I. Overview In the research process of surfacing welding materials, we found that simply meeting the user's requirements for the performance of the surfacing layer is far from enough, and the environmental problems in the use of materials are becoming more and more important.
In the initial research and production stage, due to financial and time reasons, we will focus more on the design of the use of welding materials, pay less attention to the welding process performance of the material, that: as long as the wear resistance of the material Corrosion resistance can meet customer needs, even if the welding process is poor, but the material use effect is good, the cost performance is ideal, there will be a market, as for the welding process, the smoke is not big, the splash is serious or not, the weld slag is not good, etc. A series of questions have not received enough attention. Then, for a long time, we can see many welding materials in China. The surface of the workpiece after surfacing is densely packed, the inclusion is serious, the surface of the weld is flat, the splash particles are much adhered, and the appearance quality is very poor. To a certain extent, it affects the effect of its use, but because there are few varieties of domestic hardfacing materials at the time, users do not have much choice.
As the market competition continues to intensify, we have gradually mentioned environmental protection-related issues on the agenda in the in-depth study of materials. As the market matures and foreign brands are advancing in the domestic market, they are only satisfied with the user's use requirements, regardless of the operability of the welding materials. Even if the performance is good, it may end up due to environmental reasons and not subject to the on-site welder. Welcome and eventually lose the existing market share.
2. Welding environmental protection problems in welding materials for surfacing
1. Smoke and anti-porosity problems Due to the high content of alloys, in general, the smoke is large, especially in the environment where the on-site station space is small and the air circulation is not smooth, the welding will not take too long, and the smoke will linger. .
(1) Anti-moisture problem of welding rods When we promoted wear-resistant and anti-cavitation welding rods in hydropower plants, we found that the surface repairing turbine blades are mostly carried out in the pits. Due to the underground environment, the pit environment is very humid due to a major overhaul period. For more than half a month, it is necessary to weld 3~4t welding rods. The workload is quite large. It is too late to use the existing baking. This requires the
Welding Rod to have very good moisture resistance. Even if it is used under damp conditions, the surfacing layer will not be Porosity occurs (if there is a pore in the weld overlay layer, it must be cleaned up in time, otherwise it will be a source of cavitation).
In addition, since the welding space is very small and the air circulation is not good, the amount of dust generated by the welding rod should be as small as possible. Otherwise, the air quality of the worker during continuous welding is rather poor, which is very harmful to the worker. Therefore, for the special working conditions, we have continuously improved the performance of the welding rod, so that the anti-moisture performance of the welding rod has met the requirements of the site. Even when the electrode accidentally falls into the water, it is no problem to fish it up and reuse it.
(2) Smoke problem For the problem of smoke in welding, on the one hand, we actively communicate with the user, it is recommended to strengthen the ventilation at the welding station; on the other hand, we also reduce the welding dust from the alloy ratio of the electrode itself and the adjustment of the slag system. The amount has achieved certain effects, but it is still to be further studied.
However, as the welding industry continues to pay more attention to environmental issues, we believe that more people will invest in this area of research, and domestic brands will eventually do well.
2. Splash and slag removal problems In the on-site repair of large workpieces, it was found that the slag removal problem seriously affected the welding efficiency. Generally, before welding large parts, preheating will be carried out according to different conditions, and continuous welding will be carried out. If the welding rod or wire slag is thick, the slag will be very difficult to clear, and it will easily affect the formation of welds, causing inclusions and detecting the weld surface. If it is not closed, or the flatness of the weld overlay is not good, it is necessary to weld a certain thickness to solve the problem and increase the repair cost. In response to this problem, we use the slag-free or less slag-based system as much as possible. The welding wire is made of metal powder, so that there is basically no problem of slag cleaning during the surfacing process, which reduces the labor intensity.
The biggest disadvantage of the slag-free type is that it has a large splash during welding. Especially when the new product is pre-protected and surfacing, if there is a large splash during the welding process, there will be many splash points on the surface of the product, which is not allowed by the new product. After the cleaning of the splash work is very annoying, after the workpiece is welded, the tailing work should be completed in half a day, but sometimes due to more splash points, the post-cleaning work may need to increase the time of day; at the same time, the amount of splash is large, which also affects the effective material. Utilization rate. In response to this problem, we timely adjusted the product, appropriately adding the elements of the refined droplets, so that the large particle splash is significantly reduced, and the small particle splash is easier to clean and control from the total amount of splash.
Third, strengthen the research and development of environmental protection issues, it will help the welding materials to embark on a healthy development of green environmental protection. With the continuous development of welding materials research, more and more peers realize the importance of environmental protection to the development of the industry. . At the same time, building a people-oriented harmonious society requires us to focus more on reducing the pollution of welding materials to the environment.
With a large number of foreign brands flooding into the country, we have also seen a gap compared to it. In the past, we paid little attention to environmental issues in product design, product manufacturing, product packaging and product transportation. At this stage, if we are required to do a perfect job in all aspects, it seems that it is not realistic. However, as long as we can start from now, fundamentally attach importance to this issue, and strengthen environmental awareness, we will bring this concept to different links, gradually improve our production quality system, and finally realize the "State Council" The green remanufacturing project will enable welding materials to embark on a healthy and green road. (20060712)
August 12, 2022
