In the construction of building projects, steel has an important role in the construction of the project, at the same time, according to the main structure of the building project, the construction technology related to steel also has certain differences, for this reason, through the change of the overall shape of the reinforcement and the change of thickness, etc., can ensure the smooth implementation of the construction, which requires the relevant welding technology of the reinforcement to guide the construction, the following paper will The following paper will discuss several common welding technology, so that it is applied in the specific construction of the construction, to truly achieve the quality of construction projects.
1 steel resistance spot welding technology
First of all, the main heat source used in resistance spot welding of steel welding technology is resistance heat, in the process of welding, through the transmission of current for welding of steel, welding under the influence of resistance heat will show certain changes, because this is a high temperature state, so the welding will gradually melt, then has a certain plasticity, under the influence of pressure, the formation of the corresponding welded joints.
In this welding technology, mainly contains three main forms, one is seam welding, two is butt welding, three is spot welding, in the use of spot welding process, mainly through the two electrodes between the energized heating, welding parts in this process will melt, also therefore the formation of molten core. At this time, the principle of pressure is used to crystallize the nucleus, which effectively ensures that the organization appears to have a dense character.
In the process of welding, the steel bar is effectively contacted in advance to ensure the flatness of the surface, so as to effectively ensure the welding quality of the steel bar, in the welding process there will be sparks in all directions, at this time to do a good job of safety protection, especially eye protection, with the movement of the steel bar, the contact point will be welded firmly. Finally, after the completion of welding, the processing of pressurization, the final processing is completed, the rebar is effectively welded.
There are many factors affecting the welding of steel bars, such as the parameters of welding, transformer level, etc. To ensure the quality of steel welding, these influencing factors should be fully considered, and on this basis, then choose the appropriate welding method, not only to ensure the effectiveness of the welding, but also in the economic point of view of the analysis, can also reach the ideal level. However, it is worth noting that the application of resistance spot welding technology presupposes a high-power welding machine.
2 Steel flash butt welding technology
The welding process using the construction process of flash butt welding of steel bars is mainly done at the ends of the bars, the top is processed for butt welding, and then the welding machine is heated, when the ends of the bars appear to melt, the two ends can be connected, and the bars are linked together in a high temperature state, because in the process of welding, there is a flash, so it is called flash butt welding of steel bars. The main form of this construction process also has three main forms, one is continuous flash welding, the second is flash – preheating – flash welding, three is preheating flash welding, different forms of butt welding technology applied in different situations, so from the actual situation, choose the appropriate welding process, the strengths and weaknesses to complete the welding of reinforcing steel, in the future construction, has a certain promotional significance.
3 rebar arc welding technology
Arc welding construction process in the use of the process needs to be equipped with a mask, because the use of a mask, so inevitably in the construction of personnel vision will be affected to a certain extent, if the working environment is restricted, then the overall quality of welding will also be seriously affected, most likely to cause substandard quality. Based on this situation, in the actual application, to ensure that the construction personnel in a serious state, and have a skilled operating techniques, so as to achieve effective construction. This construction technology is more stringent for beginners, so it should be paid enough attention to.
If you are a beginner, you should be careful to keep the current in the right range, keep the arc length short, and keep the welding speed slow and even. Before the start of welding, clean both sides of the joint about 20mm, clean the surface of rust, oil and water, keep the core of the welding rod can be exposed to the metal, so that it is easier to short-circuit the arc. There are two main methods of arc initiation: friction method and percussion method, of which the simpler one is friction method so it is suitable for beginners to use for arc initiation. Arc welding machine is divided into two kinds of DC and AC, which DC arc welding machine has the advantage of better welding quality and stable arc combustion, but the cost is higher, and because of the complex structure so difficult to maintain, operating noise, for important workpiece welding is more suitable.
4 Electroslag pressure welding technology for steel bars
Electroslag pressure welding is a kind of melt pressure welding, for those horizontal bars or those inclined bars with a slope greater than 4:1 is not applicable, but also not suitable for welding those poor weldability of steel bars, if the welder level is low, poor power supply conditions or voltage instability and those need strict fire prevention occasions are not suitable for the use of electroslag pressure welding technology. The welding process starts with the upper and lower bars in contact, then the welding power is turned on and the arc is ignited by immediately lifting the bar within 2-4mm, then slowly and continuously lifting it up to keep the arc in a stable burning state at 5-7mm. The rebar is continuously melted at temperature and then slowly sent downward for the next step in the electric frying over slag process.
5 Pneumatic butt welding technology for reinforcing steel
As a long-term application of rebar welding technology, voltage butt welding in the long-term application of the process of practice has been constantly modified, after the continuous efforts of technical personnel and welders pneumatic butt welding construction technology continues to develop and improve, has become more mature, so the most commonly used in the construction of construction projects is the rebar pneumatic butt welding technology. Pneumatic butt welding technology in accordance with the characteristics of different rebar form changes can be divided into two, solid state pneumatic welding method and molten state pneumatic welding method, which is a relatively simple method of operation while the construction process is also more simple is the molten state pneumatic welding method, for the welding quality and welding speed of rebar have been greatly improved. From the pneumatic welding equipment is also in the long-term use of the process of continuous refinement and improvement, in the future construction of steel pneumatic butt welding technology will have a very broad development prospects and will play a great role.
6 pre-buried steel submerged arc pressure welding technology
Pre-embedded steel submerged arc pressure welding technology may appear in some cases, such as its rebar and steel plates do not get a full degree of welding reunion, so the extrusion of the weld metal and rebar is not reunited with the state of separation. The reason for this is that the current is too small and short during the welding process, and the base material is not sufficiently heated, and there is not enough molten pool metal, so there is a fast cooling rate, and the weld is not complete when the top pressure is applied.
Or the welding process is too high in the arc lift as well as the down feeding process is not stable enough, interrupting the melting process. Want to prevent problems in the submerged arc pressure welding technology for pre-built steel, first of all, the top pressure should be increased, followed by a combination of specific rebar size to maintain the arc lift height, arc voltage welding current and welding time appropriate, from all aspects of the welding process to maintain more stable.
Conclusion
Rebar connection is inseparable from the important process of rebar welding, which has an important role in building construction. The above-mentioned are commonly used in the construction of building construction rebar welding technology, usually analyze the focus of various technologies, the construction process technicians should be based on the actual situation to choose the right rebar welding technology to ensure the quality of rebar welding in building construction.