Cold-pressing technology for making equistrength archor arm and its end

Abstract

A cold-pressed equistrength archor rod for supporting gallery has rod body and end part, and is made through cold (rolling) pressing the rolled rod body with axial spiral ribs to remove the ribs at head part and become a cylinder, and screwing the cylindrical head part. Its advantages are high strength, strong anchor power, and no stress concentration.

Description

Technical field: [0001] The invention relates to mining support technology for mine resources, and relates to a cold-press head and other strong bolt used for underground mining roadway bolt support and a processing method thereof. Background technique: [0002] The existing anchor rods generally have one-way left-handed ribs and no longitudinal ribs. After many improvements, good support effects have been achieved. However, in practice, it is found that the existing anchor rods still have many shortcomings: when fully anchored, The effect of adequate mixing of the anchoring agent is not good, the grip force of the rod body is slightly poor, the pitch, height, angle, and weight of the rib are too large, the rod body is not round, and the resistance to propulsion and rotation of the anchor rod is easy to be large, and the force is easily transmitted to the rib. Frequently passing the anchor rod through the anchoring agent reduces the stirring effect and causes poor anchoring ...

AI Technical Summary

Problems solved by technology

[0002] The existing anchor rods generally have one-way left-handed ribs and no longitudinal ribs. After many improvements, good support effects have been achieved. However, in practice, it is found that the existing anchor rods still have many shortcomings: when fully anchored, The effect of adequate mixing of the anchoring agent is not good, the grip force of the rod body is slightly poor, the pitch, height, angle, and weight of the rib are too large, the rod body is not round, and the resistance to propulsion and rotation of the anchor rod is easy to be large, and the force is easily transmitted to the rib. Frequently make the anchor rod pass through the anchoring agent to reduce the stirring effect and cause poor anchoring force

This processing method reduces the effective cross-sectional area of ​​the threaded section, and then loses 15-25% of the tensile strength of the base material of the anchor rod, and causes the anchor rod to form stress concentration during use and break first.

2. The disadvantage of thermal processing is that it produces iron oxide scale, thermal expansion and cold contraction cause extension, cylindrical body is thinner than the base metal rod body, and the size error is too large, so it is difficult to achieve the strength of the anchor rod body.

Images