under working conditions. Monitor vibration levels, noise patterns, and temperature variations during operation. Measure slit material for dimensional accuracy and edge quality to assess current capabilities.
Obsolescence and Upgrade Potential
Evaluate whether the machine's technology remains relevant for current production needs. Consider the availability of replacement parts and potential upgrade paths for control systems or critical components. Some older used slitting lines offer excellent mechanical foundations for modernization.
Economic Value Assessment
Compare the machine's condition against current market prices for similar equipment. Factor in potential refurbishment costs and expected service life to determine true value. A thorough evaluation helps avoid unexpected expenses after purchase.
By systematically examining these aspects, buyers can make informed decisions about a used slitting line's suitability for their production requirements. Professional inspection services can provide additional assurance when evaluating higher-value equipment.
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 : 2025-07-10
The proper selection and preparation of a production site are critical factors in ensuring optimal performance and safety when operating a used slitting line. Unlike new equipment, second-hand machinery may have specific spatial and environmental needs due to previous usage patterns or wear conditions. Below are key considerations for selecting an appropriate workspace for a used slitting line.
Space Allocation and Layout Planning
Adequate floor space must be allocated to accommodate the entire slitting line, including material storage areas. The layout should allow for smooth coil loading and unloading operations, with sufficient clearance for overhead cranes or forklifts. Since a used slitting line may require more frequent maintenance access, additional space around critical components like the slitter head and tension stations should be incorporated.
Floor Load Capacity and Foundation Requirements
The chosen location must have a reinforced concrete floor capable of supporting the substantial weight of both the machinery and coiled materials. Older slitting lines often have heavier frames compared to modern equivalents, making floor strength assessment crucial. Vibration dampening considerations should be addressed, especially if the equipment shows signs of increased vibration due to wear.
Material Flow Optimization
The workspace should facilitate logical material movement from raw coil storage through processing to finished product staging. For a used slitting line, particular attention should be paid to entry and exit points to prevent material handling bottlenecks. The layout must account for any peculiarities in the machine's feeding or discharge mechanisms that may have developed during its previous service life.
Environmental Conditions Control
Maintaining stable environmental conditions helps preserve the accuracy of a used slitting line. The area should be protected from extreme temperature fluctuations and humidity variations that could affect material properties or machine tolerances. Proper ventilation is essential, especially when processing materials that generate dust or fumes.
Power Supply and Utility Requirements
A used slitting line may have specific electrical needs based on its original configuration and any subsequent modifications. The workspace must provide appropriate power capacity, including voltage stability and phase requirements. Compressed air lines, hydraulic power units, and coolant systems should be positioned for optimal machine performance.
Safety Zones and Emergency Access
Clear safety perimeters must be established around the slitting line, accounting for the machine's age and potential reliability issues. Emergency stop buttons and fire suppression equipment should be easily accessible. The layout should enable quick evacuation routes and provide space for safety barriers where needed.
Lighting and Visibility Considerations
Adequate lighting is particularly important for older equipment where visual inspection of material quality and machine operation is crucial. Task lighting should be positioned to illuminate critical areas such as the slitting zone and tension monitoring points without creating glare or shadows.
Future Expansion and Flexibility
When siting a used slitting line, consideration should be given to potential future upgrades or reconfigurations. The workspace should allow for possible additions of auxiliary equipment or modifications to the material handling system.
Noise Control Measures
Older slitting lines may generate higher noise levels, requiring appropriate acoustic treatment of the workspace. This could include sound-absorbing wall panels or strategic placement of noise barriers between the equipment and operator stations.
By carefully evaluating these factors when selecting a production site, operators can maximize the efficiency and service life of a used slitting line while maintaining a safe working environment. The workspace should be periodically reassessed as the machine's performance characteristics evolve over time.
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
The proper selection and preparation of a production site are critical factors in ensuring optimal performance and safety when operating a used slitting line. Unlike new equipment, second-hand machinery may have specific spatial and environmental needs due to previous usage patterns or wear conditions. Below are key considerations for selecting an appropriate workspace for a used slitting line.
