Common quality problems of mechanical steel pipes during use

As an indispensable and important material in modern industry, mechanical steel pipes & tubes are widely used in mechanical equipment manufacturing, automobiles, aviation, ships and other fields. However, quality problems of mechanical steel pipes also occur from time to time, causing a lot of trouble for users. This article will introduce in detail the common quality problems and prevention and maintenance methods of mechanical steel pipes during use.

Common quality problems of mechanical steel pipes during use mainly include the following:

1. Welding quality problems

During the welding process, problems such as incomplete penetration of welds, pores and impurities in welds may occur. These defects will reduce the pressure bearing capacity and sealing of the steel pipe, resulting in a decrease in the safety performance of the steel pipe, and even cause safety accidents.

2. Corrosion problems

Mechanical steel pipes are susceptible to corrosion during use, resulting in reduced strength and durability. Common forms of corrosion include surface corrosion and internal corrosion.

3. Strength problems
Mechanical steel pipes need to withstand certain loads and pressures during use, and exceeding their load range can easily lead to breakage or deformation. Understanding the load and strength parameters of steel pipes, making scientific selections, and conducting acceptance and inspections before use are preventive measures.

4. Insufficient dimensional accuracy
The outer diameter, wall thickness and other dimensions of the steel pipe may have deviations, insufficient dimensional accuracy, high surface roughness, etc., resulting in loose connections or failure to meet use requirements.

‌5. Inner surface defects‌
Includes inner fold, inner scar, warping, inner straight, inner edge and inner bulge. These defects are caused by various reasons, such as tube quality, uneven heating, improper adjustment of perforator parameters, etc. These defects will affect the performance and safety of mechanical steel pipes. Regular maintenance of equipment, optimization of process parameters and strengthening of quality inspection can effectively reduce these defects.

‌6. Outer surface defects‌
Includes outer fold, hairline, delamination, indentation, scratch, ear, edge and rolling. These defects are caused by tube surface defects, non-metallic inclusions, long heating time, improper handling or storage. These defects will affect the appearance and service life of seamless mechanical tubes. Strengthening tube quality control and optimizing heating process can reduce these defects.

7. Process problems
Mechanical steel pipes may have process problems such as improper heat treatment and poor welding during production, which may cause safety hazards such as cracking and leakage of steel pipes during use.

‌Preventive measures and maintenance methods‌:

‌1. Welding quality issues‌
Select qualified welding processes and equipment, strengthen welder training and skill improvement, conduct material inspection and pre-treatment before welding, and promptly discover and repair welding defects‌.

2. Corrosion issues‌
Select steel pipe materials with good corrosion resistance, carry out anti-corrosion treatment, strengthen daily maintenance, regularly inspect and maintain, and promptly remove dirt and scale on the surface of steel pipes‌.

3. Strength issues‌
Understand the load and strength parameters of mechanical steel pipes, make scientific selections, conduct acceptance and inspection before use, strengthen daily maintenance and maintenance, and regularly inspect and repair damaged steel pipes‌.

4. Insufficient dimensional accuracy‌
Dimensional deviations usually result from wear or unreasonable design of processing equipment. Manufacturers should regularly maintain and calibrate equipment to ensure processing accuracy. At the same time, the use of advanced CNC processing technology can effectively improve the dimensional stability of steel pipes.

5. Inner surface defects
For defects such as inner folds, inner scars, and warping, grinding or cutting should be carried out according to the specific situation; for inner straights and inner edges, grinding or cutting should be carried out according to standard requirements.

6. External surface defects
For defects such as outer folds, hairlines, and delamination, grinding or cutting should be carried out according to the specific situation; for defects such as indentations and scratches, repair or replacement should be carried out according to the severity.

Surface defects such as scratches, pits, and oxide scale are usually caused by improper processing, handling, or storage. In order to solve these problems, production should take effective packaging and protective measures to ensure that external forces are reduced during transportation and storage. In addition, regular surface treatment, such as polishing or pickling, can remove surface defects and improve the surface quality of steel pipes.

7. Understand the production process
Ask the supplier about the production process of the steel pipe and understand whether appropriate heat treatment and welding processes have been carried out to ensure the quality and safety of the steel pipe.

Methods to solve the quality problems of mechanical steel pipes:

1. Choose regular manufacturers: When purchasing mechanical steel pipes, you should choose regular manufacturers with good reputation and qualifications to reduce the risk of purchasing inferior steel pipes.

2. Strict acceptance: After receiving the mechanical steel pipes, strict acceptance work should be carried out, including appearance inspection, size measurement and material testing, etc., to ensure that the quality of the steel pipes meets the requirements.

3. Reasonable use and maintenance: When using mechanical steel pipes, they should be operated in accordance with the specifications to avoid excessive bending, impact and other behaviors that cause damage to the steel pipes. At the same time, regularly inspect and maintain the steel pipes to detect and deal with problems in time.

In short, it is crucial for users to understand the main types and identification methods of mechanical steel pipe quality problems. By choosing regular manufacturers, strict acceptance, and reasonable use and maintenance, safety hazards and economic losses caused by steel pipe quality problems can be effectively avoided.

Read more: Mechanical Tubing vs. Structural Tubing or ASTM A519 Seamless Mechanical Tube