The space grid structure is now put into use in many industries, and the total number of bolt balls used in the grid is also increasing. The editor of Jiangsu Huahai Steel Structure will briefly introduce the installation and reinforcement of bolt balls.

One, the solution to the non-round weld

In some engineering projects, the welding seam of the steel pipe and the cone or the connecting plate is often not round, especially for some large pipe diameters, thick wall pipes and rods, it takes several times to weld to get a wide and thick weld. Sew. Carelessness of the electric welder can easily cause the welding seam to be not round, such as leaning on the welding seam with a scale, the welding seam dents at the welding wire joints are 1-2 mm or even large, or appear very large. It is feasible to carry out under the effect of its own weight. For the net frame with the roof static load fully covered, appropriate support points should be provided, or welded in sections at intervals to prevent high temperature at the full cross-section of the rod. Circumstances, because the stainless steel plate will lose part of its bearing capacity at high temperatures.

2. Secondary electric welding in the thermally hazardous area of welded parts

When installing rods, it is often necessary to re-use the taper at the welding seam. At this time, there is a problem of secondary electric welding in the heat-hazardous area of the original weld. Therefore, everyone has to mill the electric welded taper again. Weld the steel pipe again and make a total of 15 tensile tests. After the tensile test, the damaged locations are all in the butt weld of the steel pipe, that is, in the area without the thermal hazard of the cone. The inverse calculation of the in-situ stress of the steel pipe achieves the compressive strength of the steel pipe, which indicates that it is reliable to carry out secondary electric welding in high carbon steel such as 0235 or 20 steel in the heat-hazard area of electric welding.

Third, the production and processing of cones and the solution of quality problems with steel pipe assembly and welding products

The limit error of the coaxiality between the midpoint of the cone end hole and the midpoint line of the steel pipe often exceeds 0.2 mm during the installation of the grid rods, which also exceeds the released limit error value of 1.0 mm, and the conical head inclined wall is not connected to the base plate. Round the corners. The damage of this kind of situation is that the rod is in the bending process or bending condition, and the other is the stress of the unrounded corners and the reduction of the bearing capacity.

Fourth, the solution to the impact of the rod at the ball connection point

In the installation of the grid, the bearing steel ball is very small, which is easy to cause the rods to collide and encounter obstacles during the installation. On the contrary, in the production and processing of large and medium-sized grids and the construction drawings of unique design grids, bolt balls with a diameter of more than 300 often appear. That is to say, the bearing steel ball is too large, due to the harm of many factors such as the sales market, production and processing, and on-site installation, and then the installation work is blocked. The processing of bearing steel balls is very small, which is easy to cause collision of rods, and can be carried out in the following way. When the standard is convenient, it can change the big ball and reform the relative rod, otherwise, part of the cone and rod of one of the collision rods will be burned off, and then imitated a thick steel plate with a thickness of 2-4mm than the wall thickness. . The cut edge of the cone and the rod and the welded thick steel plate should be welded 2 to hold the sand wheel 3 by hand. After the welding, hold the sand wheel by hand to tie, clean the rust and repair the anti-rust treatment surface Paint two layers.