To Improve Welding Quality, You Must Know These Knowledge

In today's industrial manufacturing and many fields that require connection processes, welding is undoubtedly a crucial technology. The quality of welding directly affects the performance, safety, and service life of products in industries such as automobile manufacturing, electronic equipment production, and construction engineering. As a professional welding machine manufacturer, PDKJ will share with you some key knowledge to improve welding quality today.

01. Preparation before welding

1. Material cleaning: This is often overlooked but extremely critical. If there are impurities such as oil stains, rust, and oxide scales on the surface of the material to be welded, it will seriously affect the quality of the welding. For example, when welding metal plates, surface oil stains can create pores during the welding process, reducing the strength of the weld seam. So before welding, it is necessary to use a suitable cleaning agent, such as acetone or other organic solvents, to wipe and clean the metal surface, or remove rust and oxide scale through mechanical polishing to ensure that the welding surface is clean and tidy. Only in this way can the weld seam and the base material achieve good fusion during subsequent welding.

2. Material matching: Correctly selecting welding materials that match the base material is also the foundation for ensuring welding quality. Different base materials have different chemical compositions and mechanical properties, which require the selection of suitable welding materials such as welding wires and rods. For example, when welding stainless steel, specialized stainless steel welding wire should be selected, whose chemical composition can better integrate with the stainless steel base material, avoiding quality problems such as poor corrosion resistance and cracking at the weld joint. At the same time, the specifications of welding materials should also meet the requirements of the welding process. Welding wires that are too thin may not provide sufficient filling, while those that are too thick may result in uneven deposition.

3. Equipment debugging and inspection: For welding equipment such as spot welding machines and laser welding machines, comprehensive debugging and inspection must be carried out before welding. Suitable welding parameters should be set according to the thickness and material of the welding material, such as the welding current and welding time of the spot welding machine, the laser power and pulse frequency of the laser welding machine, etc. And it is necessary to check whether the electrodes of the equipment are worn and whether the key components such as the laser generator are working properly. If the electrode is severely worn, stable and reliable welding points may not be formed during spot welding, resulting in virtual welding or insufficient strength of the welding points; The failure of key components in laser welding machines can cause unstable laser energy, affecting the formation and quality of the weld seam.

02. Key points to control during the welding process

1. Precise control of welding parameters: During the welding process, even small changes in parameters may have a significant impact on the welding quality. Taking laser welding as an example, if the laser power is too high, it may cause the weld seam to burn through, which not only affects the appearance but also damages the mechanical properties of the weld seam; However, if the laser power is too low, there may be incomplete fusion of the weld seam, which cannot achieve the expected connection strength. Similarly, for spot welding machines, excessive welding current can easily cause splashing, waste welding materials, and may also form defects around the welding points; If the current is too low, the solder joint will not be firm. So operators need to continuously accumulate experience based on actual welding conditions, accurately adjust and control welding parameters, and ensure stable welding processes.

2. Reasonable control of welding speed: Welding speed is also a key factor. If the speed is too fast, the weld pool may not have enough time to fully cool and solidify, which can easily lead to defects such as incomplete fusion and porosity; Slow speed and excessive heat accumulation may not only burn through the material, but also expand the heat affected zone of the weld, resulting in changes in the properties of the base material, such as reduced toughness of the metal material. For example, when welding some thin-walled pipe fittings, it is necessary to control the welding speed appropriately to ensure that a good welding connection can be achieved without adversely affecting the structure and performance of the pipe fittings themselves.

3. Consideration of welding environment: The welding environment cannot be ignored in terms of quality. Welding in a humid environment can easily allow moisture to enter the weld seam, forming hydrogen pores and reducing the quality of the weld seam; In environments with strong winds, welding protective gases (such as argon) can be blown away, causing oxidation of the weld seam and affecting its appearance and corrosion resistance. Therefore, welding operations should be carried out in a dry, sheltered, and relatively clean environment as much as possible. If welding in harsh environments cannot be avoided, corresponding protective measures need to be taken, such as building windbreaks and using dehumidification equipment.

03. Quality inspection and treatment after welding

1. Appearance inspection: After welding is completed, the first step is to conduct an appearance inspection. Observe with the naked eye whether the shape and size of the weld meet the requirements, and whether there are defects such as cracks, pores, undercutting, and lack of fusion on the surface. For example, undercutting can reduce the effective cross-sectional area of the weld seam and lower its load-bearing capacity; The presence of obvious cracks on the surface is a serious quality hazard, which may lead to sudden fracture of the welded structure during use. For welds that do not meet the quality standards in appearance, timely repair treatment should be carried out.

2. Non destructive testing: In order to comprehensively evaluate welding quality, non-destructive testing techniques such as ultrasonic testing, radiographic testing, magnetic particle testing, etc. are also needed. Ultrasonic testing can detect defects such as porosity and slag inclusion inside the weld seam; Radiographic testing can clearly present the internal structure of the weld seam and detect small cracks and other issues; Magnetic particle testing is suitable for detecting defects such as cracks on the surface and near surface of ferromagnetic material welds. Through these non-destructive testing methods, quality problems hidden inside the weld seam can be detected in a timely manner, so as to take targeted measures for repair or scrap unqualified welded parts, and avoid products with quality hazards from entering the market.

3. Heat treatment: In some specific cases, heat treatment after welding can help improve the performance of welded joints, eliminate welding residual stresses, and enhance the strength and toughness of welds. For example, for some medium and high carbon steel welded structures, tempering treatment after welding can make the weld structure more uniform, reduce hardness, improve toughness, and prevent cracking during subsequent use.

IN GENERAL

The improvement of welding quality is a systematic project, from careful preparation before welding, rigorous control during the welding process, to strict inspection and necessary treatment after welding, every link is crucial. As a professional manufacturer of spot welding machines and laser welding machines, we are always committed to providing customers with high-quality welding equipment, and hope to use this popular science knowledge to help more welding practitioners improve welding quality, create higher quality and more reliable welding products, and jointly promote the high-quality development of various industries.  

I hope everyone remembers these key points in welding practice and takes welding quality to the next level!