Space Allocation and Layout Planning
Adequate floor space must be allocated to accommodate the entire slitting line, including material storage areas. The layout should allow for smooth coil loading and unloading operations, with sufficient clearance for overhead cranes or forklifts. Since a used slitting line may require more frequent maintenance access, additional space around critical components like the slitter head and tension stations should be incorporated.
Floor Load Capacity and Foundation Requirements
The chosen location must have a reinforced concrete floor capable of supporting the substantial weight of both the machinery and coiled materials. Older slitting lines often have heavier frames compared to modern equivalents, making floor strength assessment crucial. Vibration dampening considerations should be addressed, especially if the equipment shows signs of increased vibration due to wear.
Material Flow Optimization
The workspace should facilitate logical material movement from raw coil storage through processing to finished product staging. For a used slitting line, particular attention should be paid to entry and exit points to prevent material handling bottlenecks. The layout must account for any peculiarities in the machine's feeding or discharge mechanisms that may have developed during its previous service life.
Environmental Conditions Control
Maintaining stable environmental conditions helps preserve the accuracy of a used slitting line. The area should be protected from extreme temperature fluctuations and humidity variations that could affect material properties or machine tolerances. Proper ventilation is essential, especially when processing materials that generate dust or fumes.
Power Supply and Utility Requirements
A used slitting line may have specific electrical needs based on its original configuration and any subsequent modifications. The workspace must provide appropriate power capacity, including voltage stability and phase requirements. Compressed air lines, hydraulic power units, and coolant systems should be positioned for optimal machine performance.
Safety Zones and Emergency Access
Clear safety perimeters must be established around the slitting line, accounting for the machine's age and potential reliability issues. Emergency stop buttons and fire suppression equipment should be easily accessible. The layout should enable quick evacuation routes and provide space for safety barriers where needed.
Lighting and Visibility Considerations
Adequate lighting is particularly important for older equipment where visual inspection of material quality and machine operation is crucial. Task lighting should be positioned to illuminate critical areas such as the slitting zone and tension monitoring points without creating glare or shadows.
Future Expansion and Flexibility
When siting a used slitting line, consideration should be given to potential future upgrades or reconfigurations. The workspace should allow for possible additions of auxiliary equipment or modifications to the material handling system.
Noise Control Measures
Older slitting lines may generate higher noise levels, requiring appropriate acoustic treatment of the workspace. This could include sound-absorbing wall panels or strategic placement of noise barriers between the equipment and operator stations.
By carefully evaluating these factors when selecting a production site, operators can maximize the efficiency and service life of a used slitting line while maintaining a safe working environment. The workspace should be periodically reassessed as the machine's performance characteristics evolve over time.
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 : 2025-07-09
Proper training is essential for ensuring safe and efficient operation of a used slitting line. Since second-hand equipment may have unique wear patterns or modifications, operators must be thoroughly trained to handle its specific requirements. Below are key aspects of personnel training for a used slitting line:
Understanding Machine Components and Functions
Operators must familiarize themselves with all parts of the slitting line, including the decoiler, slitter, tension control system, and recoiler. Training should cover the purpose of each component, common wear points, and how to identify signs of malfunction. Since a used slitting line may have undergone previous repairs or adjustments, operators should learn its specific configuration.
Safety Procedures and Emergency Protocols
Safety training is critical when working with a used slitting line. Operators must understand lockout/tagout (LOTO) procedures to prevent accidental startups during maintenance. They should also be trained on emergency stop functions, proper PPE usage, and how to handle material jams safely. Since older machines may lack modern safety features, extra caution is necessary.
Material Handling and Setup
Proper material loading and alignment are crucial for smooth operation. Training should include how to safely mount and center coils on the decoiler, adjust tension controls, and thread material through the slitting line. Operators should learn how to select and install the correct blades for different materials, as improper setup can lead to poor cuts or machine damage.
