The types of threaded steel bar connectors mainly include the following:
Sleeve extrusion connection joint: A joint formed by plastic deformation of the steel sleeve of the connector and tight engagement with the ribbed steel bar through extrusion force. There are mainly two forms: radial extrusion connection and axial extrusion connection. At present, radial extrusion connection technology has been widely used due to its excellent quality and construction convenience.
Taper thread connection joint: A joint formed by the engagement of the specially made tapered thread at the end of the steel bar and the tapered thread of the connector. The tapered thread connection technology has fast construction speed and low joint cost, but the cross-sectional area of the parent material will be weakened by machining the thread, resulting in reduced joint strength, which can generally only reach 85-95% of the actual tensile strength of the parent material.
Straight thread connection joint: Equal strength straight thread connection joint is the latest international trend of steel bar connection in the 1990s. This type of joint has stable and reliable quality, high connection strength, and is easy to construct and fast, gradually replacing the tapered thread connection technology.
Rough-iron straight thread connection: First, the end of the steel bar is roughened, and then cut to form a straight thread. This method ensures that the strength and precision of the joint are at a high level, but it requires two different equipment to complete it.
Direct rolling method to form threads: During the steel bar processing process, the end of the parent material is directly rolled to form threads. This method is easy to operate, but the thread quality may be slightly inferior to the method of roughing first and then cutting.
Rib extrusion rolling thread: Use special extrusion equipment to pre-press the transverse ribs and longitudinal ribs of the steel bar, and then roll the thread. This method improves the accuracy of the thread, but it still cannot completely eliminate the influence of the difference in steel bar diameter on the thread accuracy.
Rib stripping rolling thread: The transverse ribs and longitudinal ribs of the steel bar are stripped by the steel bar rib stripping rolling machine to ensure the uniform diameter of the raw materials before rolling, and then the thread is rolled. This method significantly improves the accuracy of the thread, ensures the stability of the joint quality, and speeds up the construction speed.
