Rolled Straight Thread Connecting Socket Technology Rolled Straight Thread Connecting Socket Technology

1. Equal-strength rolled straight thread connection technology for steel bars
Straight thread sleeve connection is a connection method in which the special straight thread at the end of the steel bar is occluded with the straight thread sleeve to form a whole. Reinforcement straight thread connecting sleeves with a diameter of Φ16～Φ40 can be made according to needs, and the connecting sleeves are made of No. 45 high-quality carbon structural steel or other steel materials that have been confirmed to meet the requirements after testing. The yield bearing capacity and tensile bearing capacity of the connecting sleeve are not less than 1.10 times the standard values of the yield bearing capacity and tensile bearing capacity of the connected steel bars. The performance of the joint complies with the provisions of JGJ-107-96A-level joint performance in the "General Technical Regulations for Mechanical Connection of Reinforced Steel Bars".
2 terms
①Straight thread thread head (referred to as thread head): the steel bar connection end rolled into a straight thread.
②Steel bar rolling straight thread joint: The connecting end of the steel bar is rolled into a straight thread thread head with a special machine tool, and the two steel bars with thread heads are connected into one piece of steel bar joint through the straight thread connection sleeve.
③Straight thread connection sleeve (referred to as connection sleeve): a steel connection sleeve with internal straight thread.
④ Bald teeth: The crest of the thread rolled by the steel bar is lower than the thread of the middle diameter.
⑤Effective screw thread: the part where the pitch diameter of the thread reaches the qualified geometric size.
2.2 Process flow
The technological process of steel bar rolling straight thread connection is: steel bar raw material → head cutting → mechanical processing (thread head processing) → wire sleeve plus protective sleeve → construction site connection.
① The processed steel bar should be straightened first and then unloaded. The end face of the cut is perpendicular to the axis of the steel bar, and there should be no horseshoe shape or deflection. When blanking, gas cutting is not allowed.
②Processing the thread shape of the thread, the thread must be consistent with the tooth shape and pitch of the connecting sleeve, and the cumulative length of the bald teeth in the effective thread is less than 1/2 of the circumference of a thread.
③ The wire heads that have been processed and passed the inspection should be protected. One end of the steel bar should be protected with a protective cap, and the other end should be screwed with a connecting sleeve, and they should be stacked neatly according to the specifications.
④ When the steel bars are connected, the specifications of the steel bars are consistent with the specifications of the connecting sleeve, and ensure that the thread head and the thread of the connecting sleeve are clean and undamaged.
2.3 Advantages of steel bar equal-strength rolling straight thread connection technology
① High joint strength: Equal-strength joints, 100% of the strength of the steel bar, can reach the A-level joint standard in the "General Technical Regulations for Mechanical Connection of Reinforced Bars" (JGJ-107-96).
② Fast connection speed: the sleeve is short, the number of threads is small, and it is easy to use. When connecting, put the sleeve on the steel bar and tighten it with a common wrench, which greatly reduces labor intensity and saves time.
③Wide range of applications: It is suitable for the connection of any position and direction of steel bars, and can also be used in occasions where bent steel bars and steel cages cannot be rotated.
④Strong applicability: The quality of the joint is reliable, and it is applicable to wind, rain, power failure, underwater and ultra-high environments during on-site construction.
⑤Material saving, energy saving, economical: In the connection of steel bars of the same level, it saves about 60% of the steel used for connection compared with traditional welding.
⑥Accommodating environmental protection requirements: There is no open flame during construction, and it is particularly safe and reliable under construction conditions such as flammable, explosive, and high places, and can be constructed around the clock.
3 Quality requirements and inspection
3.1 Quality requirements
① Thread head: The shape of the tooth is full, the width of the crest exceeds 0.6mm, and the cumulative length of the bald tooth part should not exceed the circumference of one thread. Outline dimensions including thread diameter and wire head length shall meet the drawing requirements.
②Sleeve: There are no cracks or other defects on the surface of the sleeve, and the external dimensions including the diameter of the inner thread of the sleeve and the length of the sleeve should meet the product design requirements.
③Connection: The connection is to ensure that the threaded head and the threaded button of the connecting sleeve are clean and undamaged. The sections of the two steel bars to be connected should be in the middle of the connecting sleeve, the deviation should not be greater than 1p (p is the pitch), and tightened with a work wrench to make the ends of the two steel bars tight.
3.2 Quality inspection
Processors visually inspect the processing quality of the wire heads one by one during processing. Inspection standards should comply with the provisions in Table 2. Every time 10 wire ends are processed, the corresponding ring gauge and wire end pallet should be tested once, and unqualified products should be eliminated. The thread ends that pass the self-inspection shall be randomly sampled and inspected by the quality inspectors on the thread ends processed by each specification. The thread ends produced in one working shift shall be taken as a random sampling of 10% of the inspection batch, and shall not be less than 10. If any If one thread head is unqualified, the sampling inspection should be doubled. If there are still unqualified thread ends in the re-inspection, all the silk ends of the batch should be inspected. The wire heads that have passed the inspection should be protected by plastic caps or connecting sleeves and protective plugs.
4 Normative Standards Cited
"JGJ-107-96 General Technical Regulations for Mechanical Connection of Steel Bars"; "Q/BSJJ06-2000 Technical Regulations for Steel Bar Rolling Straight Thread Joints".