Application Status and Development of Welding Gas
In the field of metal processing, welding is a very important process, which has an important impact on the operation efficiency, product quality, occupational health and environmental protection. With the increasing popularity of industrial production automation and the improvement of welders' health concepts and awareness, welding automation has also evolved, which can be clearly felt from the Beijing Essen Welding Exhibition over the years. In the past, only international companies owned automated welding systems and robotic welding systems. Most of the domestic welding machine manufacturers have also introduced such systems.
The most suitable welding method for gas welding can be to fully utilize the welding efficiency, adaptability to different product structures and full position capability of these systems. The traditional electrode arc welding can not achieve continuous wire feeding, and can only be limited to manual welding; high-efficiency submerged arc welding can not achieve all-position welding, and both methods will produce a large amount of welding slag, which makes continuous welding difficult. The working environment is also very friendly.
Nowadays, due to the increasing number of factory approvals for robot welding, the number of installed machines is also increasing. Therefore, the variety and application requirements of welding gas are also increasing. The same materials, different products, different quality requirements may be Choose a different welding shielding gas to achieve. At present, most of the factories in China use carbon dioxide. The gas is cheap, and the welder's skill requirements are low. However, they are also trapped in the problem of poor weld formation, large residual height, and spattering. Europe and the United States use argon and carbon dioxide. Gas, better solved the above problems.
This case is a comparative test of Air Liquide's ARCAL5 (Ar+CO 2 ) and CO 2 . Under the same welding test conditions, the appearance quality of the test weld is shown in Fig. 1 and Fig. 2. The basic elements of the test are shown in Table 1, and the welding cost and efficiency analysis are shown in Table 2.
Most customers only pay attention to the price of gas, because the price is very intuitive, but it is not correct. The welding cost is not only gas (see Table 2), but also welding wire cost, welding labor cost, splash cleaning labor cost and electricity cost. The total cost of welding 1.8m long fillet with mixed gas is 0.65 yuan lower than CO 2 . (5.40-4.75), a factory with 20 welding machines, 250 days a year, can save welding costs of 306,000 yuan throughout the year; in addition, welding efficiency increased by 28%, because the welding time of a single workpiece is shorter than CO 2 .
This case shows that the correct choice of welding shielding gas is very obvious for improving welding quality and efficiency, reducing welding costs, and there is no additional equipment procurement expenses.
International standard for welding protective gas
Air Liquide's ARCALTM brand of welding shielding gas is manufactured in strict accordance with ISO 14175 (welding consumables â€“ gas and mixed gases for fusion welding and related methods) to achieve a fully computer-controlled automated process that avoids human error and ensures The accuracy requirements of the mixing ratio; the impurities affecting the welding quality, such as moisture, oxygen content and nitrogen content, are strictly controlled by gas source procurement, plant analysis, filling procedures, vacuuming and special bottle valves. Technical requirements for the application. Since 2011, the American Welding Association has also used this standard, the standard number is AWS 5.32.
Gas development direction
For a variety of materials and welding methods, combined with the characteristics of different gases in arc characteristics, thermal conductivity, wettability and metallurgy, Air Liquide's welding research and development center in France has developed a series of welding shielding gas.
(1) ARCAL121 (Ar+He+CO 2 ) is used for gas shielded welding of stainless steel and high-strength steel, the optimal ternary gas mixing ratio, higher welding speed (low heat input), good wettability, Very low weld carburization and oxygen and hydrogen content can improve the corrosion resistance of stainless steel and the low temperature impact toughness of high strength steel. The test confirmed that the shock absorption energy of 690MPa high-strength steel can reach 140J, which is obvious compared with the traditional 80% Ar+20% CO 2 gas.
(2) ARCAL33/37 (Ar+He) is used for gas shielded welding of aluminum alloy and copper, which reduces the preheating temperature or cancels the preheating, greatly simplifying the welding process and operability. And compared with pure argon, the welding speed is increased by more than 30%, and the strength of the welded joint is effectively controlled to be weakened; and the number of hydrogen holes is greatly reduced.
(3) ARCAL11 (Ar+He+H2) has unique advantages in the welding of nickel-based alloys, which can obtain satisfactory penetration and weld profile, and can make the surface of the weld be slightly oxidized, and the burning of alloying elements is very good. Low, the performance is guaranteed to be reliable. With the development of new welding processes and new materials, the future development trend of welding gas is mainly reflected in: easy to use, high efficiency, high quality, safe and healthy.
Safety concept and pursuit
Liquefied air is a company that pays great attention to safety. Safety indicators have been prioritized when designing welding products. This includes two aspects: one is the safety requirements for production and transportation in internal plants; the other is when used by external clients. , to protect and meet customer safety requirements.
Specifically embodied in the following points:
First, provide a product safety data sheet in the contract.
Second, the product identification is clear, including: product name, gas type, physical and chemical properties, pressure rating, filling manufacturer information and shipping label.
Third, there have been many changes in gas products and their industries over the past 100 years, and the cylinder itself has not changed. Air Liquide has been looking for a better gas packaging product. The results of surveys from many companies around the world have become a key word for safety, simplicity and money saving. After 5 years of research and testing, the ALTOP product was invented. The cylinder valve shown in Figure 3 integrates an argon gas meter. The welder only needs to use the quick-release and air outlet connections to isolate the direct contact with the high-pressure gas, greatly reducing Safety risks; at the same time, the ALTOP bottle cap protects the bottle valve in an all-round way and improves the safety of the product. The design won the 2013 "Junge Award".
In the face of increasingly fierce commercial and technological competitive environments, the application status of welding shielding gas is gradually increasing. As the majority of welding workers become more aware of it, the â€œsmall cost and big effectâ€ of welding gas will show more charm.
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