Here are some specific methods to prevent material defects in SSAW Steel Pipes:

Raw material procurement and inspection process

Selected suppliers: Priority should be given to large and well-known steel enterprises as raw material suppliers, which usually have strict production management and quality control systems and can provide stable and reliable steel quality.

Detailed contract agreement: Clearly stipulate the quality standards, inspection methods, acceptance rules, and quality responsibilities of raw materials in the procurement contract to ensure that the steel provided by the supplier meets the requirements, and have clear responsibility definitions for possible quality problems.

Strict appearance inspection: When raw materials enter the factory, the surface quality of the steel is strictly inspected to see if there are obvious defects such as cracks, folds, scars, inclusions, etc. Defective steel should be promptly returned for processing.

Chemical composition retest: According to relevant standards and specifications, each batch of raw materials is sampled and retested for chemical composition to ensure that the content of major elements such as carbon, silicon, manganese, sulfur, phosphorus, as well as alloy elements such as chromium, nickel, molybdenum, etc. meet the specified range, and to prevent material defects caused by unqualified chemical composition.

Production process control link

Steel making process control

Accurate batching: Based on the performance requirements of SSAW steel pipes, accurately calculate the ratio of various raw materials to ensure the uniform and stable chemical composition of the molten steel.

Deoxygenation and refining: Reasonable deoxidation processes and refining methods, such as aluminum deoxidation and LF furnace refining, are used to effectively remove harmful gases and inclusions such as oxygen, hydrogen, and nitrogen from molten steel, and improve the purity of molten steel.

Slag control: Strictly control the composition and properties of steelmaking slag, so that it has good fluidity and the ability to adsorb inclusions, promoting the upward floating and removal of inclusions.

Optimization of Rolling Process

Heating system: Develop reasonable heating temperature, heating speed, and insulation time to avoid defects such as overheating and overburning of steel caused by improper heating, which may affect material properties. Generally speaking, the heating temperature should be precisely adjusted according to the chemical composition and specifications of the steel.

Rolling parameter adjustment: Based on the size and performance requirements of the steel pipe, reasonable selection of rolling passes, rolling speed, and reduction amount parameters should be made to ensure that the steel pipe can obtain good microstructure and performance during the rolling process. For example, increasing the rolling passes and reduction appropriately can refine the grain size and improve the strength and toughness of steel pipes.

Cooling control: Adopt appropriate cooling methods and rates to cool the rolled steel pipes, such as controlling the air cooling speed, water cooling time, etc., in order to obtain ideal metallographic structure and mechanical properties. For high-strength SSAW steel pipes, a combination of rapid cooling and tempering treatment is usually used to improve the overall performance of the steel pipe.

Heat treatment process specification

Normalization treatment: Normalizing the rolled steel pipe can refine the grain size, eliminate structural stress, and improve the comprehensive mechanical properties of the steel pipe. The normalizing temperature should generally be determined based on the material and specifications of the steel pipe. The heating speed should not be too fast, and the insulation time should be sufficient to ensure uniform and consistent temperature inside and outside the steel pipe.

Tempering treatment: For some high-strength or high hardness SSAW steel pipes, tempering treatment is required after normalizing to eliminate the internal stress generated during the normalizing process, improve the toughness and fatigue resistance of the steel pipe. The tempering temperature and insulation time should be strictly controlled according to the specific requirements of the steel pipe.

Quality inspection and monitoring process

Online testing: Install advanced testing equipment on the production line, such as eddy current testing, laser calipers, etc., to perform real-time online testing on the dimensional accuracy, surface quality, wall thickness uniformity, etc. of steel pipes, and promptly detect and eliminate non-conforming products.

Full coverage of non-destructive testing: Various non-destructive testing methods such as ultrasonic testing, magnetic particle testing, and radiographic testing are used to comprehensively test the welds and raw materials of SSAW steel pipes, and the testing ratio should meet the requirements of relevant standards and specifications. For important parts or high stress areas, the combination of testing frequency and methods should be appropriately increased to ensure reliable internal quality of the steel pipe.

Physical and chemical performance sampling: Regularly conduct physical and chemical performance sampling on SSAW steel pipes produced, including tensile testing, impact testing, hardness testing, metallographic analysis, etc., to verify whether the mechanical properties and metallographic structure of the steel pipes meet the standard requirements. The sampling frequency should be determined based on the production batch and quality stability. Generally, each batch or a certain quantity of steel pipes should undergo at least one comprehensive physical and chemical performance test.

Process monitoring and data analysis: Utilizing advanced production process monitoring systems, real-time monitoring and recording of process parameters such as temperature, pressure, speed, etc. in key production processes such as steelmaking, rolling, and heat treatment. By analyzing a large amount of production data, abnormal changes in process parameters can be detected in a timely manner, potential material defects can be predicted, and corresponding adjustment measures can be taken.

Personnel and equipment management process

Personnel training and assessment: Regularly organize production personnel to participate in professional technical training and quality awareness education activities, so that they are familiar with the production process, quality standards, and operating procedures of SSAW steel pipes. At the same time, establish a strict personnel assessment system to ensure that operators have the corresponding skill level and quality control ability, and are certified to work.

Equipment maintenance and updates: Strengthen the daily maintenance and upkeep of production equipment, regularly inspect and calibrate the equipment to ensure its normal operation and accuracy maintenance. For aging and outdated equipment, timely updates and renovations should be carried out, using advanced production equipment and process technology to improve the production quality and stability of steel pipes.