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The process of machining the rods in the space frame structure

Rod processing is an important part of the construction process of a space frame project which is easy to causes the accumulation of errors. One of the composition of the rod of the steel pipe size, the thickness of the sealing plate or cone head, and the thickness of the weld seam to determine the final length of the rod, and by the length of the rod design value of the constraints of the steel pipe size, the thickness of the sealing plate or cone head and determines the thickness of the weld seam, weld seam is too large or too small are directly affecting the strength of the connection of the rod. Therefore, the specific construction process should be for different weldments and their weld thickness requirements to control the steel pipe size, which requires the same specifications of the rod first to make a “sample rod”, to achieve the purpose of correcting the size of the material. The other control point of the rod processing is the verticality of the end face, and the verticality of the end face determines the size of the contact surface between the rod and the bolt ball. For the space frame in the pressure-bearing rods, not vertical rods, in the role of the actual bearing capacity, the rods are often eccentrically pressurized, a single member makes the rods not give full play to their performance and deformation, the multi-member case will reduce the safety performance of the space frame. This requires the welding of both ends of the rod before the temporary “rod” to strengthen the parallel check, which is also essential to the “rod platform” check. A good “rod platform” should make the composition of the rod components free and independent of each other, so that the “rod” can achieve better results. Each member should be checked for bending. Therefore, “rod” work is very critical work. Should not be blindly pursuing speed, so as not to cause great potential danger to the subsequent work or lead to unnecessary rework.

Various forms of quality defects may appear when the rod steel pipe is welded with the sealing plate or cone head, such as weld clusters, weld holes, biting edges, weld opacity, uneven weld, etc. The reasons should be analyzed for different defects and then rectified one by one according to the reasons for the formation of the defects. After practice, the main reasons for the formation of the above quality defects are summarized in Table 1:  


Defect Forms

Reasons for formation


weld tumor

Weld closures are prone to


weld hole

Incomplete cleaning of the first weld slag



Excessive current value



The current value is too small


Uneven welds

Uneven pre-welded surfaces

In addition, the quality of the electrode, storage time, and baking conditions are also important aspects affecting the quality of the weld. After welding, the weld should be cooled down naturally at room temperature to ensure the stability of the weld material.

Rust removal on the rod to ensure that the design level, for the rust stains too heavy pipe and storage time, is too long to carry out the second shot blasting, rust removal at the same time for the appearance of the inspection, whether there are defects in the rod itself. Rust removal racks should not be too dense, to effectively ensure a full range of spray rust removal.

Painting is the final process for the formation of the space frame rods. Paint is generally in the appearance of the phenomenon is not allowed to fall, spraying should be uniform, and can not have the bottom of the permeability. It is necessary to ensure that the second coat of paint can be applied only after the first coat of paint has dried.

In addition to the space frame rod processing process at the same time to the bolt, the sleeve for the necessary appearance checks, bolts to Rockwell hardness test, rod welds according to specifications and batches to do flaw detection test, welding rod into the factory before the reliability of the test, the combination of finished rods to do the tensile strength test and so on.