Blade Maintenance and Adjustment
Since blade wear is a common issue in used slitting lines, operators must be trained in blade inspection, sharpening, and replacement. They should understand how to adjust blade gaps for different material thicknesses and recognize when blades need servicing. Proper handling techniques should be emphasized to prevent injuries.
Troubleshooting Common Issues
Operators should be trained to identify and resolve frequent problems in a used slitting line, such as misaligned material, uneven tension, or blade chatter. Training should include basic diagnostic steps and when to escalate issues to maintenance personnel. Documenting recurring problems can help improve long-term reliability.
Preventive Maintenance Practices
Regular maintenance is key to extending the lifespan of a used slitting line. Operators should learn daily inspection routines, lubrication points, and how to clean critical components. Training should emphasize the importance of reporting unusual noises, vibrations, or performance changes before they lead to major failures.
Quality Control and Inspection
Operators must understand how to check slit material for defects such as burrs, edge waves, or dimensional inaccuracies. Training should include using measuring tools and maintaining consistent quality standards. Since a used slitting line may have slight deviations, operators should know how to compensate for them.
Handover and Shift Communication
In multi-shift operations, clear communication is vital. Operators should be trained in proper handover procedures, including reporting machine status, ongoing issues, and maintenance needs. This ensures smooth transitions and reduces downtime.
By implementing comprehensive training programs, companies can maximize the efficiency and safety of a used slitting line, reducing operational risks and improving productivity. Regular refresher courses should be conducted to keep skills updated.
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
Proper training is essential for ensuring safe and efficient operation of a used slitting line. Since second-hand equipment may have unique wear patterns or modifications, operators must be thoroughly trained to handle its specific requirements. Below are key aspects of personnel training for a used slitting line:
Understanding Machine Components and Functions
Operators must familiarize themselves with all parts of the slitting line, including the decoiler, slitter, tension control system, and recoiler. Training should cover the purpose of each component, common wear points, and how to identify signs of malfunction. Since a used slitting line may have undergone previous repairs or adjustments, operators should learn its specific configuration.
Safety Procedures and Emergency Protocols
Safety training is critical when working with a used slitting line. Operators must understand lockout/tagout (LOTO) procedures to prevent accidental startups during maintenance. They should also be trained on emergency stop functions, proper PPE usage, and how to handle material jams safely. Since older machines may lack modern safety features, extra caution is necessary.
Material Handling and Setup
Proper material loading and alignment are crucial for smooth operation. Training should include how to safely mount and center coils on the decoiler, adjust tension controls, and thread material through the slitting line. Operators should learn how to select and install the correct blades for different materials, as improper setup can lead to poor cuts or machine damage.
Blade Maintenance and Adjustment
Since blade wear is a common issue in used slitting lines, operators must be trained in blade inspection, sharpening, and replacement. They should understand how to adjust blade gaps for different material thicknesses and recognize when blades need servicing. Proper handling techniques should be emphasized to prevent injuries.
Troubleshooting Common Issues
Operators should be trained to identify and resolve frequent problems in a used slitting line, such as misaligned material, uneven tension, or blade chatter. Training should include basic diagnostic steps and when to escalate issues to maintenance personnel. Documenting recurring problems can help improve long-term reliability.
Preventive Maintenance Practices
Regular maintenance is key to extending the lifespan of a used slitting line. Operators should learn daily inspection routines, lubrication points, and how to clean critical components. Training should emphasize the importance of reporting unusual noises, vibrations, or performance changes before they lead to major failures.
Quality Control and Inspection
Operators must understand how to check slit material for defects such as burrs, edge waves, or dimensional inaccuracies. Training should include using measuring tools and maintaining consistent quality standards. Since a used slitting line may have slight deviations, operators should know how to compensate for them.
Handover and Shift Communication
In multi-shift operations, clear communication is vital. Operators should be trained in proper handover procedures, including reporting machine status, ongoing issues, and maintenance needs. This ensures smooth transitions and reduces downtime.
By implementing comprehensive training programs, companies can maximize the efficiency and safety of a used slitting line, reducing operational risks and improving productivity. Regular refresher courses should be conducted to keep skills updated.
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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